JP2005103618A - Method for manufacturing pulley - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an advantageous method for manufacturing a lightweight multi-grooved pulley with high quality, in which flange portions excellent in strength and free from forming defect are provided on both ends of a rim portion. <P>SOLUTION: A preform 22 comprises a tapered cylindrical section 28 of which the upper open side is larger in diameter than the lower side, and a disc-like bottom section 24 which corresponds to the base of the intended pulley. A tapered roller is pressed against the outer circumferential face of the upper flank part of the tapered cylindrical section 28 of the preform 22 whereby, at the middle part of the tapered cylindrical section 28 in the vertical direction a flection 74 is formed so as to form the part higher than the middle part of the tapered cylindrical section 28 into a reversely tapered cylindrical shape. Then a forming roller is pressed against the outer circumferential face of the flection 74 whereby a thickened cylindrical part is formed and projections which protrude outward in the diametrical direction are formed respectively on both ends of the thickened cylindrical part. The thickened cylindrical part and two projections form the rim portion and two flange portions so that the objective pulley is manufactured. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pulley manufacturing method, and in particular, a shaft of a cylindrical rim portion around which a belt is wound by rolling a bottomed tapered cylindrical preform obtained from a predetermined metal plate material. The present invention relates to a method of advantageously manufacturing a pulley in which flange portions are integrally formed at both ends in the direction.

  In general, a pulley as a belt wheel constituting a transmission mechanism using a belt includes a disk-like base portion attached to a rotation shaft (drive shaft) of a predetermined drive source such as a motor or an engine, a flat belt, a V belt, V And a cylindrical rim portion around which a ribbed belt or the like is wound. And the flange part extended toward radial direction outward is provided in the both ends site | part of the axial direction of this rim | limb part, respectively, The width direction of the belt wound around a rim | limb part by these two flange parts is provided. Misalignment can be prevented.

  In addition, various methods for manufacturing such pulleys have been proposed, and one of them is, for example, a large disc-shaped bottom and upper opening corresponding to the base of the target pulley. A bottomed tapered cylindrical preform having a tapered cylindrical portion having a diameter is used, and the first mold and the first mold are positioned coaxially and rotatably about the central axis at the bottom of the preform. A predetermined forming roller is formed on the outer peripheral surface of the tapered cylindrical portion of the preform in a state of being coaxially sandwiched between the two molds and integrally rotated around the first and second molds and the central axis thereof. , While bending the taper cylinder part into a cylindrical shape, compressing in the length direction to form a thickened cylindrical part, while at both ends of this thickened cylindrical part, One projecting part projecting radially outward A method of forming a desired pulley by forming a rim portion and two flange portions by the cylindrical portion and the two projecting portions by performing rolling processing to form each one, Is known (see, for example, Patent Document 1 and Patent Document 2). In this method, the shape corresponding to the belt wound around the rim portion is usually formed after the rim portion is formed by grooving the rim portion by rolling using a groove forming roller. A plurality of the grooves are formed.

  In such a pulley manufacturing method, the rim portion and the flange portion are formed into a thick cylindrical portion formed by thickening from the tapered cylindrical portion of the preform by rolling. For example, by performing a predetermined rolling process on a bottomed cylindrical preform obtained by drawing a circular metal plate material, a rim portion is obtained, and a base side end of the rim portion is obtained. A well-known pulley manufacturing method is adopted in which the part is folded in half and a flange is projected from the connecting part (boundary part) between the base of the pulley and the rim, where a large load is applied based on the belt tension. The strength of the flange portion can be effectively increased as compared with the case where the taper tube portion is made, and since it is not necessary to bend the taper tube portion of the preform, the length of the taper tube portion becomes longer than necessary. It can be prevented, whereby the preform is to be made possible to advantageously reduce the weight of the entire pulley turn.

  By the way, in the pulley, as the number of grooves formed in the rim portion increases, the height (axial length) of the rim portion is increased by an amount corresponding thereto. Therefore, as described above, the thickened rim portion and the two flange portions that are integrally protruded at both ends of the tapered tubular portion of the preform are subjected to a thickening process and a forming process by rolling. In the conventional method for manufacturing a pulley, the number of grooves in the rim portion is large, and when a so-called multi-groove pulley is manufactured, the tapered cylindrical portion that gives the rim portion is lengthened as much as necessary. A preform having a large opening diameter is used, but in that case, the following problems may occur.

That is, when performing a conventional pulley manufacturing method using a preform having a tapered cylindrical portion having a large opening diameter, a forming roller is pressed against the outer peripheral surface of the tapered cylindrical portion of the preform to form the cylindrical cylindrical portion. The material (metal) that constitutes the tapered cylinder part in the bending deformation process of the tapered cylinder part when forming the rim part consisting of the thickened cylindrical part by bending in the length direction and compressing in the length direction However, it becomes easier to flow toward the distal end side (opening side) of the taper tube portion, so that the material is excessively flowed to the distal end side portion and the base side portion becomes insufficient in the rim. There was concern that a part would be formed. In a pulley having such a rim portion, not only burrs are generated at the flange portion on the distal end side of the rim portion, but also a lack of thickness is generated at the flange portion on the base side, resulting in a significant reduction in product quality. The fear was extremely high.
Japanese Patent No. 2999449 JP 2001-263454 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that it is lightweight and excellent in the strength of the flange portion, and is provided at both ends of the rim portion. An object of the present invention is to provide a pulley manufacturing method capable of stably and reliably manufacturing a high-quality multi-groove pulley free from molding defects such as burrs and underfilling at the flange portion.

  And, as a result of the inventors' diligent research in order to solve such problems, a preform having a tapered tubular portion that gradually increases in diameter toward the opening side is used, and the tapered tubular portion of this preform is used. In contrast, the thickening process and the forming process by rolling using a forming roller are performed, and the increased thickness of the cylindrical part and both ends of the cylindrical part are integrally formed radially outward. When forming a projecting protrusion, a cylindrical rim and two projecting parts form a rim and two flanges to produce a desired pulley. At the intermediate part in the height direction of the cylinder part, a bent part is formed by bending the tip side part inward, and forming a reverse tapered cylinder shape that gradually becomes smaller in diameter toward the tip, and such a bent part is provided. Prefor By forming the rim portion and the flange portion by pressing the forming roller against the outer peripheral surface of the bent portion of the tapered tube portion, the flange portion on the tip side of the rim portion is formed. The present inventors have found that it is extremely effective in preventing the occurrence of burrs and the lack of thickness at the flange portion on the base side of the rim.

  This is because the forming roller first contacts the outer peripheral surface of the bent portion at the time of the rolling process on the tapered cylindrical portion, and then, on each outer peripheral surface of the tip side portion and the base side portion from the bent portion of the tapered cylindrical portion. The entire tapered tube portion is bent so as to have a cylindrical shape while contacting and pressing the outer peripheral surface thereof, and in the bending deformation process of such a tapered tube portion, The material constituting the tip side part of the bent portion is caused to flow toward the tip side, while the material constituting the base side part is caused to flow toward the base side. This is thought to be due to the fact that the flow balance of the material to both ends is effectively enhanced.

  That is, in the present invention, which has been completed based on such knowledge, the first aspect thereof is a disk-like base portion attached to a predetermined rotating shaft, and the base portion. A cylindrical rim portion around which the belt is wound, and two flange portions integrally projecting radially outward from both axial end portions of the rim portion. In order to manufacture a pulley having a base, a disc-shaped bottom corresponding to the base of the pulley, and a diameter gradually increasing toward the opening, which is integrally extended from the outer peripheral edge of the bottom A first mold and a second mold that are positioned coaxially and rotatably about a central axis, using a bottomed tapered tubular preform comprising a tapered tubular portion that The preform is clamped coaxially between the preform and the preform. In a state where the first and second molds and their central axes are integrally rotated, a molding roller is pressed against the outer peripheral surface of the tapered cylindrical portion of the preform so that the tapered cylindrical portion becomes a cylindrical shape. While bending, it compresses in the length direction to form a thickened cylindrical part, while forming one protruding part projecting radially outward at each end of the thickened cylindrical part In the method of manufacturing the desired pulley by forming the rim portion and the two flange portions by the cylindrical portion and the two protruding portions by performing the rolling process, A taper roller having a taper-shaped outer peripheral surface gradually increasing in diameter from the base side to the tip side of the taper tube portion in a position opposite to the taper tube portion of the reform is used. Rolling process Prior to implementation, the preform is clamped at the bottom so as to be coaxially positioned between the first mold and the second mold, and the first and second molds and the The taper roller is pressed against the outer peripheral surface of the tip side portion of the preformed cylindrical portion of the preform in a state of being integrally rotated about the central axis of the preform, and the tip side portion is bent inward, thereby After forming a bent portion having an inverted tapered cylindrical shape that gradually becomes smaller in diameter toward the distal end side toward the distal end side, the forming roller is formed on the outer peripheral surface of the bent portion with respect to the outer peripheral surface of the bent portion. The method of manufacturing a pulley is characterized in that the rolling process is performed on the tapered cylindrical portion by pressing the.

  Further, in the second aspect of the pulley manufacturing method according to the present invention, the tapered roller is pressed against the outer peripheral surface of the distal end portion of the tapered tubular portion of the preform so that the distal end portion of the tapered tubular portion is The bent portion is formed by being bent inward at an inclination angle within a range of 15 to 45 ° with respect to a straight line parallel to the central axis of the tapered cylindrical portion.

  Furthermore, in the third aspect of the method for manufacturing a pulley according to the present invention, a rolling process is performed on the tapered cylindrical portion of the preform, and the rim portion and the two flange portions are formed on the preform. After that, a groove forming roller in which a V groove forming rib formed of an annular protrusion having a V-shaped cross section is provided on the outer peripheral surface, and a preform in which the rim portion and two flange portions are formed, At the bottom, it is clamped so as to be coaxially positioned between the first mold and the second mold, and is integrally rotated around the first and second molds and their central axes. In this state, the groove forming roller is pressed against the outer peripheral surface of the rim portion of the preform to form an annular V groove corresponding to the V groove forming rib on the outer peripheral surface of the rim portion. Become.

  In one advantageous aspect of the pulley manufacturing method according to the present invention, one forming roller is pressed against the outer peripheral surface of the tapered cylindrical portion of the preform, and the rolling process is performed on the tapered cylindrical portion. In this way, the tapered cylindrical portion is formed into a thickened cylindrical portion, and a rim portion forming step for forming the rim portion and a protruding portion are integrally formed at each of both end portions of the thickened cylindrical portion. And the flange part formation process which forms two flange parts will be performed at once.

  And in the 1st aspect of the manufacturing method of the pulley according to this invention, the cylindrical part increased in thickness is performed by performing the thickening process and forming process by the rolling process with respect to the taper cylinder part of a preform. While the rim is formed by this thick cylindrical portion, a protruding portion that protrudes integrally outward in the radial direction is formed on each of both ends of the rim portion made of such a thick cylindrical portion. Then, since the rim portion is formed at the projecting portions, for example, the base side end portion of the taper tube portion of the preform is folded in half, and the base side end portion The strength of both ends of the rim portion, particularly the flange portion on the base side, can be advantageously increased as compared with the case where the bent portion is formed in the bent portion and the flange portion is formed by this bent portion. Bent part that gives such a flange part The length of the taper tube can be prevented from becoming longer than necessary, so that it is possible to advantageously reduce the weight of the preform and the entire pulley. It becomes.

  In addition, in the manufacturing method according to the present invention, prior to performing the rolling process on the tapered cylindrical part of the preform, the tip side of the tapered cylindrical part is formed by a rolling process using a tapered roller. A bent portion is formed by bending the part inwardly and forming an inversely tapered cylindrical shape that gradually becomes smaller in diameter toward the tip, and the forming roller is pressed against the outer peripheral surface of the bent portion, whereby the tapered cylindrical portion Since the rim portion and the two flange portions are formed by the rolling process and the forming process by the rolling process, as described above, the taper tube portion at the time of the rolling process is formed. During the bending deformation process, the material constituting the tapered tube portion is allowed to flow in a balanced manner on the tip side and the base side, thereby allowing the flange portion on the tip side of the rim portion to flow. Of and generation, generation of underfill in the flange portion of the rim base side is, both can be effectively and reliably prevented.

  Therefore, according to the method of manufacturing a pulley according to the present invention as described above, the flange portion is lightweight and excellent in strength, and there is no molding defect such as burrs or lacking in the flange portions provided at both ends of the rim portion. This makes it possible to manufacture a high-quality multi-groove pulley stably and reliably.

  Further, according to the second aspect of the pulley manufacturing method according to the present invention, in the bending deformation process during the rolling process of the tapered cylindrical portion of the preform, the flow balance of the material to both ends of the tapered cylindrical portion is more It can be surely and more stably increased, thereby further effectively preventing the occurrence of burrs at the flange portion on the rim end side and the occurrence of thinning at the flange portion on the rim base side. Can be done.

  Furthermore, according to the third aspect of the pulley manufacturing method according to the present invention, the V-groove around which the V-belt is wound or the V-groove where the V-rib of the V-ribbed belt comes into contact with the outer peripheral surface of the rim portion is surely and easy. A high-quality multi-groove V pulley or multi-groove V-ribbed pulley without molding defects such as burrs at the front end side portion of the rim portion and lack of thickness at the base side portion is stable and reliable. Can be manufactured.

  Hereinafter, in order to clarify the present invention more specifically, the configuration of a pulley manufacturing method according to the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 schematically shows a V-ribbed pulley (multi-groove V-pulley) to which the rotational driving force of an automobile engine is transmitted via a V-ribbed belt as an example of a pulley manufactured according to the method of the present invention. ing. As is apparent from this figure, the V-ribbed pulley 10 has a substantially bottomed cylindrical shape as a whole, and has a substantially disc-shaped base portion 12 and a substantially cylindrical rim portion 14. ing.

  An attachment hole 16 to which a cooling fan coupling or the like as a rotation shaft is attached is formed in the center portion of the base portion 12 of the V-ribbed pulley 10. On the other hand, flange portions 18 and 19 projecting outward in the radial direction and continuously extending in the circumferential direction are integrally formed at both upper and lower end portions in the axial direction of the rim portion 14. Moreover, the opening side flange part 18 formed in the edge part (upper side edge part) of the rim | limb part 14 among these two flange parts 18 and 19 is a taper cylinder shape which becomes a large diameter gradually toward upper direction. On the other hand, the base side flange portion 19 formed at the end portion (lower end portion) on the base portion 12 side of the rim portion 14 has a reverse tapered cylindrical shape that gradually increases in diameter downward. ing. Further, a plurality of (seven in this case) annular V-shaped grooves 20 that are continuous in the circumferential direction are arranged on the outer circumferential surface of the rim portion 14 in the vertical direction. Thus, in the V-ribbed pulley 10, a cooling fan coupling or the like (not shown) is inserted and fixed in the mounting hole of the base portion 12, and can be rotated integrally therewith. A V-ribbed belt (not shown) having a plurality of (here, seven) V-ribs corresponding to the V-groove 20 is wound around.

  By the way, such a V-ribbed pulley 10 is manufactured, for example, according to the following method.

  That is, first, a preform 22 having a shape as shown in FIG. 2 is prepared. The preform 22 has a generally bottomed tapered cylindrical shape as a whole, and has a substantially disk shape having a shape and a size corresponding to the base 12 of the target V-ribbed pulley 10. , A bottom portion 24 provided with a central hole 26 for providing the mounting hole 16 of the V-ribbed pulley 10, and a taper formed integrally with the outer peripheral edge portion of the bottom portion 24 and gradually increasing in diameter upward. And a cylindrical portion 28.

  In addition, as such a preform 22, for example, as long as it is made of an integrated product obtained from an annular metal plate material, any ready-made product or specially molded product may be used. However, when the preform 22 is formed, for example, a punch having an outer peripheral surface corresponding to the inner surface shape of the preform 22 and a die hole having an inner peripheral surface corresponding to the outer surface shape of the preform 22 are formed. Using the provided die, drawing the annular metal plate material, or performing a known press bending process other than the drawing process or a rolling process using a predetermined rolling roller Techniques are adopted as appropriate. The material of the annular metal plate material that provides the preform 22 is appropriately selected from those conventionally used as the constituent material of the intended V-ribbed pulley 10.

  Then, by rolling the tapered cylindrical portion 28 of the preform 22 to form the rim portion 14 and the opening side and base side flange portions 18 and 19, the intended V-ribbed pulley 10 can be obtained. In the method of the present invention, in particular, first, a preforming process is performed by a rolling process on the tapered cylindrical part 28 of the preform 22, and then the preformed tapered cylinder part 28 is subjected to The forming process by the rolling process for the tapered cylinder part 28 that forms the rim part 14 and the flange parts 18 and 19 is performed.

  Here, the preforming process for the tapered cylindrical portion 28 of the preform 28 and the forming process for forming the rim portion 14 and the flange portions 18 and 19 are performed by rolling as shown in FIG. 3, for example. This is done using the device 32.

  As is apparent from FIG. 3, the rolling device 32 includes a molding die 36 installed on a base 34. Further, the molding die 36 has the same structure as the molding die provided in the pulley manufacturing apparatus disclosed in Japanese Patent Laid-Open No. 2001-263454, and has the same mounting structure on the base 34. Is installed.

  That is, the molding die 36 includes an upper die 38 as a first die and a lower die 40 as a second die that are coaxially opposed to each other in the vertical direction. It is mounted on the base 34 of the rolling device 32 so as to be immovable and rotatable around the central axis 41, and rotates around the central axis 41 as the motor 48 installed on the base 34 is driven. It is supposed to be squeezed. On the other hand, the upper die 38 can be rotated around the central axis 41 with respect to the moving plate 46 that is moved up and down by the operation of the cylinder 44 while being guided by a plurality of guide posts 42 erected on the base 34. The lower plate 40 is moved toward and away from the lower die 40 in accordance with the downward / upward movement of the moving plate 46 and is aligned with the lower die 40 by the close movement to the lower die 40. Thus, when the motor 48 is driven, both the lower die 40 can be rotated integrally around the central axis 41.

  Thus, in such a molding die 36, the preform 22 is sandwiched between the upper die 38 and the lower die 40 so as to be coaxially positioned at the bottom portion 24 between them. In addition, by driving the motor 48 in such a sandwiched state, the preform 22 can be rotated together with the upper mold 38 and the lower mold 40 around the central axis thereof.

  As shown in FIG. 4, in the lower mold 40 of the molding die 36, a V-shaped cross section is formed on the outer peripheral portion of the upper surface of the lower mold side pad 50 that constitutes the lower clamping surface with respect to the bottom 24 of the preform 22. A lower mold-side annular groove 52 having a shape and having both side surfaces corresponding to the outer surface and the front end surface of the base-side flange portion 19 of the target V-ribbed pulley 10 is formed. On the other hand, in the upper die 38, the lower outer peripheral surface of the upper die side pad 54 that constitutes the upper clamping surface with respect to the bottom 24 of the preform 22 has a shape corresponding to the inner peripheral surface of the rim portion 14 of the V-ribbed pulley 10. In addition, the outer periphery of the upper die side pad 54 has a V-shaped cross section on the inner periphery of the lower surface of the guide bush 56 positioned so as to surround the upper die side pad 54, and both side surfaces of the V-ribbed pulley 10. An upper mold side annular groove 58 having a shape corresponding to the outer surface and the front end surface of the opening side flange portion 18 is formed.

  Further, as apparent from FIG. 3, in the rolling device 32 in which the molding die 36 is installed, the roller is disposed at a position facing the molding die 36 on the outer periphery of the base 34 with the molding die 36 therebetween. The pressurizing cylinders 60a and 60b are disposed in a fixed position in a state where the piston rods 62a and 62b can be protruded / retracted in the horizontal direction toward the upper mold side pad 54 in the upper mold 38 of the molding die 36. Has been. Further, clamps 64a and 64b having a U-shaped cross section are fixed to the distal ends of the piston rods 62a and 62b of the roller pressure cylinders 60a and 60b, respectively. Then, two types of rolling rollers, a tapered roller 66 and a forming roller 68, are respectively connected to the clamps 64a and 64b of the roller pressure cylinders 60a and 60b. It is attached so that it can rotate around.

  The clamps 64a and 64b to which the taper roller 66 and the forming roller 68 are attached have a structure in which the rollers 66 and 68 can be attached and detached. Instead of any one of the taper roller 66 and the forming roller 68, a groove is provided. The forming roller 70 can be easily attached in a state where the forming roller 70 can rotate around a rotation axis parallel to the central axis 41 of the molding die 36 (see FIG. 9).

  Of these three types of rolling rollers 66, 68, 70, the tapered roller 66 is a tapered cylindrical outer peripheral surface that gradually increases in diameter toward the upper side, in other words, the upper die 38 of the molding die 36. A taper cylinder that gradually increases in diameter from the bottom 24 side to the tip opening side of the taper cylinder portion 28 of the preform 22 under the opposing arrangement with the preform 22 sandwiched between the lower mold 40 and the lower mold 40. (See FIG. 6). On the other hand, the molding roller 68 has a cylindrical surface shape corresponding to the outer peripheral surface of the rim portion 14 of the target V-ribbed pulley 10 at the intermediate portion in the height direction of the outer peripheral surface, and the upper and lower end portions thereof are the rim portion. 14 corresponds to the inner surface shapes of the opening side and base side flange portions 18 and 19 provided at both ends (see FIGS. 7 and 8). Further, the groove forming roller 70 includes a plurality of V groove forming ribs 72 extending continuously in the circumferential direction on the outer peripheral surface, and having a V-shaped cross section corresponding to the V groove 20 of the V ribed pulley 10 and arranged in the vertical direction. (7 here) is provided (see FIG. 9).

  In the taper roller 66, the forming roller 68, and the groove forming roller 70, the piston rods 62a and 62b in the roller pressurizing cylinders 60a and 60 protrude while attached to the clamps 64a and 64b. By being actuated, it can be pressed against the outer peripheral surface of the tapered cylindrical portion 28 of the preform 22 sandwiched between the upper mold 38 and the lower mold 40 of the molding die 36. These three types of rolling rollers 66, 68, 70 are in the opposite direction to the preform 22 due to contact with the tapered cylindrical portion 28 under integral rotation with the upper mold 38 and the lower mold 40 of the preform 22. Will be rotated.

  Therefore, when the desired V-ribbed pulley 10 is manufactured using the rolling device 32 having such a structure, for example, first, as shown in FIG. The lower mold 40 is in contact with the lower mold side pad 50 of the lower mold 40 and the upper mold side pad 54 of the upper mold 38, and is positioned coaxially with the lower mold 40 and the upper mold 38. It is clamped between the upper die 38 so as to be integrally rotatable around the central axis 41. Then, under such an arrangement of the preform 22, the motor 48 attached to the base 34 is driven to rotate, so that the preform 22, together with the upper mold 38 and the lower mold 40, around the central axis 41 thereof. Can be rotated together.

  Here, as will be described later, since a large number of V-grooves 20 are formed in the rim portion 14 formed by compressing and increasing the thickness of the tapered cylindrical portion 28 of the preform 22, the preform 22 is formed by the upper die 38. A preform having a tapered cylindrical portion 28 having a length dimension sufficiently larger than the distance between the lower surface of the guide bush 56 and the upper surface of the lower mold side pad 50 in a state of being sandwiched between the lower mold 40 and the lower mold 40. 22 is selected and used in particular, but the tapered cylindrical portion 28 of such a preform 22 is formed on the guide bush 56 under the set condition as described above to the molding die 36 of the preform 22. Between the lower surface and the outer peripheral portion of the upper surface of the lower mold side pad 50, the inner peripheral surface is opposed to the lower outer peripheral surface of the upper mold side pad 54, and the diameter is gradually increased upward. In state, And thus it is allowed to location.

  Next, the piston rod 62a of the roller pressure cylinder 60a attached to the base 34 is operated to protrude, and the taper roller 66 attached rotatably to the tip of the piston rod 62a is moved to the upper die side pad 54 of the upper die 38. 6, as shown by a two-dot chain line in FIG. 6, the outer peripheral surface of the taper roller 66 is integrally rotated around the central axis 41. Side) The outer peripheral surface of the part is brought into contact. At this time, the taper roller 66 is also rotated in the direction opposite to the preform 22 around its rotation axis.

  Thereafter, as shown by a solid line in FIG. 6, the tapered roller 66 is further moved closer to the upper mold side pad 52, so that the tip side portion of the tapered cylindrical portion 28 of the preform 22 is brought into contact with the outer peripheral surface of the tapered roller 66. And pressed inward in the radial direction. As a result, a bent portion 74 is formed at the intermediate portion in the height direction of the tapered tube portion 28 so as to bend the portion closer to the tip side inward. The tip portion of the tapered tube portion 28 is directed toward the tip side. The inner tapered portion 76 is inclined inwardly with an inversely tapered cylindrical shape that gradually decreases in diameter, while the portion closer to the base side than the bent portion 74 of the tapered cylindrical portion 28 gradually increases in diameter toward the distal end side. The outer tapered portion 78 is inclined outward with a cylindrical shape.

  In addition, although the inner taper part 76 made into the reverse taper cylinder shape of the taper cylinder part 28 formed at this process is not specifically limited, the central axis (41) of the taper cylinder part 28 is not limited. It is desirable to have an inversely tapered cylindrical shape that is inclined inward with an inclination angle θ in the range of 15 to 45 ° with respect to a straight line m parallel to. This is because, in the method of the present embodiment, as will be described later, a bent portion 74 is formed in the middle portion in the height direction of the tapered cylindrical portion 28 so that the tip side portion thereof is an inner tapered portion 76 having a reverse tapered shape. By using the preform 22, the flow balance of the constituent material (metal) of the tapered cylindrical portion 28 to both ends is formed in the formation of the rim portion 14 and the two flange portions 18 and 19 by rolling the tapered cylindrical portion 28. In the case where the inclination angle θ of the inner taper portion 76 is less than 15 ° or greater than 45 °, the rim portion 14 and the flange portions 18 and 19 are increased. This is because the effect of improving the flow balance to the both end sides of the constituent material of the tapered cylindrical portion 28 at the time of forming is not sufficiently obtained.

  Further, the formation position of the bent portion 74 with respect to the tapered cylindrical portion 28 is not limited at all, and for example, although it is appropriately determined depending on the size of the opening side and the base side flange portions 18 and 19, As described above, when the rim portion 14 and the flange portions 18 and 19 are formed, the bent portion 74 is advantageously provided with the tapered tube portion 28 in order to reliably increase the flow balance of the constituent materials of the tapered tube portion 28 to both ends. With respect to the length n of the entire portion 28 (see FIG. 5), the taper tube portion 28 is formed at a position deviated by a value within a range of 20 to 50% from the distal end surface to the base side.

  Next, the piston rod 62a to which the taper roller 66 is attached is retracted and operated while being integrally rotated around the central axis 41 of the preform 22, and the taper roller 66 is separated from the taper cylindrical portion 28 of the preform 22, The piston rod 62b with the forming roller 68 attached to the tip thereof is operated to project, and the forming roller 68 is brought close to the upper mold side pad 54, whereby the outer peripheral surface of the forming roller 68 is shown in FIG. The axial intermediate portion is brought into contact with the outer peripheral surface of the bent portion 74 of the tapered cylindrical portion 28 of the preform 22 that is integrally rotated around the central axis 41. At this time, the forming roller 68 is also rotated in the direction opposite to the preform 22 around its rotation axis.

  Subsequently, as shown by a two-dot chain line in FIG. 7, as the forming roller 68 is further moved closer to the upper mold side pad 52, the bent portion 74 of the tapered cylindrical portion 28 in the preform 22 is By pressing radially inward on the outer peripheral surface of the intermediate portion of the molding roller 68, the inner peripheral surface of the tapered cylinder portion 28 approaches the inner peripheral surface of the lower end portion of the upper mold side pad 50 of the upper die 38. The entire taper tube portion 28 is bent, and the tip end portion of the inner taper portion 76 of the taper tube portion 28 and the base side end portion of the outer taper portion 78 are provided on the lower surface of the guide bush 56 of the upper die 38. The upper mold side annular groove 58 and the lower mold side annular groove 52 provided on the upper surface of the lower mold side pad 50 of the lower mold 40 respectively enter the upper mold side and the lower mold side annular groove. Bent in the state engaged with the sides of 58 and 52 74 opening angle is gradually increased, the tapered tube portion 28 is deformed so as to approach the cylindrical shape.

  At this time, the forming roller 68 is first brought into contact with the outer peripheral surface of the bent portion 74 of the tapered cylindrical portion 28, and then the inner tapered portion 76 and the outer tapered portion positioned above and below the bent portion 74 of the tapered cylindrical portion 28. The taper portions 78 are brought into contact with the respective outer peripheral surfaces and pressed against the outer peripheral surfaces to bend and deform so that the entire tapered tube portion 28 has a cylindrical shape. Along with the bending deformation, the material (metal) constituting the inner tapered portion 76 is caused to flow toward the distal end side of the tapered cylindrical portion 28, while the material constituting the outer tapered portion 78 is the base portion of the tapered cylindrical portion 28. The components of the tapered tube portion 28 are caused to flow toward the both ends of the tapered tube portion 28 in a balanced manner.

  Then, as shown in FIG. 8, when the forming roller 68 is further moved closer to the upper mold side pad 52, the intermediate portion in the height direction including the bent portion 74 in the tapered cylindrical portion 28 of the preform 22 is obtained. The upper die side pad 52 is sandwiched between the outer peripheral surface of the upper pad 52 and the intermediate outer peripheral surface of the forming roller 68, and the tip end portion (upper end portion of the inner tapered portion 76) and the base end portion ( The lower end portion of the outer taper portion 78) is between the upper die-side annular groove 58 of the guide bush 56 and the outer peripheral surface of the upper end portion of the forming roller 68, and the lower die-side annular groove 52 and the forming roller of the lower die-side pad 50. 68 is pinched between the outer peripheral surface of the lower end portion of 68. At this time, the distal end side end surface and the base end side end surface of the tapered cylindrical portion 28 are brought into contact with the respective side surfaces of the upper mold side annular groove 58 and the lower mold side annular groove 52, so that a forming roller 68 for the tapered cylinder portion 28 is formed. As a result, the taper tube portion 28 is prevented from expanding in the axial direction.

  As a result, the taper tube portion 28 is compressed in the height direction (length direction), and the intermediate portion in the height direction of the taper tube portion 28 is increased by an amount corresponding to the amount of compression with respect thereto, and the upper die The rim portion 14 is formed by the cylindrical portion having the inner peripheral surface corresponding to the outer peripheral surface of the side pad 54 and the intermediate portion outer peripheral surface of the forming roller 68. At the same time, the tapered cylindrical portion 28 has a tip end portion having an outer peripheral surface and an end surface corresponding to the outer peripheral surface of the upper end portion of the forming roller 68 and the upper mold side annular groove 58 of the guide bush 56. The opening side flange portion 18 is formed at the protruding portion, and the base side end portion of the tapered cylindrical portion 28 is formed on the forming roller 68. The outer peripheral surface of the lower end portion and the inner and outer surfaces and end surfaces corresponding to both side surfaces of the lower annular groove 52 of the lower die side pad 50 are formed as protruding portions that integrally protrude radially outward of the tapered cylindrical portion 28. Thus, the base side flange portion 19 is formed by the protruding portion.

  In this step, as described above, when the rim portion 14 and the opening side and base side flange portions 18 and 19 are formed, the respective constituent materials of the inner tapered portion 76 and the outer tapered portion 78 in the tapered cylindrical portion 28 are used. Is caused to flow in a balanced manner toward both end sides of the tapered cylindrical portion 28, so that when the opening side and base side flange portions 18 and 19 are formed, the upper mold side annular groove 58 of the guide bush 56 and the upper end portion of the forming roller 68 are formed. Between the outer peripheral surface and between the lower mold side annular groove 52 of the lower mold side pad 50 and the outer peripheral surface of the lower end portion of the forming roller 68, the constituent materials of the inner tapered portion 76 and the outer tapered portion 78 are excessive. It is possible to advantageously prevent burrs, undercuts and the like from occurring in the opening side and base side flange portions 18 and 19 which are sufficiently filled without being deficient.

  Next, the piston rod 62b to which the forming roller 68 is attached is retracted to move the forming roller 68 away from the preform 22, while the piston rod 62a to which the groove forming roller 70 is attached instead of the taper roller 66. , And the groove forming roller 70 is brought close to the upper mold side pad 54. As a result, as shown in FIG. 9, the groove forming roller 70 is brought into contact with the rim portion 14 of the preform 22 that is integrally rotated around the central axis 41, and is rotated in the opposite direction to the preform 22. The outer peripheral surface is pressed against the outer peripheral surface of the rim portion 14.

  As the groove forming roller 70 further moves toward the upper mold side pad 54, the outer peripheral surface of the rim portion 14 of the preform 22 is gradually and strongly pressed by the outer peripheral surface of the groove forming roller 74. Thus, a plurality of annular V grooves 20 corresponding to the plurality of V groove forming ribs 72 provided on the outer peripheral surface of the groove forming roller 70 are formed on the outer peripheral surface of the rim portion 14. Thus, a disc-shaped base 12 provided with a mounting hole 16 to which a cooling fan coupling or the like is attached at the center and a plurality of V grooves 20 with which the V ribs of the V ribbed belt are brought into contact with each other are formed on the outer peripheral surface. It has a cylindrical rim portion 14 and an opening side and base side flange portions 18 and 19 that project radially outward from both end portions of the rim portion 14 in the axial direction. A V-ribbed pulley 10 is obtained.

  Then, after that, the cylinder 44 provided on the base 34 is retracted to move the upper die 38 upward as shown in FIG. 10, and the molding die 36 is opened. Below, the V-ribbed pulley 10 obtained as described above is discharged from the upper die 38 and released from the molding die 36.

  Thus, according to the manufacturing method of the V-ribbed pulley 10 according to the present embodiment, the forming roller for the tapered cylindrical portion 28 of the preform 22 for forming the rim portion 14 and the opening side and base side flange portions 18 and 19. At the time of rolling using 68, the flow balance to the both end sides of the constituent material of the tapered cylindrical portion 28 is increased, so that the opening side and base side flange portions 18 and 19 formed at both end portions of the rim portion 14 Therefore, a high-quality multi-groove pulley free from molding defects on the opening side and base side flange portions 18 and 19 can be advantageously prevented. It can be manufactured stably and reliably.

  In addition, in the present embodiment method, the opening side and the base side flanges 18 and 19 are respectively formed on the projecting portions integrally formed at both ends of the thickened cylindrical portion that is an intermediate portion of the tapered cylindrical portion 28. Compared to the case where the flange portion 19 is formed, for example, by making the length of the tapered tube portion 28 longer than necessary and folding a part thereof in half. Thus, not only the strength of the opening side and base side flange portions 18 and 19 can be effectively increased, but the entire length of the V-ribbed pulley 10 can be increased to the extent that it is not necessary to increase the length of the tapered cylindrical portion 28 more than necessary. Weight reduction can be advantageously achieved.

  Further, in this embodiment method, the taper tube portion 28 of the preform 22 is intermediate in the height direction of the taper tube portion 28 by performing only one rolling process using a single forming roller 68. The portion is a thickened cylindrical portion, and projecting portions are integrally formed at both ends of such a thickened cylindrical portion, and the rim portion 14 and the opening side are formed by the thickened cylindrical portion and the two protruding portions. And the base side flange portions 18 and 19 are formed at a stroke. For example, a thickening roller for increasing the thickness of the taper tube portion 28 is used to rotate the taper tube portion 28. After the taper tube portion 28 is increased in thickness by the forming process, the increased thickness of the taper tube portion 28 is further subjected to a rolling process with a predetermined forming roller, so that the rim portion 14 and the opening side and Form base flanges 18 and 19 Compared to the technique, the target V-ribbed pulley 10 can be advantageously manufactured with a small number of steps, and thus the work efficiency and productivity at the time of manufacturing the V-ribbed pulley 10 are extremely improved. Can be effectively achieved.

  Furthermore, in the manufacturing method of the V-ribbed pulley 10 of the present embodiment, the outer peripheral surface of the rim portion 14 formed at the intermediate portion in the height direction of the tapered cylindrical portion 28 of the preform 22 is rolled by the groove forming roller 70. Since a plurality of V-grooves 20 are formed at once on the outer peripheral surface of the rim portion 14 by performing the processing, the formation processing of the plurality of V-grooves 20 on the outer peripheral surface of the rim portion 14 is compared. Therefore, there is an advantage that it can be carried out quickly with a small processing force.

  The specific configuration of the present invention has been described in detail above. However, this is merely an example, and the present invention is not limited by the above description.

  For example, an apparatus for forming the bent portion 74 at the intermediate portion in the height direction of the tapered cylindrical portion 28 of the preform 22 without using the rolling device 32 as shown in the above embodiment, and the bent portion 74 are formed. A device for forming the rim portion 14 and the opening side and base side flange portions 18 and 19 from the tapered cylindrical portion 28 and a device for forming a plurality of V grooves 20 on the outer peripheral surface of the rim portion 14 are separately used. It is also possible to manufacture the target V-ribbed pulley 10 from the preform 22 in stages.

  Further, in the above-described embodiment, the intermediate portion in the height direction of the tapered cylindrical portion 28 is increased by simply performing a single rolling process on the tapered cylindrical portion 28 of the preform 22 using a single forming roller 68. And the protrusions are integrally formed at both ends of such a thickened cylindrical portion, and the rim portion 14 and the opening side and base side flange portions are formed by the thickened cylindrical portion and the two protruding portions. 18 and 19 are formed at once. For example, as described in Japanese Patent No. 2999449, a first forming roller (thickening roller) for increasing the thickness of the tapered cylindrical portion 28 is used. The taper tube portion 28 is made to be a thickened cylindrical portion by performing a thickening process by rolling on the tapered tube portion 28, and then the taper tube portion 28 is made to be a thickened cylindrical portion. , The first forming roller Rolling process is further performed by a second forming roller that is separate from (a), and one projecting portion projecting radially outward is formed at each end of the thickening cylindrical portion. The rim portion 14 and the opening side and base side flange portions 18 and 19 may be formed by the portion and the two protruding portions.

  Further, the shape of the upper die 38 as the first die and the lower die 40 as the second die, and further the shape of the molding roller 68 are not limited to those shown in the above embodiment. It can be appropriately changed according to the shape of the rim portion 14 and the opening side and base side flange portions 18 and 19.

  In addition, in the above embodiment, a specific example of applying the present invention to a method for manufacturing a V-ribbed pulley in which the rotational driving force of an automobile engine is transmitted via a V-ribbed belt is shown. Other than such a V-ribbed pulley, a disc-shaped base portion attached to a predetermined rotating shaft, a cylindrical rim portion around which the belt is wound, and radially outward from both ends of the rim portion. Of course, the present invention can be advantageously applied to any method of manufacturing a pulley having two flange portions projecting from each other.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is longitudinal cross-sectional explanatory drawing which shows an example of the pulley manufactured according to this invention method. It is a longitudinal cross-sectional explanatory drawing of the preform shape | molded from the metal plate raw material used in order to manufacture the pulley shown by FIG. It is explanatory drawing which shows one process example in the manufacturing method of the pulley according to this invention, Comprising: The state which set the preform to the rolling apparatus used in this manufacturing method is shown. It is a longitudinal cross-sectional explanatory drawing which shows an example of the shaping die used in the manufacturing method of the pulley according to this invention. It is explanatory drawing which shows another process example in the manufacturing method of the pulley according to this invention, Comprising: The preform was pinched | interposed between the upper mold | type and the lower mold | type, and the state rotated integrally about the central axis is shown. . It is explanatory drawing which shows another process example in the manufacturing method of the pulley according to this invention, Comprising: The taper cylinder part of a preform is pressed with a taper roller, A bending part is provided in the intermediate part of the height direction of this taper cylinder part. The formed state is shown. It is explanatory drawing which shows the other example of a process in the manufacturing method of the pulley according to this invention, Comprising: The state which made the forming roller contact the outer peripheral surface of the bending part formed in the taper cylinder part of a preform is shown. It is explanatory drawing which shows the further example of a process in the manufacturing method of the pulley according to this invention, Comprising: The bending part of the taper cylinder part was pressed with the forming roller, and the rim | limb part, the opening side, and the base side flange part were formed. Indicates the state. It is explanatory drawing which shows another example of a process in the manufacturing method of the pulley according to this invention, Comprising: The rim part is pressed with the groove | channel formation roller, The state which formed the several V groove in the outer peripheral surface of a rim part is shown. . It is explanatory drawing which shows another example of a process in the manufacturing method of the pulley according to this invention, Comprising: The manufactured pulley is shown in the state released.

Explanation of symbols

10 V-ribbed pulley 12 Base portion 14 Rim portion 18 Open side flange portion 19 Base side flange portion 20 V groove 22 Preform 24 Bottom portion 28 Tapered cylinder portion 32 Rolling device 36 Molding die 38 Upper die 40 Lower die 52 Lower die side annular groove 58 Upper mold side annular groove 66 Tapered roller 68 Forming roller 70 Groove forming roller 74 Bent part 76 Inner taper part 78 Outer taper part

Claims (3)

A disc-shaped base portion attached to a predetermined rotating shaft, a cylindrical rim portion integrally formed on the outer peripheral edge portion of the base portion, around which a belt is wound, and radial directions from both axial end portions of the rim portion When manufacturing a pulley having two flange portions integrally projecting outward, a disc-shaped bottom portion corresponding to the base portion of the pulley and an outer peripheral edge portion of the bottom portion are integrated. The bottom of the preform is rotated coaxially and around the central axis using a preform with a bottomed taper that is extended to the opening and gradually tapers toward the opening. Coaxially sandwiched between the first mold and the second mold that are positioned so that the preform is integrally rotated with the first and second molds around their central axes. And forming on the outer peripheral surface of the tapered cylindrical portion of the preform. While pressing the roller to bend the tapered cylindrical part into a cylindrical shape, it is compressed in the length direction to form a thickened cylindrical part, while both ends of the thickened cylindrical part are The rim portion and the two flange portions are formed by the cylindrical portion and the two protruding portions by performing a rolling process in which the protruding portions protruding outward in the radial direction are respectively formed on the portions. Then, in the method of manufacturing the target pulley,
Using a taper roller having a tapered outer peripheral surface that gradually increases in diameter from the base side to the tip side of the taper tube portion, facing the taper tube portion of the preform, the taper tube portion of the preform Prior to performing the rolling process on the preform, the preform is sandwiched between the first mold and the second mold at the bottom so as to be positioned coaxially, By pressing the taper roller against the outer peripheral surface of the tip side portion of the tapered cylindrical portion of the preform in a state where the second die and the central die are integrally rotated, the tip side portion is bent inward. After forming a bent portion having a reverse tapered cylindrical shape that gradually becomes smaller in diameter toward the distal end side of the tapered tube portion toward the distal end side, the bent portion is formed outside the bent portion. By pressing the forming roller relative to the surface, a manufacturing method of the pulley, characterized in that to perform the rolling process with respect to the tapered tube portion.   By pressing the taper roller against the outer peripheral surface of the tip side portion of the taper tube portion of the preform, the tip side portion of the taper tube portion is 15 to 45 ° with respect to a straight line parallel to the central axis of the taper tube portion. The pulley manufacturing method according to claim 1, wherein the bent portion is formed by bending inwardly with an inclination angle within the range. A V-groove forming rib comprising an annular ridge having a V-shaped cross section after forming the rim portion and the two flange portions on the preform by rolling the tapered tubular portion of the preform. Using a groove forming roller provided on the outer peripheral surface, and the preform formed with the rim portion and the two flange portions is coaxially arranged between the first die and the second die at the bottom portion. By pressing the groove forming roller against the outer peripheral surface of the rim portion of the preform in a state where the first and second molds and the central die are rotated integrally with each other. The pulley manufacturing method according to claim 1 or 2, wherein an annular V groove corresponding to the V groove forming rib is formed on the outer peripheral surface of the rim portion.

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