JP3530815B2 - Manufacturing method of small diameter shaft-shaped member - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a small-diameter shaft-shaped member suitable for manufacturing a small shaft-shaped member such as a wristwatch stem.

[0002]

2. Description of the Related Art Due to recent advances in precision machining technology,
Precise manufacturing of extremely small parts has become possible. Especially, small-diameter shaft-shaped members that support rotating members in small machines include, for example, shaft members such as wristwatch stems that have been widely used in the past, and in recent years hard disks for personal computers. It has come to be used in a wide range of fields such as movable parts.

The wristwatch stem, which is a typical example of the shaft-shaped member as described above, has a structure as shown in FIG. 4, for example. That is, the winding stem 30 shown in FIG.
In Fig. 1, a screw 31 for screwing in a crown that is rotated by a finger when adjusting the time is provided on the left side in the figure, and a shaft support portion 32 having a small diameter is provided on the right end. As shown in FIG. 2B, the shaft support 32 is provided with a spiral wheel fitting portion 33 having a substantially rectangular cross section, a correction transmission wheel shaft portion 34, a protrusion 35, a mandrel engagement groove portion 36, and the screw 31. It is formed of a shaft core portion 37 and the like.

There are various modes of such a winding stem depending on the type of the timepiece, and for example, a winding stem 38 having a shape as shown in FIG. 4 (c), a correction transmission wheel shaft portion 34, or a protruding portion. 35 and various types such as one in which the mandrel engaging portion 35 has a different shape. However, as a basic configuration, a columnar shaft support portion 32 at the tip, a prismatic ratchet wheel fitting portion 33 having a polygonal cross section for fitting a crown wheel that rotates a minute hand and an hour hand, and a screw for mounting a crown. 31 is provided as an essential component.

In the manufacture of a winding stem as a member consisting of a columnar portion and a prismatic portion as described above, a metal rod was previously machined to form a groove or a portion having a different diameter. In order to process the prismatic portion, the manufacturing process was performed by cutting such as planing.

In such a technique, two cutting processes, that is, a cutting process and a planing process, are required, and it takes a long time to process and the utilization ratio of raw materials is low, so that it is difficult to mass-produce parts and reduce manufacturing cost. There was a problem that was. To solve this, for example, Japanese Unexamined Patent Publication No. 8-68866.
As described in the publication, there is proposed a technique of forming a schematic shape of a winding stem by forging, and then subjecting this to a rolling process centered on an axis to obtain an accurate shape.

[0007]

According to the technique described in the above publication, since the cutting process is not performed, the mass productivity of parts is improved and the manufacturing cost is lower than that of the previous technique. Is expected to become. However, in this technique, the first forging step for forming the schematic shape of the winding stem is as shown in FIG. 7, in which a wire having a predetermined diameter as shown in FIG. Then, the tapered portion B is formed at one end of the shaft-shaped body A by the first die as shown in (b), and then the tapered surface C is formed by the second die as shown in (c). The small diameter portion D is formed.
Further, the tapered surface C and the small diameter portion D are further processed by the third die to form the small diameter portion E and the prismatic portion F as shown in (d). The fourth mold forms a flat diameter portion G, a trapezoidal portion H, and a shaft core portion I as shown in (e).

Since such a forging process is carried out by a series of operations, it can be processed in a short time to some extent, but in order to take out the finally obtained member from the forging die, for example, as shown in FIG. As shown in, it is necessary to insert a smaller diameter extrusion pin P from the end hole L of the die K forming the smallest diameter portion E and push the end of the smaller diameter portion E to take it out of the die K.

Although the strength of the extrusion pin P used at this time is selected to be sufficiently strong, the small diameter portion E and the inner surface of the mold have a very large friction resistance during the forging process, and the small diameter portion is For example, since the diameter is as small as about 0.5 mm, it is difficult to push it out by the push pin, and there is a problem that the pin buckles if it is pressed strongly against it.

Therefore, with this method, it is not always possible to obtain the expected effects of improving mass productivity and reducing manufacturing costs. Further, since the above problem becomes more remarkable as the diameter of the shaft-shaped component becomes smaller, the development of other means has been desired for the future manufacture of a smaller shaft-shaped member.

Therefore, according to the present invention, a small-diameter shaft member, which has a cylindrical portion and a prismatic portion on the same axis, can be manufactured accurately, in a short time, reliably, and inexpensively with a simple device. An object of the present invention is to provide a method for manufacturing a strip-shaped member.

[0012]

In order to solve the above problems, the present invention relates to a method for manufacturing a small-diameter shaft-shaped member having a cylindrical portion and a prismatic portion on the same axis. Stage of final product of shaft-shaped member by aging
Shaped part that connects smoothly by reducing the stepped part in the difference part
And a rotary swaging step of forming a schematic shape of the shaft-shaped member, and then performing a rolling process centered on the axis of the shaft-shaped member to form the shaft-shaped component in a more accurate shape. And a step of producing a shaft-shaped member, which is a method for manufacturing a small-diameter shaft-shaped member.

According to a second aspect of the present invention, in the rotary swaging step, at least the prismatic portion of the shaft-shaped component is processed, and in the rolling step, at least the columnar portion including the threaded portion is processed. The method for manufacturing a small-diameter shaft-shaped member according to claim 1 is characterized by the above .

The invention according to claim 3 is characterized in that the shaft member is a wristwatch winding stem.
The manufacturing method of the small-diameter shaft-shaped member is.

[0015]

Embodiments of the present invention will be described with reference to the drawings. The present invention is most characterized in that a rotary swaging process is applied instead of the forging step as the first step in the conventional technique described in the above publication, whereby the small-diameter shaft-shaped member can be forged. This is to solve the above-mentioned problems in molding.

Rotary swaging is a well-known technique. For example, as shown in FIG. 5A, a material 42 as a material to be machined located at the center is radially arranged around the material 42. In the figure, the four dies 43 move in the axial direction to press the material 42 from the surroundings so that the material 42 is finally pressed into a shape formed by the inner surface of the die 43. is there.

As shown in FIG. 5B, the die 43 is slidably arranged in a spindle 46, and similarly, a backer 44 is slidable in the spindle 46 so as to face the back surface of each die 43. It is located in. A cam surface 48 is formed at the end of the backer 44, and the cam surface 48 and the outer peripheral surface of the backer 44 form a roller raceway surface on which the roller 45 rolls as a whole.

In the system in which the spindle is stopped by such a device, each die 43 hits the material 42 from the same direction via the backer 44 by the rotation of the roller without rotating the material 42 as the workpiece. Then, pressure is applied to mold into a predetermined shape. By this method, it is possible to form a modified cross section other than a circular shape.

Further, as shown in FIG. 6, for example, a wedge member 49 which is movable in the axial direction of the material 42 is arranged between the die 43 and the backer 44 in the apparatus having the above-mentioned structure, and the wedge member 49. By changing the die interval by taking in and out, it is possible to perform a process of narrowing the intermediate portion of the material.

In such rotary swaging, the deformation is performed under the radial compressive stress and the axial tension is not normally applied, so that the hydrostatic stress component during machining is high, and the additional shear strain is added. Also few. Therefore, cracking during processing is less likely to occur as compared with other methods, and it is also suitable for forging processing of a material having relatively poor ductility. As a typical example of the difficult-to-process material, hot forging processing of molybdenum, tungsten, etc. has been put into practical use, and can be sufficiently used for the wristwatch stem as described above.

The present invention uses the rotary swaging process as described above to manufacture a shaft-shaped member such as a wristwatch winding stem. In manufacturing a winding stem having a shape as shown in FIG. , For example, a rotary swaging machine 1 using an inner surface die as shown in FIG. 1 in the first step
Is used to process. The processing into such a shape can be performed by adopting the same mechanism as the above-mentioned conventional technique.

This rotary swaging machine 1 is shown in FIG.
As shown in (b), the first die 5, the second die 6, the third die
The processed portion of the material 2 is formed on the inner peripheral surface of the four dies including the die 7 and the fourth die 8. This is because a part of the winding stem manufactured in this embodiment is provided with the prismatic portion 3 having a quadrangular cross section, and the operation of hitting the center material 2 with four dies from the outer circumference toward the center. By doing
It is molded into the inner shape of the die. In this forming process, the die may be rotated 90 degrees away from the center, and then the same operation may be performed to evenly swage the material.

As described above, in the rotary swaging process, since the metal material of the processed member is hit from the periphery, it is difficult to form the step portions having different diameters at right angles to the metal material. By forming an extra portion 4 shown by fine hunting in FIG. 1,
Mold it into a shape that reduces the step difference and connects smoothly. That is, the inner surface shape of the rotary swaging machine is formed in such a shape that this portion remains in excess of the shape of the final molded product.

The winding stem formed by the rotary swaging process into such a shape is different from the one formed by forging in the above-mentioned conventional example, and easily manufactures a precise part without using an extruding pin or the like that easily buckles. can do. FIG. 2A shows a material 2 molded by the rotary swaging machine, and in this material 2, at least the prism portion 11 has the shape of the final molded product. In the example shown in FIG. 1, a large-diameter collar 9 is provided at the end of the material 2 to guide the subsequent rolling process, and this part is cut off after the rolling process is completed. .

A material 2 molded by this rotary swaging machine is, for example, as shown in FIGS. 2 (b) and 2 (c),
Finally, in order to mold the outer shape of the winding stem 30 of the final molded product as shown in FIGS.
It is arranged so as to be sandwiched by the rolling machine 15 composed of eight, and pressure is applied from the vertical direction in the figure to repeatedly move in the plane direction to perform the rolling process. At this time, the collar 9 at the end of the material 2 serves as a guide, and the screw die 2 formed on the upper die 17 and the lower die 18
With 0, a screw is roll-formed on the shaft core 10 of the winding stem. However, in the die of the rolling machine 15, as shown in FIG. 1A, the relief portion 19 is formed so that at least the prism portion 11 does not perform the rolling action. The front and rear parts of the rolling machine 15 are formed into a predetermined shape by the rotary swaging process described above, so that in the rolling machine 15, each relief part 19 is formed to form a part which does not need to be rolled. Shows. In addition, as shown in FIG. 3, since the dimensional accuracy of the front and rear portions of the prismatic portion 11 is also adjusted, it may be a portion that performs a rolling action.

In such a rolling process, for example, the extra portion of the final engaging product formed by the rotary swaging process such as the posterior engaging portion 12 is formed by the narrowing portion 16 formed in the die of the rolling machine. The shape of the final molded product is obtained by rolling and shaping the threaded portion and correcting the dimensions during rotary swaging. The brim formed on the end of the material as described above is then cut off.

By the molding process as described above, FIG. 4 (a)
Various winding stems as shown in (b) or (c) can be manufactured. Further, not limited to the above-described winding stem, a small-diameter shaft-shaped member provided with a columnar portion and a prismatic portion having the same shape as the winding stem on the same axis line is used as a rotary member constituting a schematic shape of the shaft-shaped member. It can be manufactured by a swaging step and a subsequent rolling process centered on the axis of the shaft-shaped member. At this time, in the rotary swaging step, at least the prismatic portion is processed, and in the rolling step, at least the cylindrical portion is processed. In addition, in the prismatic portion described above, all the corner portions are simply projected,
Not limited to polygonal prisms whose angle is less than 180 degrees, but a part of the corner is recessed, such as a member with a small gear directly protruding from the shaft, such as a clock pin. The present invention can be similarly applied to the molding of a member having a prismatic portion such as a polygon having a portion having a corner angle of 180 degrees or more, which is present inside the portion.

[0028]

The invention according to claim 1 of the present invention is a method of manufacturing a small-diameter shaft-shaped member having a columnar portion and a prismatic portion on the same axis, and a schematic shape of the shaft-shaped member is formed by rotary swaging. Rotary swaging process to
Then, a shaft-shaped member is manufactured by a rolling process in which the shaft-shaped member is subjected to a rolling process to form the shaft-shaped component in a more accurate shape. Since it is the manufacturing method described above, it is possible to overcome the difficulty of manufacturing due to the buckling of the extrusion pin, etc. in the forging process that is the conventional first process, and to easily manufacture the small-diameter shaft-shaped member. It can be manufactured reliably in a short time and at low cost.

Further, in the invention according to claim 2, in the rotary swaging step, processing of at least the prismatic portion of the shaft-shaped component is completed, and in the rolling step, at least the cylindrical portion including the screw portion is processed. In the method for manufacturing a small-diameter shaft-shaped member characterized in that it is not necessary to form the prismatic part of the shaft-shaped component by machining such as planing following the rolling process, and easily and reliably. The prismatic portion can be molded.

In the invention according to claim 3, the shaft-shaped member is a wristwatch winding stem. In the method for manufacturing a small-diameter shaft-shaped member, a typical small-diameter shaft-shaped member is provided. It is possible to easily and inexpensively manufacture the winding wrist stem of the wrist watch.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a die portion of a rotary swaging machine used for rotary swaging as a first manufacturing step in an example in which the present invention is used for manufacturing a wristwatch stem; Is an axial sectional view,
(B) is sectional drawing of the AA part of (a).

FIG. 2 is an example of a rolling process as a second manufacturing process in the same embodiment, and (a) is a plan view of a material formed by rotary swaging before the rolling process is applied. , (B) is a sectional view of the rolling machine, and (c) is a plan view of a die on one side of the rolling machine.

FIG. 3 is another example of the rolling process, FIG. 3A is a sectional view of the rolling machine, and FIG. 3B is a plan view of a die on one side of the rolling machine.

FIG. 4 is an example of a winding stem of the wristwatch manufactured in the same embodiment, (a) is a plan view of the first example, and (b) is its B-.
It is a B partial sectional view, (c) is a top view of a 2nd example.

FIG. 5 is an example of a rotary swaging machine, (a)
Is a sectional view thereof, and (b) is a partially enlarged view of (a).

FIG. 6 is a sectional view showing another example of a rotary swaging machine.

FIG. 7 is a diagram showing a forging process in a manufacturing process of a winding stem of a wristwatch that has been conventionally proposed.

FIG. 8 is a diagram showing a step of extruding a material after forging from a forging machine in the conventional forging step described above.

[Explanation of symbols]

1 Rotary swaging machine 2 material 3 prismatic part 5 First Dice 6 Second Dice 7 Third Dice 8 Fourth Dice 9 collar part 10 Shaft core 11 Prism 12 Oshidori engagement part 13 bulge 15 Rolling machine 16 Narrowing part 17 Upper mold 18 Lower mold 19 Runaway 20 screw type

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI // B21H 3/02 B21H 3/02 (58) Fields investigated (Int.Cl. ⁷ , DB name) B21J 1/00-13 / 14 B21J 17/00-19/04 B21K 1/00-31/00 B21H 3/02 B21H 3/06 B21H 3/12

Claims (3)

(57) [Claims] 1. A method of manufacturing a small-diameter shaft-shaped member having a columnar portion and a prismatic portion on the same axis, wherein the stepped portion is reduced in the stepped portion of the final product of the shaft-shaped member by rotary swaging.
Eliminate the rough shape with a shape part that connects smoothly without
A rotary swaging process that form, then, to produce the shaft-like member by the rolling process is subjected to rolling around the axis of the shaft-like member to form the shaft-like component to a more accurate shape A method for manufacturing a small-diameter shaft-shaped member, comprising: 2. Completing at least the processing of the prismatic portion of the shaft-shaped component in the rotary swaging step,
The method for manufacturing a small-diameter shaft-shaped member according to claim 1, wherein at least the columnar portion including the threaded portion is processed in the rolling step. 3. The method for manufacturing a small diameter shaft-shaped member according to claim 1, wherein the shaft-shaped member is a wristwatch winding stem.