JP3285508B2 - Manufacturing method of flat dies for thread rolling - 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 flat die used for manufacturing a screw. More specifically, the present invention relates to a method of manufacturing a flat die. The present invention relates to a method of manufacturing a flat die for manufacturing a special non-circular thread having a non-circular thread portion whose diameter is constant but the diameter of a crest gradually changes.

[0002]

2. Description of the Related Art To manufacture flat dies,
A thread of a seed roll, which is a prototype of a screw produced by grinding, is pressed against one surface of a substantially square pillar-shaped block material serving as a die material, and the surface of the block material is plastically deformed to form a thread groove.

[0003] A screw includes a normal circular screw such as a metric screw or a unified screw in which the diameters of the ridges and valleys of the screw are the same over the entire length, and other parts at a plurality of positions in one pitch of the screw. In the case where there is a non-circular screw having a polygonal cross-sectional projection shape with a larger crest diameter, and the screw thread is circular or non-circular over the entire length, a screw to be manufactured (hereinafter referred to as a product screw) Threads are formed in a flat die using a seed roll on which a thread having the same shape as that of the thread is formed.

By the way, a special non-circular screw 32 having a circular screw portion A, a non-circular screw portion B, and a tapered screw portion C formed following the head portion 30 and the non-screw portion 31, as shown in FIG.
In the circular screw portion A, as shown in FIG. 25, the diameters of the peaks 33 and the valleys 34 are constant, and the cross-sectional projection shape is a perfect circle.
27, the diameter 36 of the peak changes while the diameter of the valley 35 is constant, and the cross-sectional projected shape has a substantially regular hexagonal diameter. Further, as shown in FIG. The thread is formed so that the diameter of the peak 37 and the trough 38 becomes smaller toward the tip.

[0005] The non-circular screw portion B acts as a self-tapping screw for a raw hole or a burring hole when fastening the screw, and the circular screw portion A is formed on the inner periphery of the workpiece hole by the non-circular screw portion B. It has a feature that the tightening strength and the tightening torque can be increased by contacting the female screw with almost no gap.

[0006] The flat die for manufacturing the special non-circular screw 32 described above includes a thread groove for a circular screw portion having a constant depth and an angle, and a non-circular screw portion having a constant depth and an angle. Screw grooves must be formed on one rolled surface, but when flat dies are manufactured, if a seed roll having the same shape as the product screw is used, the average height of the thread of the seed roll will be a circular screw. And the non-circular threaded part are different.Therefore, there is a considerable difference between the amount of deformation of the block material due to the circular threaded part and the amount of deformation of the block material due to the non-circular threaded part, and the thread groove does not rise to a sufficient height. In addition, the heights of the ridges between the screw grooves were not aligned on the same plane, and the screw grooves could not be formed accurately.

Although it is possible to directly form a required thread groove in the block material by grinding, it is time-consuming and requires considerable skill to form an accurate thread groove.

[0008]

[Object] The object of the present invention is to provide a non-circular shape in which the diameter of the crest is gradually changed but the diameter of the crest is gradually changed on the tip side following the circular thread portion in which the crest and the crest of the thread are constant. An object of the present invention is to make it possible to accurately and easily produce a flat die for producing a special non-circular screw having a thread portion.

[0009]

In order to achieve the above object, a method of manufacturing a flat die for thread rolling according to the present invention comprises a method of manufacturing a flat die for forming a thread following a circular thread portion.
Special non-circular shape with non-circular thread and tapered thread
In the manufacturing method of flat dies for thread rolling to manufacture screws
There is a tapered portion at the tip
The diameter of all peaks and valleys except for the
It has a constant circular threaded part over the
Is a thread with a small diameter of both the peak and the valley toward the tip.
Prepare a rough screw type roll that has
Has a tapered part, from this base to the tip except the base
A continuous thread is formed at a constant pitch.
Is a circle in which the diameters of the peaks and valleys and the angles of the valleys are constant from the base side
The shape of the thread and the diameter of the peaks and valleys change gradually
Both the diameter of the circular thread and the diameter of the peaks and valleys decrease toward the tip.
Special roll with tapered thread
And a substantially square pillar-shaped block material groove
An inclined surface that is inclined upward and backward in the upper half of the surface to be formed
And a vertical surface extending above the inclined surface is formed.
The thread of the same roll is inclined with the vertical surface of the block material.
Forming a rough thread groove with a constant depth and valley angle
And the thread of the special type roll is aligned with the rough thread groove.
And roll it to the special thread
Groove with constant depth and valley angle, and special type roll
Ridges and ridges between grooves due to non-circular thread
Forming a wavy groove having a portion on the vertical surface of the block material
The depth and depth of the tape are
The angle of the valley is constant and the peaks and valleys follow the slope
Forming an inclined groove portion on the inclined surface of the block material,
The peak height of the peak in the groove
Align on a single plane and grind the bottom of the peak in the wavy groove
To increase the angle of the valley,
It is configured to form a thread groove for rolling . In addition,
The block material, which is the material of the flat die, is cut into a square by cutting.
Formed in a columnar shape and rolled the rough screw by the rough screw type roll
In, a rough screw type roll is sandwiched between two block materials.
And fix one block material and the other block material
Move the thread of the rough screw type roll to both block materials
Rolled into the thread groove by the special type roll
In between, a special type roll is sandwiched between two block materials ,
Fix one block and move the other block
Roll the thread of the special type roll into both block materials
You. Furthermore, the angle of the valley of the circular thread portion of the special type roll
60 °, for grinding the skirt of the peak in the wavy groove
Here, the angle of the valley is 80 to 90 °. In addition,
After the thread is rolled by a special type roll, the semi-finished flat die
Heat-treated to a hardness of HRC60-
62.

According to an embodiment of the present invention, a non-circular thread portion for pitch adjustment having the same shape as the non-circular thread portion is formed on the base side of the circular thread portion of the special kind roll.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a flat die for thread rolling according to the present invention. In the method of the present invention, a rough thread type roll 2
And two kinds of seed rolls, special seed roll 3, both of which are formed with threads of the same pitch on the outer periphery by grinding.

The thread portion 2a of the rough thread type roll 2 has a tapered tapered portion 2b at the tip, and all of the threads except for the tapered portion have a constant diameter of the crests and valleys over the entire length, and are circular threads. The diameter of the peak and the valley and the angle of the valley are formed in the same shape as the circular screw portion A of the product screw.
The peaks and valleys b are formed such that the diameters decrease toward the tip.

The special kind roll 3 is formed with a thread having a shape different from the thread of the product thread. As shown in FIG. 2, the outer peripheral surface of a round bar having a tapered portion at the tip is The screw portion 3a is formed up to the distal end except for the base portion 3b.

The thread of the thread 3a is continuous at a constant pitch from the base 3b side to the tip, and the thread 4 has a constant diameter of the crests and valleys of the thread, and each diameter of the crests and valleys. Have a tapered thread portion 7 in which the diameter of each of the peaks and valleys decreases toward the tip of the special seed roll 3.

The circular screw portion 4 corresponds to the circular screw portion A of the product screw. The cross-sectional projected shape is a perfect circle, the diameters of the crests 8 and the valleys 9 of the screw thread are both constant, and the angle of the valley is equal. θ _{1 is} also constant at, for example, 60 °.

The non-circular thread portion 5 has no portion corresponding to the product screw, and is a portion formed only for pitch adjustment at the time of rolling without being rolled into the block material 1. The shape of the thread is as follows. This is the same as the non-circular screw portion 6 to be described.

The non-circular thread portion 6 is formed between the circular thread portion 4 and the tapered thread portion 7 and corresponds to the non-circular thread portion B of the product screw. The highest parts 10a, 10a appear plural times per pitch, and the lowest parts 10b, 10b with the smallest peak diameter are formed between the highest parts 10a, 10a, for example, the highest parts appear six times per pitch. In this case, the cross-sectional projection shape of the non-circular screw portion 6 is a regular hexagon with rounded corners.

The uppermost portions 10a, 10a are formed at equal intervals, but are formed so as to be slightly shifted toward the leading end of the screw at every pitch of the screw, and are arranged in the axial direction of the special kind roll. The highest parts 10a and 10a appearing in FIG.
Appears twisted as shown by middle L ₁ and L ₂ , and has a twisted hexagonal column shape in appearance.

The peak height H ₂ and the valley angle θ ₂ of the highest portions 10a and 10a are determined by the above-described peak height H _{1 of} the circular screw portion 4.
And the valley angle θ ₁ , respectively,
0b, the height H ₃ of the mountain 10b is slightly smaller than the maximum height of the portion of the mountain H _2, also the angle theta ₃ valleys in the lowest portion becomes larger than the angle theta ₂ of the best part of the troughs ing.

The cross-sectional shape of the crest 10 of the non-circular thread 6 is the same as the cross-section of the crest of the non-circular thread B of the product screw, but the shape of the valley 11 is different from that of the product screw. Thus, in the non-circular thread portion B of the product screw, the diameter of the valley is constant and the cross section has a perfect circular shape.
In the non-circular thread portion 6, the diameter of the valley 11 is the same as the diameter of the crest 10, and the highest portion 11a, 11a and the lowest portion 11b, 11
b, and has a substantially regular hexagon substantially similar to the cross-sectional shape of the mountain.

The thread of the tapered thread portion 7 has the same shape as that of the tapered thread portion C of the product screw.
3 becomes smaller toward the tip of the special kind roll 3 at a constant rate, the height H _{4 of the} peak and the angle θ ₄ of the valley are constant,
The taper thread portion 7 of the special kind roll is formed longer than the taper thread portion C of the product thread. The rough screw type roll 2 and the special type roll 3 may have the same outer diameter and the same number of threads as the product screw. However, when the product screw has a small diameter, both the diameter and the number of the product screw are equal. May be used which is an integral multiple of.

Next, specific steps of manufacturing a flat die according to the method of the present invention will be described. <Creation of block material> Block material 1 which is the material of flat dies
Are formed by cutting. When the hardness of the block material 1 is HRC 15 or more, the hardness of the block material 1 is reduced by annealing so that the cutting work can be easily performed.

As shown in FIG. 10, the block member 1 is formed in a substantially quadrangular prism shape, and a vertical surface 1a is formed in the upper half portion of the surface on which the groove is formed, following an inclined surface 1b inclined upward and backward. The vertical width of this vertical surface 1a is a length corresponding to the total length of the circular screw portion 4 and the non-circular screw portion 6 of the special kind roll 3,
The width of the inclined surface 1b is longer than the length of the tapered thread portion 7 of the special kind roll 3, and the inclination angle is formed to be the same as that of the tapered thread portion 7.

<Rolling by Coarse Screw Type Roll> The block materials 1 and 1 are arranged so that the vertical surfaces 1a and 1a face each other, and the thread portion of the rough screw type roll 2 is sandwiched between these to fix one of the block materials. At the same time, the other block
The thread of the rough screw type roll 2 is rolled into both block materials 1 and 1 by reciprocating in the left and right direction as shown in FIG.
In addition, the surface of the inclined surface 1b is surface ground to slightly reduce the height of the crest between the screw grooves. By this rolling, a rough thread groove having a constant depth and a constant valley angle is formed in the block material.

<Rolling by special type roll> The thread of the special type roll 3 is fitted to the rough thread groove of the block materials 1 and 1 formed by the rough screw type roll 2, and as shown in FIG. The special kind roll 3 is sandwiched between 1. Similarly to the above-described rolling of a rough screw, one block material is fixed, and the other block material is moved in parallel in one direction to form a thread of the special kind roll 3 into the two block materials 1 and 1.

The block material 1 was reciprocated in the left-right direction when rolling with the rough screw type roll 2, but when rolling with the special type roll 3, the block material was moved only in one direction. Take care not to shift the positions of the highest and lowest parts of the non-circular thread. Once rolling with the special seed roll 3 is performed, remove the special seed roll from the block material once,
If necessary, the surface of the block material is ground by about 0.1 mm.

Then, the special kind roll 3 is set again between the block materials 1 and 1 by adjusting the pitch of the highest parts 10a and 10a in the non-circular thread portion 6 of the special kind roll 3. At this time, the non-circular screw portion 6 on the distal end side of the special kind roll 3 is surrounded by the blocks 1 and 1 and it is difficult to adjust the pitch. However, since the non-circular screw portion 5 is also formed on the base side, By marking the position of the highest part of the non-circular thread portion 5 on the block material, the pitch can be easily and accurately adjusted. Rolling by the special kind roll 3 is repeated until a thread groove is sufficiently formed in the block material 1 to obtain a semi-finished flat die 14.

As shown in FIG. 13, the semi-finished flat die 14 has a flat groove portion 15 formed by the circular thread portion 4, the non-circular thread portion 6, and the tapered thread portion 7 of the special kind roll 3, respectively.
It has a wavy groove 16 and an inclined groove 17. Flat groove 15
As shown in FIGS. 14 and 15, the depth H ₅ of the thread groove 18 and the angle θ _{5 of the} valley are formed to be constant over the entire length of the groove.

As shown in FIGS. 16 to 18, the wavy grooves 16 are formed on the ridges 19 and the valleys 20, respectively, at the valleys 11 and the peaks 1 of the ridges 10 in the non-circular screw portion 6 of the special kind roll 3.
The recesses 19a and 20a corresponding to the recesses 1a and 10a are formed.
Protrusions 19b and 20b corresponding to the lowest portions 1b and 10b of the peak 1 and the peak 10 are formed. The depth H ₆ of the groove in the concave portion and the angle θ ₆ of the valley are substantially the same as the depth H ₇ of the groove and the angle θ _{7 of the} valley in the raised portion, and the raised portion 19 b of the peak 19 is formed on the semi-finished flat die 14. It protrudes from the rolling surface 14a.

As shown in FIGS. 19 and 20, the inclined groove 17 has a constant depth H ₈ of the thread groove 21 and an angle θ _{8 of the} valley 22, and the ridge 22 and the valley 23 follow the inclined surface 1 b of the block material 1. It is inclined.

<Lead Angle Correction> It is checked whether or not the lead angle of the thread groove is formed to a required value by a helix angle gauge, and if correction is necessary, the upper surface of a flat die of a semi-finished product is ground. Lead angle.

<Cut Both Ends> Both ends of the semi-finished flat die 14 are cut and adjusted to a required length, and if necessary, the corners are ground and rounded.

<Heat treatment> The semi-finished flat die 14 is quenched at a required temperature and tempered to reduce the hardness of the block material to HR.
Increase to C60-62.

<Surface Grinding of Rolled Surface> The ridge 19b of the peak of the wavy groove 16 protruding from the rolled surface 14a is removed by surface grinding of the rolled surface. By this surface grinding, the peak 19 of the wavy groove 16 becomes flat as shown in FIG.
A deepest portion 24 having a depth of H _{6 and} a shallowest portion 25 having a depth of H ₉ are formed in the wavy groove 16.

As shown in <thread Grinding> 23, grinding the mountain skirt 26 at the shallowest part 25 of the undulating groove 16, occupies become large angle theta ₉ valley up to about 80-90 ° .

<Surface Grinding> Surfaces other than the rolled surface 14a of the semi-finished flat die 14 are ground and finished so that the surfaces are orthogonal to each other to obtain a finished flat die 27.

<Washing and Completion Inspection> After the block material was washed by homing in the liquid, the warp of the flat die 27 was measured, and the shape of the thread groove and the wavy groove 16 were measured with a tool microscope.
The pitch of the deepest part 24 at is measured.

The flat dies manufactured according to the above-described embodiment may be used as they are for manufacturing screws, but when mass-producing screws, the flat dies manufactured according to the above-described embodiment are used as master flat dies. A seed roll for mass production is manufactured using the master flat die, and a plurality of flat dies for mass production are manufactured using the seed roll for mass production.

[0039]

According to the method of the present invention, the following effects can be obtained by the above-described structure. The special kind roll used in the method of the present invention is such that the diameters of the ridges and valleys in the non-circular thread are gradually changed, and the average height of the ridges of the circular thread and the non-circular thread is almost the same. In addition, the amount of plastic deformation of the block material is substantially the same, and the thread groove can be formed accurately.

Further, since the rough thread groove is rolled by the rough thread roll before rolling the thread groove by the special kind roll, the deformation of the block material when the thread groove for the non-circular thread portion is rolled. And an accurate flat die can be manufactured.

Further, by forming a non-circular thread portion on the base side of the special type roll, it is easy to adjust the pitch in the non-circular thread portion when rolling by the special type roll, so that accurate rolling can be achieved. It can be carried out.

Therefore, according to the method of the present invention, a non-circular screw in which the diameter of the ridge is constant but the diameter of the ridge gradually changes is provided on the tip side following the circular thread portion in which the ridge and valley of the thread are constant. A flat die for manufacturing a special non-circular screw having a portion can be manufactured accurately and easily.

[Brief description of the drawings]

FIG. 1 is a front view of a rough thread type roll used in an embodiment of the method of the present invention.

FIG. 2 is a front view of a special kind roll used in the embodiment of the method of the present invention.

FIG. 3 is a horizontal sectional view of a circular thread portion of a special kind roll.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a horizontal sectional view of a non-circular thread portion of the special kind roll.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 5;

FIG. 8 is a horizontal sectional view of a tapered thread portion of a special kind roll.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is a perspective view showing a block material as a material of a flat die.

FIG. 11 is a plan view showing a rolling process using a rough screw type roll.

FIG. 12 is a plan view showing a rolling process using a special kind roll.

FIG. 13 is a front view showing a semi-finished flat die.

14 is a sectional view taken along line XIV-XIV of FIG.

FIG. 15 is a sectional view taken along line XV-XV in FIG. 14;

FIG. 16 is a sectional view taken along line XVI-XVI of FIG. 13;

FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 16;

18 is a sectional view taken along line XVIII-XVIII in FIG.

19 is a sectional view taken along line XIX-XIX in FIG.

20 is a sectional view taken along line XX-XX in FIG.

FIG. 21 is a front view showing a flat die of a finished product.

FIG. 22 is a sectional view taken along line XXII-XXII in FIG. 21;

FIG. 23 is a sectional view taken along line XXIII-XXIII of FIG. 22;

FIG. 24 is a front view of a product screw.

FIG. 25 is a horizontal sectional view of a circular screw portion of a product screw.

FIG. 26 is a horizontal sectional view of a non-circular thread portion of a product screw.

FIG. 27 is a horizontal sectional view of a tapered thread portion of a product screw.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Block material 1a Vertical surface 1b Inclined surface 2 Coarse screw type roll 2a Screw portion 2b Taper portion 3 Special type roll 3a Screw portion 3b Base 4 Circular screw portion 5, 6 Non-circular screw portion 7 Tapered screw portion 8 Crest of circular screw portion 9 Circular thread valley 10 Non-circular thread ridge 10a Maximum 10b Minimum 11 Non-circular thread valley 11a Maximum 11b Minimum 12 Tapered thread ridge 13 Tapered thread valley 14 Semi-finished flat die 14a Rolled surface 15 Flat groove 16 Wavy groove 17 Inclined groove 18 Screw groove 19 Wavy groove peak 19a Recess 19b Raised portion 20 Wavy groove valley 20a Depressed portion 20b Raised portion 21 Screw groove 22 Slope groove valley 24 Slant groove valley 24 Deepest part 25 Most shallow part 26 Hem of mountain 27 Flat die

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akihiro Uesugi No. 1-4-14, Fujimi-so, Kawana, Fujisawa-shi, Kanagawa Prefecture 56) References JP-A-7-178626 (JP, A) JP-A-50-97763 (JP, A) JP-A-6-190485 (JP, A) JP-A-4-171310 (JP, A) 44-16773 (JP, B1) JP 43-26743 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) B21H 7/00 B21H 3/06 B21H 3/12 B21D 37 / 20

Claims (7)

(57) [Claims] (A) A non-circular screw is provided at the tip end following the circular screw portion.
And special non- circular screws with tapered threads .
A method of manufacturing a order of flat dies for thread rolling, has a tapered portion tapered in (b) the distal end, the tapered portion
Except for all peaks and valleys except for
And a constant circular thread portion, and the tapered portion has a peak.
And the diameter of the valley have a thread that becomes smaller toward the tip.
That prepared rough screw type b Lumpur, also (c), has a tapered portion tapered at the tip, dividing the base
There are screw continuous at a constant pitch in the tip or from the base portion
Parts is formed, the threaded portion, each of the base side of the peaks and valleys diameter
Circular thread with constant angle of valley and valley
A non-circular threaded portion which changes gradually, respectively, each diameter of the peaks and valleys
Yes but the both Te supermarkets threaded portion serving as a small toward the tip
(D) The groove of the substantially rectangular block material, which is the material of the flat die , is prepared.
An inclined surface that is inclined upward and backward in the upper half of the surface to be formed
And (e) forming the thread of the rough thread type roll with the block material of the block material.
Rolled into vertical and inclined planes to maintain a constant depth and valley angle
Forming a rough thread groove, and (f) aligning the thread of the special type roll with the rough thread groove.
It was then rolling it, by screw strip of circular threads of special species role
And the flat groove depth and angle of the valley is certain, of special species roll
Non-circular thread ridges and ridges between valleys and grooves
Forming a wavy groove having a vertical groove on the vertical surface of the block material
The depth and depth of the tape are
The angle of the valley is constant and the peaks and valleys follow the slope
That the inclined oblique groove formed in the inclined surface of the block material, (g) mountain and surface grinding the ridges of the mountain in the wave groove
Height flush on a two assortment example of the angle of the valley by grinding the skirt surface of the mountain in (h) the undulating groove
The Ri by the tightening become large, non-circular threaded portion rolling for the screw
A method of manufacturing a flat die for thread rolling which forms a groove . (2) Cut the block material, which is the material of the flat die,
Forming into a substantially square pillar shape by machining The screw according to claim 1
Manufacturing method of flat dies for rolling. (3) For rolling of rough screw by the rough screw type roll
Then, insert a rough screw type roll between two block materials.
And fix one of the blocks and move the other block.
Move the thread of the rough screw type roll to both block materials.
The method for producing a flat die for thread rolling according to claim 1.
Law. (4) Angle of the valley of the circular thread of the special type roll
Of the flat die for thread rolling according to claim 1, wherein
Production method. (5) For rolling of thread groove by the special type roll
And a special type roll is sandwiched between two block materials,
Fix one block and move the other block
Roll the thread of the special type roll into both block materials
A method for manufacturing the flat die for thread rolling according to claim 1. 6. For grinding the skirt surface of the mountain in the wavy groove
And the angle of the valley is 80 to 90 °.
Manufacturing method of flat dies for thread rolling. 7. After thread rolling by the special type roll
In addition, heat treatment of semi-finished flat die
The thread rolling according to claim 1, wherein the hardness is HRC60 to 62.
Manufacturing method of flat dies for building.