JP2012187672A - Method of manufacturing rotor hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a rotor hub capable of reducing swarf and costs and improving work efficiency while maintaining high accuracy.SOLUTION: In this method of manufacturing a rotor hub including a cylindrical part having a cylindrical shape with a top and a flange with a disk mounting surface formed thereon, the method includes: a flow forming step of shaping a recess 51 to be an inner hole of the cylindrical part by pressing a mandrel 61 on an end face of a workpiece 50 while chucking the workpiece 50 to rotate it about an axial line O', shaping a protruding rib 52 to be the flange by moving a roller 62 along the axial direction while causing the roller 62 to abut against the outer peripheral surface of the workpiece 50 to cause an end of the workpiece 50 to protrude to the outer side in the radial direction, and shaping a peripheral wall surface 53 to be the outer peripheral surface of the cylindrical part; and a cutting step of forming the disk mounting surface by causing a blade tool 64 to abut against the surface of the protruding rib 52 while rotating the workpiece 50 in a chucked state about the axial line.

Description

  The present invention relates to a method for manufacturing a rotor hub.

  As a conventional method for manufacturing a rotor hub, for example, there is a manufacturing method as shown in Patent Document 1 below. More specifically, first, a work material is chucked and a work material is cut out from the work material. This work material is roughly processed into a shape close to the final shape, and as a schematic configuration, the workpiece has a cylindrical portion with a top, and projects from the opening edge of the cylindrical portion toward the outside in the radial direction. And a flange portion. Then, after the above-described work material cutting step, a primary finishing process is performed in which the outer peripheral surface of the cylindrical portion of the work material is chucked to cut and finish the outer peripheral surface and the lower surface of the flange portion and the inner hole of the cylindrical portion. Next, a secondary finishing process is performed in which the outer peripheral surface of the flange portion is chucked and the outer peripheral surface of the cylinder portion, the top wall upper surface, and the upper surface of the flange portion (disk placement surface) are cut and finished (for example, the following patent document) 1 [0020] and FIG. 13).

  Also, after the workpiece cutting process, the outer peripheral surface of the flange portion is first chucked to finish the outer peripheral surface of the cylindrical portion, the top surface of the top wall, and the upper surface of the flange portion, and then the outer peripheral surface of the cylindrical portion is chucked. There is also a method of finishing the outer peripheral surface and lower surface of the flange portion and the inner hole of the cylindrical portion (see, for example, paragraph [0021] of FIG. 14 and FIG. 14).

  Further, in the configuration in which the cylindrical portion is suspended from the lower surface of the top wall of the cylindrical portion, the outer peripheral surface of the cylindrical portion and the upper surface of the top wall are chucked by chucking the outer peripheral surface of the cylindrical portion instead of chucking the outer peripheral surface of the flange portion. There is also a method of finishing the upper surface of the flange portion. Thereby, distortion at the time of chucking can be suppressed (for example, refer to paragraph [0024] and FIG. 6 of Patent Document 1 below).

  Furthermore, there is also a method in which the top wall of the cylindrical portion is connected to the work material so that the work material is not separated from the work material during the work material cutting process. Thereby, it is possible to finish the outer peripheral surface and lower surface of a flange part, and the inner hole of a cylinder part, without chucking a workpiece | work material (for example, refer to the paragraph [0026] of the following patent document 1, and FIG. 7).

  There is also a method of forming a workpiece material by forging instead of cutting the workpiece material from the workpiece. That is, first, the work material is formed by forging, and then the outer peripheral surface of the cylindrical portion of the work material is chucked to finish the outer peripheral surface and lower surface of the flange portion and the inner hole of the cylindrical portion, and then the outer peripheral surface of the flange portion. To finish the upper surface of the flange portion, the outer peripheral surface of the cylindrical portion, and the upper surface of the top wall. Alternatively, after forming the workpiece material by forging, the outer peripheral surface of the flange portion of the workpiece material is chucked to finish the outer peripheral surface of the cylindrical portion, the top surface of the top wall, and the upper surface of the flange portion, and then the outer peripheral surface of the cylindrical portion is chucked. King to finish the outer peripheral surface and lower surface of the flange portion and the inner hole of the tube portion.

JP 2010-35367 A

However, in the conventional technique of cutting a workpiece material from a workpiece, there is a problem that a large amount of chips are generated during the workpiece cutting process, and there is also a problem that the material cost increases.
In addition, when the workpiece material is cut out from the workpiece by cutting, the forged streamline (metal flow) of the completed rotor hub extends straight along the axial direction, so it is discontinuous between the tube and the flange. Metal flow. For this reason, in order to obtain desired intensity | strength, it is necessary to thicken a flange part, and it becomes a cost increase.

  Moreover, in the conventional technique which shape | molds a workpiece | work material by forging, since it is necessary to chuck a workpiece | work material twice in order to perform a finishing process, there exists a problem that work man-hours are many and are complicated.

  The present invention takes the above-mentioned conventional problems into consideration, can reduce the amount of chips generated, and can reduce the cost by reducing the material cost and improving the strength and reducing the thickness. It is another object of the present invention to provide a method for manufacturing a rotor hub that can reduce the number of work steps and improve the work efficiency.

  The method of manufacturing a rotor hub according to the present invention includes a cylindrical portion having a top shape that can be fitted into a hole in the center of the disc, and projects radially outward from an opening edge of the cylindrical portion so that the disc can be placed thereon. In a method for manufacturing a rotor hub having a flange portion on which a disc mounting surface is formed, a mandrel is chucked on the work material on the one end surface in the axial direction while chucking the work material and rotating it around the axis. By pressing, a concave hole serving as an inner hole of the cylindrical portion is formed on the end surface on one side in the axial direction of the workpiece, and a rotatable roller is applied to the outer circumferential surface of the workpiece in the radial direction. By moving the roller relative to the workpiece along the axial direction of the workpiece while being in contact, the end on one axial side of the workpiece is protruded radially outward. Forming the convex ribs that form the flange A flow forming step of forming a peripheral wall surface that becomes an outer peripheral surface of the cylindrical portion, and a blade tool is brought into contact with the surface on the other axial side of the convex rib while rotating the workpiece around the axis while being chucked. And a cutting step of cutting the surface on the other axial side of the convex rib to form the disk mounting surface.

  Due to such characteristics, the rotor hub is roughly formed by the flow forming process to form a rough shape of the rotor hub, and then the disk mounting surface is formed by the cutting process. The flow forming process described above is a processing method in which a workpiece is plastically deformed to be molded into a predetermined shape, so that no chips are generated and the size of the workpiece is minimized. Further, in the rotor hub roughly formed by the flow forming process, the metal flow continues from the cylindrical portion to the flange portion, and therefore the strength of the connecting portion between the cylindrical portion and the flange portion is increased. Further, since the disk mounting surface is formed by cutting with high processing accuracy, a highly accurate disk mounting surface can be obtained. Furthermore, it is not necessary to rechuck from the flow forming process to the cutting process, and it is possible to carry out with one chuck.

Moreover, it is preferable that the manufacturing method of the rotor hub which concerns on this invention performs the said cutting process, inserting the said mandrel inside the said recessed hole.
Thereby, because the mandrel is inserted into the recessed hole, the rigidity of the end on the one side in the axial direction of the workpiece is increased, so that the workpiece (work) is less likely to be distorted when performing the cutting process, Cutting accuracy can be improved.

Further, in the method for manufacturing a rotor hub according to the present invention, in the cutting step, the blade portion is also brought into contact with at least one of the peripheral wall surface and the outer peripheral surface of the convex rib to perform cutting. It is preferable to finish the outer peripheral surface of at least one of the portion and the flange portion.
Thereby, the roundness of the rotor hub can be improved without increasing the work man-hours.

  According to the method for manufacturing a rotor hub according to the present invention, the rough forming of the rotor hub is performed in the flow forming process to form a rough shape of the rotor hub, and then the disk mounting surface is formed in the cutting process. The amount of chips generated can be reduced while ensuring the accuracy of the surface, and the material cost can be reduced. In addition, since the metal flow is continuous from the cylindrical portion to the flange portion, and the connecting portion between the cylindrical portion and the flange portion has high strength, the roller hub can be thinned, and the cost can be reduced. . Furthermore, since it can manufacture with one chuck | zipper, work man-hours can be reduced and work efficiency can be improved.

It is sectional drawing of the spindle motor provided with the rotor hub for demonstrating embodiment of this invention. It is sectional drawing showing the set state of the workpiece for demonstrating embodiment of this invention. It is sectional drawing showing the flow forming process for demonstrating embodiment of this invention. It is sectional drawing showing the cutting process for demonstrating embodiment of this invention.

  Embodiments of a method for manufacturing a rotor hub according to the present invention will be described below with reference to the drawings.

First, the configuration of the rotor hub 1 will be described.
A rotor hub 1 shown in FIG. 1 is a cup-shaped rotor that constitutes an outer rotor type spindle motor 100. As a schematic configuration thereof, a cylindrical portion 2 having a top shape and an opening edge portion 21 of the cylindrical portion 2 are provided. The flange part 3 protruded toward the radial direction outer side.
1 is a rotation center line of the rotor hub 1 and is hereinafter referred to as an “axis O”. A direction along the axis O is referred to as an “axial direction”, a direction orthogonal to the axis O is referred to as a “radial direction”, and a direction around the axis O is referred to as a “circumferential direction”. Furthermore, in the present embodiment, the top wall 20 side (upper side in FIG. 1) of the cylinder part 2 is “upper”, and the opening edge 21 side (upper side in FIG. 1) of the cylinder part 2 is “lower”. .

In addition to the rotor hub 1, the spindle motor 100 described above includes a base 10 on which a cylindrical rising cylindrical portion 11 is erected, a cylindrical sleeve 12 fitted inside the rising cylindrical portion 11, and an inside of the sleeve 12. A shaft 13 that is rotatably fitted to the shaft, a stator 14 that is disposed on the outer periphery of the rising cylindrical portion 11, and a permanent magnet 15 that is attached to the inner peripheral surface of the cylindrical portion 2 of the rotor hub 1. Yes. The shaft 13 is suspended from the central portion of the top wall portion 20 of the cylindrical portion 2 of the rotor hub 1 and is disposed coaxially with the rotor hub 1 with the axis O as a common axis. The rotor hub 1 is supported by the shaft 13 so as to be rotatable around the axis O.
The stator 14 has a configuration in which a coil is wound around a stator, and the plurality of stators 14 are arranged in parallel along the circumferential direction. And the above-mentioned permanent magnet 15 is arrange | positioned at the outer peripheral side of these several stators 14. As shown in FIG.

  Here, the configuration of the rotor hub 1 will be described in detail. The cylinder portion 2 is a disc fitting portion that can be fitted into the center hole D1 of the disc D. The cylindrical portion 2 has a configuration in which a cylindrical peripheral wall portion 22 is suspended from an outer edge of the top wall portion 20 that is substantially circular in plan view, and an opening edge portion 21 is formed at the lower end of the peripheral wall portion 22. The flange portion 3 is a disc placement portion on which the edge portion of the hole D1 of the disc D is placed, and is formed in an annular shape in plan view along the entire circumference of the opening edge portion 21 of the cylinder portion 2. . On the upper surface of the flange portion 3, a disk mounting surface 30 on which the edge of the hole D1 of the disk D is mounted is formed on the entire circumference.

  Next, a method for manufacturing the rotor hub 1 having the above-described configuration will be described.

First, as shown in FIG. 2, a round bar-like (columnar shape) workpiece 50 is prepared. The workpiece 50 is a metal material that is a material of the rotor hub 1 shown in FIG. 1 and is made of, for example, stainless steel. The diameter of the workpiece 50 is appropriately set according to the diameter of the cylindrical portion 2 of the rotor hub 1 shown in FIG. 1, and the workpiece 50 only needs to be long enough to be chucked.
2 indicates the central axis of the workpiece 50, and the central axis O ′ of the workpiece 50 and the axis O of the rotor hub 1 shown in FIG. 1 are on the same line. become. The direction along the central axis O ′ is referred to as “axial direction”, and the direction perpendicular to the central axis O ′ is referred to as “radial direction”.

  Then, the workpiece 50 described above is set on a lathe (not shown). More specifically, a lathe (not shown) includes a chuck 60, a flow forming mandrel 61 and a roller 62, and a cutting tool 64 (shown in FIG. 4). Then, the workpiece 50 is chucked by the chuck 60 described above, and the mandrel 61 is set on the end surface (tip surface) on one side (right side in FIG. 2) of the workpiece 50 in the axial direction. The roller 62 is set on the outer peripheral surface of 50.

  The chuck 60 is a gripping mechanism that grips the outer peripheral surface of the workpiece 50, and is configured to be rotatable around a central axis O ′ by a rotation mechanism (not shown). The workpiece 50 chucked by the chuck 60 is held in a state of protruding a predetermined length from the tip of the chuck 60, and the center axis O ′ is rotated by the chuck 60 being rotated by a rotation mechanism (not shown). Rotate around.

  The mandrel 61 is a metal core for forming the concave hole 51 shown in FIG. 3 on the distal end surface of the workpiece 50, and is a round bar member having a smaller diameter than the workpiece 50. The mandrel 61 extends on an extension line of the central axis O ′ of the workpiece 50 and is set in a state where the tip surface thereof is in contact with the tip surface of the workpiece 50. Further, the mandrel 61 is configured to be rotatable around the central axis O ′ by a rotation mechanism (not shown). The rotation direction of the mandrel 61 may be the same as or opposite to the rotation direction of the chuck 60 (workpiece 50). Further, the mandrel 61 is configured to be reciprocally movable in the axial direction by a moving mechanism (not shown).

  The roller 62 is a forming roller for forming the convex rib 52 shown in FIG. 3 at the front end portion of the workpiece 50 and forming the peripheral wall surface 53 of the workpiece 50 into a predetermined shape. It is attached freely. The roller 62 is disposed on the outer periphery of the workpiece 50 and is set in a state in which the outer peripheral surface thereof is in contact with the outer peripheral surface of the workpiece 50. The roller 62 is configured to be reciprocally moved along the axial direction by a moving mechanism (not shown). The roller 62 and the chuck 60 (workpiece 50) need only be configured to reciprocate relatively by a moving mechanism (not shown), and the chuck 60 (workpiece 50) moves without moving the roller 62. Alternatively, the roller 62 and the chuck 60 (workpiece 50) may be moved.

  Next, as shown in FIG. 3, a concave hole 51 is formed on the distal end surface of the workpiece 50, a convex rib 52 is molded on the distal end portion of the workpiece 50, and an outer peripheral surface of the workpiece 50 is formed. A flow forming step of forming the peripheral wall surface 53 having a predetermined shape is performed.

  More specifically, first, the workpiece 50 is rotated about the central axis O ′ by rotating the chuck 60 about the central axis O ′ by a rotation mechanism (not shown). Subsequently, in a state in which the workpiece 50 is rotated, the mandrel 61 is urged toward the workpiece 50 (the other side in the axial direction) by a moving mechanism (not shown), and the tip of the mandrel 61 is moved to the workpiece 50. Press against the tip. Thereby, the mandrel 61 is pushed into the workpiece 50 while the workpiece 50 is plastically deformed, and the concave hole 51 is formed in the distal end surface of the workpiece 50. The concave hole 51 is a hole that becomes an inner hole of the cylindrical portion 2 of the rotor hub 1, and is formed in a rough shape of the inner hole of the cylindrical portion 2.

  In addition, as described above, with the workpiece 50 being axially rotated, the roller 62 that rotates in contact with the outer peripheral surface of the workpiece 50 is rotated by a moving mechanism (not shown) along the axial direction (axial direction). Move toward one side. As a result, the outer peripheral surface of the workpiece 50 is plastically deformed so as to be scraped by the roller 62. As a result, the tip of the workpiece 50 protrudes radially outward over the entire circumference, and an annular annular convex rib 52 is formed at the tip of the workpiece 50, and the outer peripheral surface of the workpiece 50 A perfect circular peripheral wall surface 53 is formed. The convex rib 52 described above is a protruding portion that becomes the flange portion 3 of the rotor hub 1, and is formed in a rough shape of the flange portion 3. The peripheral wall surface 53 is a peripheral wall surface serving as an outer peripheral surface of the cylindrical portion 2 and is formed in a straight cylindrical shape along the axial direction.

Next, as shown in FIG. 4, a cutting process is performed in which the surface of the workpiece 50 subjected to the flow forming process is finished by cutting.
More specifically, the peripheral wall surface 53 described above in a state where the mandrel 61 is inserted into the concave hole 51 of the workpiece 50 while rotating the workpiece 50 around the central axis O ′ following the flow forming step. The cutting tool 64 is sequentially brought into contact with the surface on the other axial side of the convex rib 52 (left side in FIG. 4) and the outer peripheral surface of the convex rib 52. As a result, the peripheral wall surface 53 is cut to form the outer peripheral surface of the cylindrical portion 2, the surface on the other axial side of the convex rib 52 is cut to form the disk mounting surface 30 of the flange portion 3, and The outer peripheral surface of the annular convex rib 52 is cut to form the outer peripheral surface of the flange portion 3.
Note that a cutting tool may also be applied to the inner surface of the concave hole 51 to cut the inner surface of the concave hole 51 to finish the inner hole of the cylindrical portion 2.

  Next, the cutting process which cut | disconnects the to-be-processed material 50 in radial direction in the top surface position of the cylinder part 2 is performed. Thereby, the part (roller hub 1) to which the flow forming process and the cutting process described above are performed is separated, and the rotor hub 1 is completed.

  According to the method for manufacturing the rotor hub 1 described above, one rough forming of the rotor hub is performed in the flow forming process to form a rough shape of the rotor hub 1, and then the disk mounting surface 30 and the like are formed in the cutting process. The amount of chips generated can be reduced while ensuring the accuracy of the disk mounting surface 30, and the material cost can be reduced.

  Further, in the rotor hub 1 roughly formed by the flow forming process, the metal flow continues from the cylindrical portion 2 to the flange portion 3, so that the strength of the connecting portion between the cylindrical portion 2 and the flange portion 3 is increased. As a result, the roller hub 1 can be thinned, and the cost can be reduced.

  Further, it is not necessary to re-chuck from the flow forming process to the cutting process, and manufacturing can be performed with one chuck, so that the number of work steps can be reduced and the work efficiency can be improved.

  Further, since the cutting process is performed while the mandrel 61 is inserted inside the concave hole 51 formed by the flow forming process, the rigidity of the tip of the workpiece 50 during the cutting process is increased. Thereby, when performing a cutting process, the to-be-processed material 50 becomes difficult to be distorted, and it can improve cutting accuracy.

  Further, in the cutting process, not only the disk mounting surface 30 but also the outer peripheral surface of the cylindrical portion 2 and the outer peripheral surface of the flange portion 3 are finished, so that the roundness of the rotor hub 1 is improved without increasing the number of work steps. be able to.

As mentioned above, although embodiment of the manufacturing method of the rotor hub which concerns on this invention was described, this invention is not limited to above-described embodiment, In the range which does not deviate from the meaning, it can change suitably.
For example, in the above-described embodiment, the cutting process is performed while the mandrel 61 is inserted into the concave hole 51. However, in the present invention, the mandrel 61 may be pulled out from the concave hole 51 before the cutting process is performed.

  In the embodiment described above, the outer peripheral surface of the cylindrical portion 2 and the outer peripheral surface of the flange portion 3 are finished by cutting the peripheral wall surface 53 of the workpiece 50 and the outer peripheral surface of the convex rib 52 during the cutting process. However, in the present invention, when the desired roundness is ensured by the flow forming process, it is not necessary to finish the outer peripheral surface of the cylindrical portion 2 or the flange portion 3 by cutting.

In the embodiment described above, the rotor hub 1 used in the outer rotor type spindle motor 100 has been described. However, the present invention may be a rotor hub used in an inner rotor type spindle motor.
In the above-described embodiment, the cylindrical portion 2 is formed in a straight cylindrical shape. However, in the present invention, the cylindrical portion may be formed in a tapered cylindrical shape.
In the above-described embodiment, the convex rib 52 (flange portion 3) is continuously formed in an annular shape over the entire circumference, but the present invention is not limited to the annular convex rib or flange portion. . For example, a configuration may be employed in which a plurality of convex ribs (flange portions) are intermittently arranged in the circumferential direction along the opening edge of the cylindrical portion, or convex ribs formed in a C shape in plan view ( Flange portion).

  In addition, in the range which does not deviate from the main point of this invention, it is possible to replace suitably the component in above-mentioned embodiment with a well-known component, and you may combine the above-mentioned modification suitably.

DESCRIPTION OF SYMBOLS 1 Rotor hub 2 Cylinder part 3 Flange part 21 Opening edge part 30 Disk mounting surface 50 Work material 51 Concave hole 52 Convex rib 53 Peripheral wall surface 61 Mandrel 62 Roller 64 Cutting tool

Claims (3)

A cylindrical portion with a top shape that can be fitted into a hole in the center of the disc, and a flange that protrudes radially outward from the opening edge of the cylindrical portion and has a disc placement surface on which the disc can be placed A rotor hub having a portion,
While chucking the workpiece and rotating it around the axis, the mandrel is pressed against the end surface on one side in the axial direction of the workpiece, so that the end of the cylindrical portion on the end surface on the one side in the axial direction of the workpiece A concave hole serving as an inner hole is formed, and a rotatable roller is brought into contact with the outer peripheral surface of the workpiece in the radial direction, and the roller is moved relative to the workpiece. By moving along the axial direction, the end on one side in the axial direction of the workpiece is protruded radially outward to form a convex rib that becomes the flange portion, and the circumference that becomes the outer peripheral surface of the cylindrical portion A flow forming process for forming a wall surface;
While rotating the work piece around the axis while being chucked, the surface of the convex rib on the other side in the axial direction is cut by bringing the cutting tool into contact with the surface on the other side in the axial direction of the convex rib. A cutting process for forming a disk mounting surface;
A method of manufacturing a rotor hub, comprising: In the manufacturing method of the rotor hub according to claim 1,
The method of manufacturing a rotor hub, wherein the cutting step is performed while the mandrel is inserted inside the concave hole. In the manufacturing method of the rotor hub according to claim 1 or 2,
In the cutting step, the outer periphery of at least one of the cylindrical portion and the flange portion is cut by bringing the blade portion into contact with at least one of the peripheral wall surface and the outer peripheral surface of the convex rib. A method of manufacturing a rotor hub, wherein a surface is finished.

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