JP2006218496A - Method for manufacturing pulley for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a pulley at the load lower than the load during the forging by the conventional manufacturing method. <P>SOLUTION: The method for manufacturing the pulley includes a step of forming an intermediate-shaped pulley having the flange outside diameter (the first enlarged diameter) L1 which is larger than the blank diameter L0 in forging steps from 1(B) to (D) in the figures. The method further includes a step of applying the pressure from front and back faces of a flange part of the intermediate-shaped pulley. In this step, the pressure is locally applied to a part in the circumferential direction of the flange part of the intermediate-shaped pulley, and a pressure-applied part is successively moved in the circumferential direction of the flange part. As a result, a flange part having the second enlarged diameter L2 in which the outside diameter (the first enlarged diameter) of the intermediate-shaped flange part is further enlarged. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a pulley used in a transmission capable of adjusting a gear ratio steplessly.

As schematically shown in FIG. 7, the continuously variable transmission 100 transmits torque from the drive shaft 120 to the driven shaft 122 via the endless belt 113, and can adjust the gear ratio steplessly. .
The fixed pulley 110 is fixed to the drive shaft 120 so as not to be relatively rotatable and cannot be moved in the axial direction, and the movable pulley 111 is guided so as to be relatively unrotatable and movable in the axial direction. A fixed pulley 123 is fixed to the driven shaft 122 so as not to be relatively rotatable and axially movable, and a movable pulley 124 is guided so as to be relatively nonrotatable and movable in the axial direction.
A cylinder portion 114 is formed on the back side of the flange portion 111a of the movable pulley 111 on the drive side. A partition wall member 150 is inserted inside the cylinder portion 114, and an oil chamber 160 is formed by the cylinder portion 114, the partition wall member 150, and the movable pulley 111. A similar oil chamber 125 is also formed on the back surface of the driven movable pulley 124.
The endless belt 113 passes between the flange portion 110a of the drive-side fixed pulley 110 and the flange portion 111a of the movable pulley 111, and between the flange portion 123a of the driven-side fixed pulley 123 and the flange portion 124a of the movable pulley 124. Has passed.
When the hydraulic pressures of the drive-side oil chamber 160 and the driven-side oil chamber 125 are increased or decreased in synchronization, the axial positions of the drive-side movable pulley 111 and the driven-side movable pulley 124 move synchronously. The rotational radius of the endless belt 113 on the drive shaft 120 and the driven shaft 122 can be changed steplessly by synchronously moving the axial positions of the drive-side movable pulley 111 and the driven-side movable pulley 124. The gear ratio can be changed steplessly.

  A combination of a fixed pulley and a movable pulley may be referred to as a pulley, but in this specification, each is referred to as a pulley. Moreover, the substantially disk-shaped part which an endless belt contacts is called a flange part, the side where an endless belt contacts is called a surface, and the side where an endless belt does not contact is called a back surface. The fixed pulley may be formed integrally with the shaft. The flange portion is rotationally symmetric around the shaft and extends radially and axially.

  In order to ensure a large variable range of the gear ratio, it is necessary to increase the diameter (outer diameter) of the flange portion. In order to transmit a large torque, the pulley is required to have a high strength. A continuously variable transmission requires a large diameter and high strength pulley.

FIG. 8 shows a conventional method for forming a large-diameter and high-strength pulley. In FIGS. 8 and 9, only the right half of the longitudinal section of the pulley is shown for simplicity.
In the method shown in FIG. 8, all of the illustrated steps are performed using a forging die. FIG. 8A shows a columnar material 201 before processing. Then, the forging die is changed in order from (B) to (F) in FIG. At the stage of FIG. 8E, a flange portion 205a that has been expanded to a predetermined outer diameter L2 and a cylinder portion 205b that has a predetermined design dimension are formed. And the hole which inserts a shaft is formed by the forge process from FIG.8 (E) to FIG.8 (F). Thus, forging of the pulley 206 having the flange portion 206a expanded to a predetermined outer diameter L2 and the cylinder portion 206b having a predetermined design dimension is completed.

  In addition, since high precision is required for pulleys, machine cutting such as outer diameter finishing is required after forging, but the outer diameter cannot be increased by machine cutting. Therefore, it is necessary to make the outer diameter slightly larger than the outer diameter of the flange portion of the final product.

In the method shown in FIG. 8, since the forging die is used for forming, portions having the same radius can be formed simultaneously. Compared with a molding technique that sequentially molds portions having the same radius in the circumferential direction, molding can be performed in a short time because molding can be performed simultaneously.
However, on the other hand, the molding load is high because molding is performed simultaneously. In particular, as the diameter of the flange portion increases, the molding load increases, and a very large molding load is required in the molding stage shown in FIGS. 8D to 8E. Therefore, the manufacturing equipment cost of the continuously variable transmission pulley increases.

In order to solve this problem, the technique of Patent Document 1 has been proposed. FIG. 9 illustrates the forming method. The shape shown in FIG. 9A is formed by the same forging process as in FIG. FIG. 9A shows a state in which the outer diameter of the flange portion 207a is expanded to a predetermined dimension L2 by this forging process. However, in this forging process, a thick portion 207c is formed on the outer peripheral portion of the finally forged flange portion 207a, not the shape corresponding to the cylinder portion. In FIG. 9B, the cylinder portion 206b having a predetermined design dimension is formed by spinning the thick portion 207c. In addition, a fixed pulley can be manufactured if it forges so that the thick part 207c may not remain at the time of forging of FIG. 9 (A). A shaft-integrated fixed pulley can also be manufactured by the same forging method.
According to this method, a forging die for forming the cylinder portion 206b is not required, and part of a large forging facility can be eliminated.

  Patent Document 2 discloses a method of forming a pulley without forging. In this technique, an upper indenter having a molding surface recessed in a cone shape is locally pressed against an end surface of a cylindrical material in which the fiber flow extends in the axial direction. By rotating the upper indenter pressed against the material while swinging, the fiber flow of the material flows in a spiral shape, and the material is formed into a large diameter and cone shape. At this time, extra material is guided to the outer peripheral portion of the pulley to increase the thickness, and the thick portion is later swaging into a thin cylindrical shape to form the cylinder portion.

JP 2000-310305 A (see paragraphs 0038 to 0043 and FIGS. 1 and 3 of the publication) Japanese Patent Laid-Open No. 11-182641 (see paragraphs 0010 to 0018 and FIGS. 2 to 9)

In the method of Patent Document 1 shown in FIGS. 8 and 9 and the like, forging using a forging die, positions of the same radius can be processed simultaneously, and molding can be performed in a short time. On the other hand, the molding load is high and the equipment costs increase.
On the other hand, in the technique of Patent Document 2, since the processing position is sequentially moved in the circumferential direction by rotating while rotating the upper mold indenter pressed against the cylindrical material, There is an advantage that the molding load is low. However, since the processing position is sequentially moved in the circumferential direction from a cylindrical material to a predetermined flange diameter, there is a problem that molding cannot be performed in a short time.
The present invention proposes a technique for enjoying the advantages of both and overcoming the disadvantages. That is, an object of the present invention is to realize a manufacturing method capable of manufacturing a pulley for a continuously variable transmission in a short time with inexpensive equipment.

The present invention relates to a method of manufacturing a pulley for a continuously variable transmission having a flange portion that is rotationally symmetric about an axis and that extends in the radial direction and the axial direction.
The manufacturing method according to claim 1 includes a first step of forging a small-diameter material using a forging die to form an intermediate shape pulley having an intermediate shape flange portion. The outer diameter (first enlarged diameter) of the intermediate-shaped flange is larger than the material diameter and is expanded from the material diameter.
The manufacturing method according to claim 1 further includes a step of applying pressure from both the front and back surfaces of the intermediate flange portion. Here, pressure is locally applied to a portion of the intermediate flange portion in the circumferential direction, and the pressure location is sequentially moved in the circumferential direction of the flange portion. As a result, a flange portion having a second enlarged diameter in which the outer diameter (first enlarged diameter) of the intermediate-shaped flange portion is further enlarged is formed.

According to the method of the present invention, at the stage of forging using a forging die, it is not necessary to enlarge to the second enlarged diameter, and it is sufficient to enlarge to a first enlarged diameter smaller than that. Forging can be performed with a smaller molding load than when the diameter is increased to the second enlarged diameter, and the forging equipment can be downsized to reduce the equipment cost. In the stage of enlarging to the first enlarged diameter, the same radius portion can be formed at the same time, and it is not necessary to form with time in the circumferential direction, so that it can be formed in a short time.
After enlarging to the 1st expansion diameter, it expands to the 2nd expansion diameter by applying pressure locally to a part of the circumference direction, and moving the pressurization part sequentially in the circumference direction. In order to pressurize locally, only a small molding load is required and a large molding apparatus is not required. In order to move the pressurizing part sequentially in the circumferential direction, it takes time for the forming process, but since it is limited to the stage of expanding from the first enlarged diameter to the second enlarged diameter, It is within the allowable range.

  According to the method of the present invention, both the advantage of forming the same radius portion simultaneously by forging and forming in a short time and the advantage of requiring a small forming load to pressurize locally can be enjoyed. Since it does not forge and expand beyond the first enlarged diameter, the load required for forging does not become excessive. In order to form up to the first enlarged diameter in a short time by forging, even if a technique for sequentially moving the pressurization locations in the circumferential direction is adopted, the problem that the molding takes too much time does not become obvious. Only the advantages can be enjoyed without dragging the disadvantages of the prior art.

  In the second step, it is preferable to rotate the rotation shafts of the pair of rollers relative to the flange portion around the rotational symmetry axis of the flange portion while sandwiching the front and back surfaces of the intermediate flange portion with the pair of rollers. Each of the pair of rollers contacts the flange portion along the in-plane radiation of the flange portion. The in-plane radiation here refers to a line where the cross section including the rotational symmetry axis of the flange portion and the flange surface (surface on the side where the endless belt contacts) intersect.

When each roller is rotated with the pair of rollers sandwiching the front and back surfaces of the intermediate flange portion, the rotation shafts of the pair of rollers rotate about the rotationally symmetric axis with respect to the flange portion. The pressurization location can be sequentially moved in the circumferential direction while locally pressurizing, and simple pressurization equipment can be used. Or conversely, when the rotation shafts of the pair of rollers are rotated around the rotational symmetry axis with respect to the flange portion, the rollers rotate. If there is a drive source that rotates the roller, a drive source that rotates the roller around the rotational symmetry axis is unnecessary, and if there is a drive source that rotates the roller around the rotational symmetry axis, the drive source that rotates the roller It is unnecessary.
When rolling hot, the roller that rotates is cooled while not in contact with the flange. When rolling hot, the roller can be prevented from overheating.

  In the second step, it is preferable to induce extra material on the outer periphery of the flange portion. In this case, pressure is applied to a part of the circumferential direction of the extra material guided to the outer periphery of the flange portion from the inner peripheral side and the outer peripheral side, and the pressurization location is sequentially moved in the circumferential direction to It is preferable that a step of forming a cylinder portion by forming a cylindrical wall extending in the axial direction from the vicinity is added. The extra material here refers to a material that is unnecessary for molding the flange portion, and a material that is used to mold the cylinder portion thereafter. The step of guiding extra material to the outer periphery of the flange portion and the step of forming the cylinder portion may be performed simultaneously or at different times.

  If the above process is added, the cylinder part can be molded, so that the manufacturing process of the movable pulley can be simplified. Since the cylinder part having a large diameter is not forged, an excessive forging load is not required.

When molding up to the cylinder part, the back of the intermediate-shaped flange part is supported by a die, the flange-forming roller is pressed against the surface of the intermediate-shaped flange part, and the cylinder part forming roller is inserted into the flange part where extra material is guided. The rotation shaft of the flange portion forming roller and the rotation shaft of the cylinder portion forming roller can be rotated around the rotational symmetry axis of the flange portion with respect to the flange portion. Here, the die has an outer peripheral surface extending substantially parallel to the rotational symmetry axis of the flange portion, the flange portion forming roller contacts the surface of the flange portion along the in-plane radiation of the flange portion, and the cylinder portion forming roller is It has a rotation axis substantially parallel to the rotational symmetry axis of the flange.
According to the present invention, since the die is used for forming the flange portion and the cylinder portion, the equipment can be simplified.

According to the present invention, while the advantage of forming in a short time by forging is enjoyed, the forging to the final radius (second enlarged diameter) is not performed, so that the load required for forging does not become excessive. In order to prevent the forging load from becoming excessive, it adopts a technology that sequentially moves the pressurization points in the circumferential direction, but it has already been expanded up to the intermediate stage, so it takes too much time to form sequentially The problem is not revealed. Only the advantages of the prior art can be enjoyed.
According to the present invention, a large-diameter and high-strength pulley can be manufactured in a short time with inexpensive equipment.

The main features of the examples are listed.
(Mode 1) The first enlarged diameter is preferably about 2/3 of the second enlarged diameter.
(Mode 2) In the second step, one place in the circumferential direction may be pressurized, but it is preferable to pressurize a plurality of places simultaneously.
(Mode 3) In order to induce extra material on the outer periphery of the flange portion, the pressurizing step is continued even after the flange portion is expanded to the second enlarged diameter. At this time, a stopper is provided so that the outer diameter of the flange portion does not increase beyond the second expansion diameter. By this stopper, the material guided radially outward is guided in a direction extending along the rotational symmetry axis from the outer periphery of the flange portion to the back side of the flange portion (opposite the surface in contact with the endless belt).
(Mode 4) A thin cylindrical cylinder part is formed by pressing a material guided from the outer periphery of the flange part along the rotational symmetry axis of the flange part against the outer peripheral side surface of the die by a cylinder part forming roller.
(Mode 5) The first step may be hot forging or cold forging, but hot forging is preferred.
(Mode 6) The second step may be hot rolling or cold rolling, but hot rolling is preferred.
(Form 7) The radius of the roller which contacts a flange part along the in-plane radiation of a flange part is expanded toward the outer periphery of a flange part. The radius of the roller increases in proportion to the radius of the flange along the radius of the flange. Thus, no slip occurs between the roller and the flange portion from the inner peripheral side to the outer peripheral side of the flange portion.

Hereinafter, embodiments will be described in detail with reference to the drawings.
<First Example>
FIG. 1 illustrates a process in which a pulley is manufactured from a material by the pulley manufacturing method according to the present embodiment. In FIG. 1, only the right half of the center axis of the pulley is shown. A cylindrical member denoted by reference numeral 1 in FIG. 1A is a material before forging, and a material diameter (material outer diameter) is L0. 1 (B) to 1 (D) is a forging step A, which gradually approaches the shape of the pulley while sequentially changing the forging die. In (B), the lower outer periphery is shaped 2 and in (C), the thickened and small-diameter flange portion 3a is shaped 3. In (D), the intermediate shape 4 in which the outer diameter of the flange portion 4a is expanded to the outer diameter intermediate value (first expanded diameter) L1 is formed. The first enlarged diameter L1 is larger than the material diameter L0 and smaller than a second enlarged diameter L2 described later. The shape 4 that is forged by the final forging die and has the flange portion outer dimension of the first enlarged diameter L1 as shown in FIG.

When the forging process A is completed, the flange portion 4a of the intermediate pulley is rolled as shown in (E). The shape after rolling is a member denoted by reference numeral 5 in FIG. At this stage, the outer diameter of the flange portion 5a is expanded to the outer diameter design value (second expanded diameter) L2. The outer diameter design value L2 is larger than the first enlarged diameter L1.
In the rolling process, pressure is applied from both the front and back sides to a part in the circumferential direction of the intermediate-shaped flange portion 4a, and the pressurization location is sequentially moved in the circumferential direction, whereby the outer diameter design value L2 from the first enlarged diameter L1. Enlarge the diameter. The process of enlarging the diameter by sequentially moving the pressurization locations in the circumferential direction will be referred to as a rolling process. In the first embodiment, only the step of forming the pulley shape 5 of (E) from the shape of the intermediate shape pulley 4 of (D) in FIG. A specific example of a manufacturing apparatus that performs the rolling step B will be described later.

The load required in the forging process is approximately proportional to the area viewed from the direction in which the object to be forged is pressed against the forging die. If it is attempted to increase the outer diameter of the flange portion to the outer diameter design value L2 by the conventional manufacturing method, the load required for this is approximately proportional to the square of L2. On the other hand, the first enlarged diameter L1 to enlarge the forging process, when the 2/3 × L2, the load required is proportional to the 4/9 × L2 ^2. The load required for forging up to 2/3 × L2 is less than half of the load required for forging up to L2. If the diameter is expanded by forging to 2/3 × L2, then it is sufficient to increase the diameter by rolling by 1/3 × L2, so that the rolling time does not become excessive. If the first enlarged diameter L1 that is expanded in the forging process is approximately 2/3 of the outer diameter design value L2 that is finally expanded, the forging load does not become excessive and the rolling time does not become excessive.

  In the present embodiment, in the rolling process B, the thick portion 5c is provided on the outer peripheral portion of the flange portion. Next, the cylinder portion 6b shown in FIG. 1 (F) is formed by a processing method such as flow forming.

  Thereafter, the final product of the pulley is obtained through a heat treatment process, a machine cutting process, and the like. The final flange outer diameter of the pulley is different from L2 in FIGS. In the present invention, the flange portion outer diameter L2 before the heat treatment step and the machine cutting step is referred to as an outer diameter design value (second enlarged diameter). Moreover, the flange part of the intermediate shape pulley 4 shape | molded by the forge process is called the intermediate shape flange part 4a. Furthermore, the outer diameter L1 of the intermediate flange portion 4a is referred to as an outer diameter intermediate value (first enlarged diameter).

Next, an embodiment of an apparatus for carrying out the rolling process B described above will be described with reference to FIGS. FIG. 2 is a schematic sectional view of the apparatus. The left side of the center line in FIG. 2 shows the arrangement before the rolling process B, and the right side of FIG. 2 shows the arrangement after the rolling process B. Therefore, the left and right parts with respect to the center line in FIG. 2 indicate the same parts. FIG. 3 is a cross-sectional view of the device cross section taken along the line III in FIG. 2 as viewed in the direction of the arrow (FIG. 2 is a cross-sectional view because the operation state of the device is different on the left and right of the center line The symbol and arrow line corresponding to III ′ corresponding to III are omitted. FIG. 4 is a cross-sectional view of the device cross section taken along the line IV in FIG. 2 as viewed from the direction of the arrow IV.
The structure of the apparatus will be described with reference to the left side of the center line in FIG.
The rolling device is provided with a mandrel 10 to be inserted into the center hole of the intermediate pulley 4. A lower forming roller 13 is disposed at a position adjacent to the mandrel 10. As shown in FIG. 3, the lower forming rollers 13 are arranged at three positions at equal intervals in the circumferential direction (see 13a, 13b, and 13c). The rotation axis of the lower forming roller 13 is substantially orthogonal to the rotation axis x of the mandrel 10. The rotation shaft of the lower forming roller 13 is arranged radially about the rotation axis x of the mandrel 10. A lower support roller 14 that supports the lower molding roller 13 is disposed below the lower molding roller 13.
As shown in FIG. 4, a lower positioning roller 19 is disposed at a position adjacent to the mandrel 10. The lower positioning rollers 19 are also arranged at three positions at equal intervals in the circumferential direction (see 19a, 19b, 19c). The lower positioning roller 19 is disposed at a position where it does not interfere with the lower molding roller 13. The rotational axis of the lower positioning roller 19 is substantially parallel to the rotational axis x of the mandrel 10.

  When the center hole of the intermediate shape pulley 4 is fitted into the upper end of the mandrel 10, the back surface of the intermediate shape flange portion 4 a of the intermediate shape pulley 4 comes into contact with the lower forming roller 13. The lower forming roller 13 contacts the back surface of the intermediate shape flange portion 4a along the in-plane radiation on the back surface of the intermediate shape flange portion 4a. The inner peripheral surface of the shaft portion of the intermediate shape pulley 4 faces the outer peripheral surface of the mandrel 10. The outer peripheral surface of the shaft portion of the intermediate shape pulley 4 faces the lower positioning roller 19.

When the center hole of the intermediate pulley 4 is fitted into the upper end of the mandrel 10, the upper molding roller 11 and the upper support roller 12 that supports the upper molding roller 11 are lowered to the position shown in FIG.
As shown in FIG. 3, the upper forming roller 11 is arranged at three locations at equal intervals in the circumferential direction (see 11a, 11b, and 11c). The upper molding roller 11 is disposed at the same position in the circumferential direction as the lower molding roller 13. In other words, the upper molding roller 11 and the lower molding roller 13 form a pair to sandwich the intermediate flange portion 4a from both the front and back surfaces. The rotation axis of the upper forming roller 11 is substantially orthogonal to the rotation axis x of the mandrel 10. The rotation shaft of the upper forming roller 11 is arranged radially from the rotation axis x of the mandrel 10. In FIG. 3, the upper forming roller 11a should be a cross-sectional view similar to 11b and 11c, but hatching is omitted to facilitate the explanation of the parts underneath. An upper support roller 12 that supports the reaction force when the upper molding roller 11 presses the intermediate flange portion 4a downward is disposed above the upper molding roller 11.
When the upper molding roller 11 and the upper support roller 12 are lowered to the position shown in FIG. 2, the surface of the intermediate flange portion 4 a of the intermediate pulley 4 comes into contact with the upper molding roller 11. The upper forming roller 11 contacts the surface of the intermediate shape flange portion 4a along the in-plane radiation of the intermediate shape flange portion 4a.
The intermediate flange portion 4a is sandwiched by the upper molding roller 11 and the lower molding roller 13 from both front and back surfaces, and is pressed from both front and back surfaces. The pressurizing range is along the in-plane radiation and locally presses a part of the intermediate flange portion 4a in the circumferential direction.

The radius of the upper molding roller 11 is increased toward the outer periphery of the flange portion. That is, the radius of the upper forming roller 11 increases in proportion to the radius of the flange portion 4a along the radius of the flange portion 4a. As a result, at the position along the in-plane radiation where the flange portion 4a contacts the upper molding roller 11, the speed when the flange portion 4a rotates and the speed when the upper molding roller 11 rotates around the rotation axis are as follows. The flange portion 4a coincides from the inner peripheral side to the outer peripheral side, and no slip occurs between the upper forming roller 11 and the flange portion 4a.
The lower molding roller 13, the lower support roller 14, the lower positioning roller 19, the upper molding roller 11 and the upper support roller 12 are all rotatable. In FIG. 2, the upper forming roller 11, the upper supporting roller 12, the lower forming roller 13, the lower supporting roller 14, and the mandrel 10 also have cross-sectional shapes, but hatching for showing the cross section is omitted for easy understanding. It is.

At the stage of setting the intermediate shape pulley 4, the lower positioning roller 19 is separated from the mandrel 10, and the upper forming roller 11 and the upper support roller 12 are retracted upward. For this purpose, the center hole of the intermediate pulley 4 can be fitted into the upper end of the mandrel 10. In this state, the back surface of the intermediate flange portion 4 a is supported by the lower forming roller 13. In addition, the intermediate | middle shape pulley 4 is heated previously, and the following rolling processes become a hot rolling process.
With the start of the rolling process, the lower forming roller 13 starts to rotate in the direction of arrow b, the lower positioning roller 19 approaches toward the mandrel 10, and the upper forming roller 11 and the upper support roller 12 are lowered. The lower positioning roller 19 approaches the mandrel 10 to a predetermined distance, and the upper forming roller 11 and the upper support roller 12 are lowered to the bottom dead center height, thereby completing the rolling process.

When the lower forming roller 13 rotates in the direction of the arrow b in FIG. 2, the intermediate shape pulley 4 and the mandrel 10 rotate in the direction of the arrow a in FIG. 2 due to friction. At the same time, the upper forming roller 11 rotates by friction in the direction of the arrow c in FIG. In this state, the upper forming roller 11 applies a load downward to the intermediate-shaped flange portion 4a.
Then, the intermediate-shaped flange part 4a is pressed from both front and back surfaces by the upper molding roller 11 and the lower molding roller 13 from both front and back surfaces. The pressurizing range is along the in-plane radiation, and a portion of the intermediate flange portion 4a in the circumferential direction is locally pressurized. Even if the intermediate-shaped pulley 4 is heated for hot rolling, the upper forming roller 11 and the lower forming roller 13 that rotate are cooled while being separated from the intermediate-shaped pulley 4, and the upper forming roller 11 and the lower forming roller 11 are cooled. The roller 13 does not overheat.
The intermediate shape pulley 4 rotates in the direction of the arrow a in FIG. 2, whereas the rotation shafts of the upper forming roller 11 and the lower forming roller 13 do not move. As a result, the rotation shafts of the upper forming roller 11 and the lower forming roller 13 rotate relative to the flange portion 4a around the rotational symmetry axis x (the rotation axis of the mandrel). In the range along the in-plane radiation in which the upper molding roller 11 and the lower molding roller 13 are pressed from both the front and back surfaces, the flange portion 4a is sequentially moved in the circumferential direction.
When the pressure range is moved in the circumferential direction in a state where a part of the flange portion 4a in the circumferential direction is locally pressurized, the flange portion 4a is rolled in a direction in which the outer diameter increases.

The result of rolling the flange portion 4a of the intermediate pulley 4 is shown on the right side of FIG. The upper support roller 12 and the upper molding roller 11 are lowered to the positions indicated by reference numerals 12 ′ and 11 ′, and the pulley is rolled by the upper molding roller 11 ′ and the lower molding roller 13 to be rolled into the shape indicated by reference numeral 5. The upper forming roller 11 is provided with a stopper portion 15 so that the outer diameter of the flange portion 5a does not expand beyond the outer diameter design value. By the material that is excessively induced on the outer peripheral side of the flange portion 5a by rolling, The thick part 5c is formed. The thick portion 5 c is molded between the stopper portion 15 of the upper molding roller 11 and the outer peripheral end of the lower molding roller 13.
Thus, the intermediate shape pulley 4 (shown in FIG. 1D) before the rolling step B in FIG. 2 is formed into the shape of the pulley 5 in FIG. The thick portion 5c of the pulley 5 is formed into a thin cylindrical cylinder portion by post-processing such as flow forming.
Although not shown in FIG. 2, the lower positioning roller 19 approaches the mandrel 10 during the rolling process. As a result, the outer periphery of the shaft portion of the pulley 5 is processed into the shape of the lower positioning roller 19, and the inner periphery of the shaft portion of the pulley 5 is processed into the shape of the mandrel 10.

If the gap between the stopper portion 15 and the lower molding roller 13 is eliminated so that the thick portion 5c is not molded, a fixed pulley that does not require a cylinder portion can be molded. Further, if a space for the shaft to enter is provided at the axis of the upper support roller 12 or the mandrel 10, a fixed pulley integrated with the shaft can be manufactured by the same method as described above.
In this embodiment, a part of the flange portion in the circumferential direction (three locations in the first embodiment) is sandwiched between rolling tools (a pair of upper forming roller 11 and lower forming roller 13 in the first embodiment). The contact surface between the rolling tool and the flange portion is sequentially rotated. It is possible to roll the flange part to the outer diameter design value by locally applying a load with a rolling tool, and reduce the load capacity required for the equipment compared to the case of forging to the outer diameter design value. Can do. Moreover, the effect which prevents the flange part 4a at the time of rolling shaking from the axis | shaft is acquired by arrange | positioning a rolling tool at equal intervals in the circumferential direction of a flange part.

<Second Example>
Next, a second embodiment of the present invention will be described. In the second embodiment, the step (E) of expanding the outer diameter of the flange portion shown in FIG. 1 to the outer diameter design value L2 and the step (F) of forming the cylinder portion are simultaneously formed by a rolling step. . In this embodiment, (E) and (F) in FIG.

  FIG. 5 is a schematic cross-sectional view of an apparatus for carrying out the rolling process C according to an embodiment. The intermediate shape pulley 6 is set by being inserted into the upper end of the mandrel 20 as in the first embodiment. An upper molding roller 11 is disposed on the upper surface of the flange portion 6a, as in the first embodiment. An upper support roller 12 is disposed on the upper molding roller 11 but is not shown. Since the configuration of the device above the pulley 6 is the same as that of the device of FIG. 2 shown in the first embodiment, description thereof is omitted.

Instead of the lower forming roller 13, a pulley support die 17 is disposed on the back surface of the flange portion 6 a of the pulley 6. The pulley support die 17 has a cylindrical shape, and a cylinder portion forming surface 18 is formed on the outer peripheral side surface thereof. The cylinder part forming surface 18 extends in parallel with the rotational symmetry axis x of the flange part 6a (same as the rotation axis of the mandrel 20).
Further, the cylinder part forming roller 16 is disposed outside the cylinder part forming surface 18. The rotation axis of the cylinder part forming roller 16 is parallel to the rotational symmetry axis x of the flange part 6a. A space corresponding to the thickness of the cylinder portion in the pulley radial direction is secured between the cylinder portion forming surface 18 and the cylinder portion forming roller 16.

  FIG. 6 is a top view of an apparatus for performing the pulley manufacturing method according to the second embodiment. However, the upper support roller is omitted. In FIG. 5, for explaining the operation of the apparatus, the upper forming roller 11 and the cylinder portion forming roller 16 are drawn one by one on the same cross section, but actually, as shown in FIG. 6, the two upper forming rollers 11a and 11b are drawn. Are arranged symmetrically with respect to the rotational symmetry axis x of the pulley. Further, two cylinder part forming rollers 16a and 16b are arranged at positions rotated 90 degrees from the upper forming rollers 11a and 11b around the rotational symmetry axis x of the pulley (same as the rotation axis of the mandrel 20). This is to prevent the upper forming roller 11 and the cylinder portion forming roller 16 from interfering with each other. If the apparatus is rotationally symmetric when observed along the rotational symmetry axis x of the pulley, the pulley can be prevented from shaking during processing. The upper forming roller 11 and the cylinder part forming roller 16 may be three sets or four sets. In any case, it is preferable to arrange the rotation object when observed along the rotation object axis x of the pulley.

  The operations of the upper support roller (not shown) and the upper molding roller 11 in this apparatus are the same as those in the first embodiment. The flange portion 6a of the pulley is sandwiched between the upper molding roller 11 and the pulley support die 17, and the flange portion 6a is rolled to the outer diameter design value L2 by the load from the upper molding roller 11. In the second embodiment, the upper forming roller 11 and the pulley support die 17 correspond to one aspect of the rolling tool. Also in the second embodiment, pressure is applied to both the front and back surfaces of a part of the intermediate flange portion 6a in the circumferential direction, and the pressurization locations are sequentially moved in the circumferential direction. The flange portion 6a rolled in this way is prevented from having an outer diameter larger than the outer diameter design value L2 by the stopper portion 15 provided on the upper forming roller 11. And the flange part 6a which is going to spread outside by further rolling is guide | induced along the cylinder part molding surface 18 of the pulley support die 17 of the back side of the flange part 6a, and a thin cylindrical cylinder part is carried out by the cylinder part forming roller 16. 6b is molded. 5 and 6 show a state after the cylinder portion 6b is molded. That is, the pulley 6 shown in FIGS. 5 and 6 is the same as the pulley 6 shown in FIG.

Excess material that has been rolled by the upper forming roller 11 and the pulley support die 17 and guided to the outer periphery of the flange portion is formed by the cylinder portion forming roller 16 and the pulley support die 17 in part in the circumferential direction. Pressure can be applied from the outer peripheral side. As the mandrel 20 rotates, the flange portion 6a and the cylinder portion forming roller 16 relatively rotate around the rotational symmetry axis x of the flange portion 6a. The pressurization location by the cylinder part forming roller 16 and the pulley support die 17 sequentially moves in the circumferential direction of the flange part 6a, and as a result, the cylinder part 6b is formed.
In the second embodiment, the outer diameter of the flange portion is formed to the outer diameter design value L2 by the rolling process C, and the cylinder portion 6b is simultaneously formed. A cylinder part shape having a curved side surface can be formed by changing the shape of the cylinder part forming surface 18 of the pulley support die 17 and the cylinder part forming roller.

  Also in the second embodiment, in order to enlarge the flange portion 6a from the first enlarged diameter to the second enlarged diameter, it is not necessary to press the entire surface of the flange portion, and the upper forming roller 11 and the flange portion 6a are in contact with each other. Since it is sufficient to pressurize only the local range, the load necessary for molding can be reduced, and the cost of the manufacturing apparatus can be reduced.

  In both the first embodiment and the second embodiment, an intermediate shape pulley is manufactured in the forging process until the outer diameter of the flange portion is smaller than the outer diameter design value, and the remaining diameter from the outer diameter intermediate value to the outer diameter design value is manufactured. By processing the part in the rolling process described above, the processing time of the rolling process can be shortened, and the time manufacturing cost of the pulley can be reduced.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

It is a figure which shows the step change of the pulley shape in the manufacturing method of the pulley of an Example. It is a figure which illustrates typically a device which performs a rolling process of the 1st example. FIG. 3 is a cross-sectional view taken along line III in FIG. It is sectional drawing in the line shown by IV in FIG. It is a figure which illustrates typically the apparatus which implements the rolling process of the 2nd example. It is the figure which looked at the apparatus shown in FIG. 5 from the upper surface. It is a schematic diagram explaining the structure of a continuously variable transmission. It is a figure which shows the step change of the pulley shape in the conventional pulley manufacturing method. It is a figure which shows the step change of the pulley shape in the other conventional pulley manufacturing method.

Explanation of symbols

1: Material before pulley manufacture 2: Pulley shape in the middle of the forging process 3: Pulley shape in the middle of the forging process 4: Intermediate shape pulley 5: Pulley formed by the rolling process of the first embodiment 6: Second embodiment Pulleys 3a, 4a, 5a, 6a formed by the rolling process of: Flange portion 5c: Thick portion 6b: Cylinder portion 10, 20: Mandrel 11, 11 ': Upper forming roller 12, 12': Upper support roller 13: Lower forming roller 14: Lower support roller 15: Stopper portion 16: Cylinder portion forming roller 17: Pulley support die 18: Cylinder portion forming surface 19: Lower positioning roller 100: Continuously variable transmission L0: Material diameter L1: Outside the flange portion Diameter intermediate value (first enlarged diameter)
L2: Designed outer diameter of the flange (second enlarged diameter)

Claims (4)

In a method of manufacturing a pulley for a continuously variable transmission having a flange portion that is rotationally symmetric about a rotationally symmetric axis and that extends in the radial direction and the axial direction,
A first step of forging a small-diameter material using a forging die and forming an intermediate-shaped pulley having an intermediate-shaped flange portion having a first expanded diameter in which the material diameter is expanded;
A flange having a second enlarged diameter in which the first enlarged diameter is further expanded by applying pressure from both the front and back sides to a part in the circumferential direction of the intermediate-shaped flange portion and sequentially moving the pressurizing portion in the circumferential direction. A second step of forming a pulley having a portion;
The manufacturing method of the pulley for continuously variable transmission characterized by including.   In the second step, the rotary shafts of the pair of rollers are used as flange portions while holding the front and back surfaces of the intermediate-shaped flange portion with a pair of rollers each contacting the flange portion along the in-plane radiation of the flange portion. 2. The method according to claim 1, wherein relative rotation is performed around the rotational symmetry axis. In the second step, extra material is guided to the outer periphery of the flange portion,
Apply pressure from the inner and outer circumferences to a portion of the circumferential direction of the excess material guided to the outer circumference of the flange, and move the pressurization location sequentially in the circumferential direction. 2. The method according to claim 1, further comprising a step of forming a cylinder portion extending in the direction.   The back surface of the intermediate shape flange portion is supported by a die having an outer peripheral surface extending in the axial direction, and a flange portion forming roller that contacts the flange portion along the in-plane radiation of the flange portion is pressed against the surface of the intermediate shape flange portion. The cylinder part forming roller having a rotation axis substantially parallel to the rotational symmetry axis is pressed against the outer peripheral surface, and the rotation axis of the flange part forming roller and the rotation axis of the cylinder part forming roller are rotationally symmetric with respect to the flange part. 4. The manufacturing method according to claim 3, wherein relative rotation is performed around an axis.

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