JPH01107937A - Manufacture of spiral formed body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a threaded body having threads such as trapezoidal threads and square threads formed thereon.

[Prior art]

BACKGROUND ART A threaded body having a trapezoidal thread or a square thread is widely used as a feed screw shaft material of a feed mechanism of a machining device such as a lathe or a variety of lifting devices. The feed screw shaft material has a variety of lengths, ranging from short to long, but generally has a length of 2 to 5 m. Moreover, the shape of the thread has a considerably larger pitch, groove depth, etc. than that of a thread forming body in which a triangular thread is formed.

When forming such a trapezoidal thread or square thread, unlike when forming a triangular thread whose groove depth is relatively small relative to the shaft diameter and can be cold rolled, the groove depth of the thread is smaller than the shaft diameter. Since the diameter is larger than that, the amount of processing becomes large, making cold rolling practically impossible.

Therefore, the trapezoidal thread or the square thread is generally formed by cutting.

[Problem that the invention seeks to solve]

When forming the trapezoidal thread or square thread by cutting,
Since the amount of cutting is large and there is a limit to the machining speed, there is a problem that the machining time becomes long and the machining cost increases. Further, in the case where the thread forming body on which the trapezoidal thread or square thread is formed is long, when processing the trapezoidal thread or square thread, the workpiece is bent by the pressing force of the cutting tool. There is a problem that machining accuracy decreases, and there is also a problem that machining speed needs to be sufficiently slowed because cutting heat is likely to be generated. In addition, in order to suppress the occurrence of deflection, which is a problem when machining trapezoidal or square threads of the long threaded body, the hardness of the workpiece is increased (for example, if the workpiece is carbon steel) , the workpiece is subjected to quenching and tempering to increase its hardness), and as the hardness increases, the cutting resistance increases, resulting in a further increase in processing costs.

The present invention has been made in view of the above circumstances, and is intended to manufacture a thread forming body that forms threads such as trapezoidal threads and square threads by plastic working instead of cutting processing which has various problems as described above. The purpose of the present invention is to provide a method for improving manufacturing efficiency and reducing manufacturing costs.

[Means for solving problems]

The method for producing a thread forming body according to the present invention includes arranging three or four rolling rolls around a pass line, each of which has a plurality of annular grooves formed in the circumferential direction on the outer peripheral surface for rough forming the thread. By using an inclined rolling mill, the metal material is hot fed between the rolling rolls, thereby performing inclined rolling on the metal material, and rough forming threads on the outer peripheral surface of the metal material. A first thread forming body is obtained, the metal oxide on the surface of the first thread forming body is removed to obtain a second thread forming body, and then a disk portion for finishing the thread. By using an inclined rolling mill having three or four rolling rolls arranged around the pass line, and feeding the second thread forming body between the rolling rolls in a cold state, the second thread forming body is It is characterized in that the strip forming body is subjected to inclined rolling to finish the threads on its outer peripheral surface.

[Function] In the case of the method of the present invention, the metal material is hot inclined-rolled to rough form the threads, so that the threads of trapezoidal threads, square threads, etc., which conventionally had to be cut, can be formed. can be realized by plastic working. Furthermore, the roughly formed threaded threads can be subjected to cold tilt rolling, which allows for highly accurate finishing, by removing the metal oxides on their surfaces. Therefore, by subjecting the thread to cold tilt rolling, a thread with high dimensional accuracy is formed, and the surface roughness of the thread is equal to or better than that of a machined surface.

〔Example〕

The present invention will be described in detail below based on drawings showing an embodiment of the present invention in the case where the number of rolls is three.

Fig. 2 is a front view showing the main parts of the apparatus used for carrying out the method of the present invention, particularly the hot tilt rolling process (the grooves of the rolling rolls are omitted), and Fig. 3 is the same as that shown in Fig. 2. It is a side view showing an enlarged cross section of the rolled part along the m-m line, and 4 in the figure indicates a solid metal material having a circular cross section, and the metal material 4
is transferred in the axial direction and inclined-rolled by a set of three cone-shaped rolling rolls 1.2.3 of a cross-type inclined rolling mill installed at the rolling position of the pass line, and threads are formed on the outer peripheral surface. The first thread forming body 41 is formed by rough forming.

The rolling rolls 1.2.3 each have the same surface angle α (see Fig. 3), and their axes are inclined so that the shaft ends on the same side face toward the same side in the circumferential direction (this axis The angle β of the line with respect to the pass line is called the inclination angle), and the shaft end on the same side is inclined so that it approaches or moves away from the pass line (the angle T of this axis line with respect to the pass line is called the intersection angle). good,
The cross angle T in the direction in which the roll axis separates from the pass line on the exit side is defined as positive.

The metal material 4 is threaded at a portion where the distance between the outer peripheral surface of the rolling rolls 1, 2.3 and the pass line is smaller than the radius of the outer periphery of the metal material 4 passing therethrough, that is, the outer periphery of the rolled portion. For rough forming, a plurality of annular grooves, for example 5 to 7 annular grooves, each having a trapezoidal cross section wider on the opening side, are cut in the circumferential direction at appropriate length intervals in the axial direction. The positions, intervals, widths, and depths of the grooves are different among the rolls, as partially shown in FIG. 3, and the intervals among the rolls are also different in the axial direction.

The position and spacing of the grooves are then determined depending on the height and spacing of the threads to be formed. Also, the α, β, γ, etc. of the inclined rolling rolls related to these are determined. The position of the grooves differs among the rolling rolls, and for each rolling roll, the intervals are gradually adjusted according to the amount of stretching from the material input side to the material exit side. The threads are guided into the grooves of the next roll and are formed one after another.The width and depth of the grooves are the same between the rolling rolls.
Further, for each rolling roll, changes are made as necessary (for example, changes such as small on the material input side and large on the material exit side).

In addition, the inclination angle of each groove with respect to the roll axis in the depth direction is such that when the thread to be formed is perpendicular to the screw axis, the upright direction of the groove is set at the above-mentioned intersecting angle in the material exit direction. The slope is formed at the same angle as T.

FIG. 4 is a front view showing the main parts of the apparatus used for implementing the method of the present invention, particularly for implementing the cold tilt rolling process (the grooves of the rolling rolls are omitted), and FIG. 5 is the same as that shown in FIG. 4. It is a cross-sectional view taken along the line V-V, and 42 in the figure indicates a second thread-forming body obtained by removing the metal oxide on the surface of the first thread-forming body 41 obtained by the above-mentioned apparatus, and The strip forming body 42 is transferred in the axial direction, and a set of three cone-shaped roll rolls 11.2 of a cross-type inclined rolling mill are provided at the rolling position of the pass line.
1.31, and the threads on the outer peripheral surface are finished.

The cross-type inclined rolling mill provided with the rolls 11, 21, 31 has the same structure as the rolling mill with the rolls 1, 2.3. Further, the rolling roll 11.2
1.31 is a rolling roll having two types of disk parts, a groove forming disk part A and a top forming disk part B, both in separate parts, and the groove forming disk part A
While finishing (sizing) the groove between adjacent threads of the second thread forming body 42, the top part of the thread is finished by using the top forming disk part B. There is. In addition, when three rolling rolls 11, 21, and 31 are used as in this embodiment, the phases of adjacent rolls are shifted by 120'', so that finishing processing can be performed effectively on each disk portion A and B. ing.

When carrying out the method of the present invention using such an apparatus, first,
A metal material 4 having a circular cross section as shown in FIG.
000°C).

Next, the metal material 4 heated to a predetermined temperature is shown in FIG.
As shown in FIG. 6(a), the material is fed between the rolling rolls 1, 2, and 3, and subjected to inclined rolling by the rolling rolls 1, 2.3, so that threads are formed on the outer peripheral surface of the rolling roll.

It is roughly formed as shown in (b), (c), and (d) to form the first thread formed body 41. Note that the arrow in FIG. 6 indicates the direction of the load applied to the metal material 4. That is, when rolling of the metal material 4 is started, the metal material 4 is rolled by the rolling roll 1. 2.
3, and then rolled by them at three locations in the circumferential direction, and progresses while rotating around the axis. Therefore, subsequent rolling is performed in a spiral manner, and the rolled metal material 4 advances toward the roll exit side where the distance between the pass line and the rolls 1.2.3 is narrow. and three rolls 1,2゜3
As a result of the sequential rolling, the inside of the rolled portion is elongated in the axial direction, thereby widening the thread spacing. If the roll settings are made so that the grooves that contribute to the next rolling are aligned with the widened threaded threads, the screw threads, such as trapezoidal threads with a high height and long pitch, can be rolled without crushing the threads. can be molded.

The first thread formed body 41 thus obtained is shown in FIG.
As shown in FIG. 2, the metal oxide on the surface is removed by pickling treatment to form the second thread forming body 42.

Furthermore, as shown in FIG. 1(d), the second thread forming body 42 is cold fed between the rolling rolls 11 and 21.31, and subjected to inclined rolling by the rolling rolls 11 and 2L31. The threads on the outer circumferential surface are then finished. That is,
The grooves between adjacent threads are finished by the groove-forming disk portion A of the roll 11.21.31, and the tops of the threads are finished by the groove-forming disk portion B of the roll 11.21.31. It will be processed.

In the above embodiment, three rolling rolls are arranged around the pass line, but four rolling rolls may be arranged. However, arranging two or more than five rolling rolls should be avoided. The reason why the number of rolling rolls is limited to three or four in this way is that when the number of rolling rolls is two,
Due to the rotary forging effect unique to inclined rolling, inclusions,
This is because internal cracks are likely to occur starting from porosity and the like, and the occurrence of internal cracks can be suppressed by using three or more rolling rolls. In addition, when the number of rolling rolls is five or more, the structure of the rolling mill becomes complicated, and the roll diameter or roll shaft diameter cannot be made larger than the material diameter due to the limit of contact (kissing) between adjacent rolls. This is because the strength and locking properties of the machine are reduced, making it impossible to increase the amount of rolling reduction, and dimensional accuracy is also reduced.

Further, in the above-described embodiment, pickling treatment was used to remove the metal oxide on the surface of the first thread forming body 41, but the metal oxide may also be removed by shot processing. . The reason for removing the metal oxide on the surface of the first thread forming body 41 before cold finishing is that if cold finishing is performed without removing the metal oxide, the metal oxide will This is because the metal oxide does not have the same ductility as the base material and does not stretch together with the metal base material during rolling, and peels off during rolling and bites into the metal surface (new surface), causing flaws.

Furthermore, in the embodiments described above, the rolling rolls 11, 21, .
As shown in FIG. 7, the rolling roll 11.21.31 has the disk portion A for forming the groove and the disk portion B for forming the top portion in separate parts. However, if there is a large variation in the height of the thread formed by rough forming by the rolling rolls 1.2.3, rolling with the disc part C may be used. If the finishing process is performed using the rolls 11, 21, and 31, an undesirable bite portion 42a will be formed at the corner of the thread of the second thread forming body 42 as shown in FIG. 8, so the disk portion C is provided. Rolls 11, 21, 31 cannot be used. In this case, a rolling roll 11.21.31 is used in which both the disk portions A and B are provided at separate locations.

When finishing the threads of the second thread forming body 42 using such rolling rolls 11.21.31, the dimensional accuracy of the threads becomes high, and the surface roughness is similar to that of the machined product. or more, and machining (for example, polishing finishing) as a post-process becomes unnecessary. Moreover, the bending of the second thread forming body 42 can also be corrected by this finishing process.

Furthermore, when forming a thread by the method of the present invention as described above, the pitch is 0.20 to 1.0 times the outer diameter of the thread, and the depth of the thread is 0.10 to 0.25 times the outer diameter of the thread. It can be formed regardless of the outer diameter of the thread within the range.

This means that the threads of conventional cold-rolled triangular threads, etc.
The pinch is formed only in the range of 0.03 to 0.20 times the thread outer diameter and the thread depth is 0.01 to 0.10 times the thread outer diameter, and as the outer diameter increases, the outer diameter This shows that the ratio of the thread pitch and the thread depth to the thread is small, whereas the method of the present invention allows threads to be formed in a significantly wider range.

[Numerical example]

Under the conditions listed below, outer diameter: 55. Omm, valley diameter: 39. Owφ, pitch: 14. Omm, Thread angle: 30°, Thread depth: 8 Tsuru metric trapezoidal screw (J
IS BO216-1980) was prototyped.

(i) Material (a) Outer diameter: 60mφ (b) Material: 545C (ii) Hot rolling roll (a) Material: SCM440 (b) Gorge diameter: 200 finφ (maximum part) (c) Inlet face angle α: 11.5゜ (iii) Cold rolling roll (a) Disc material: SKD coated with TiC (b) Disc diameter = 20011φ (maximum) (iv)
Hot inclined rolling conditions (a) Roll crossing angle γ: θ.

(b) Roll inclination angle β: 5° (c) Roll rotation speed: 10100 rpm 2) Heating temperature: 1050°C (V) Pickling treatment conditions (a) Pickling treatment liquid: sulfuric acid (vi) Cold tilt rolling conditions ( B) Roll crossing angle γ, 0 (1) (B) Roll inclination angle β: 6.5° (C) Roll rotation speed: 10100 rp2) Lubrication method
: Machine oil lubrication (E) Reduction amount : 0.5 Tsuru (maximum) As a result of the trial production,
After hot tilt rolling, the dimensional accuracy was ±0.1 mm on the outer diameter and ±0.4% on the pitch, but after finishing by cold tilt rolling, the dimensional accuracy was ±0.03 mm on the outer diameter and ±0.03 mm on the pitch. ±
It became 0.2%. Regarding surface roughness, JIS BOO31 symbol v (Ra: 25μ or less) after pickling treatment.
However, after finishing by cold tilt rolling, the surface became smooth as JIS BOO31 symbol (Ra: 6 μl or less), which was comparable to a finished surface by grinding. Regarding the surface hardness, Hl: 185, which is equivalent to a 545C normalized structure material after hot inclined rolling, became Hl: 208 after finishing by cold inclined rolling.

〔effect〕

As detailed above, according to the method of the present invention, the threads of a thread forming body such as a trapezoidal thread or a square thread are roughly formed by hot working, so the trapezoidal shape, which could not be formed by conventional cold rolling, is formed. Threads with high heights and long pitches, such as threads on thread-forming bodies such as screws and square screws, are formed by plastic working. Furthermore, since the threads are finished by cold tilt rolling, the surface quality, dimensional accuracy, etc. will be equivalent to or better than that of a machined product. As a result, cutting is not required to manufacture threaded bodies such as trapezoidal screws and square screws, thereby improving manufacturing efficiency and reducing manufacturing costs. In addition, unlike conventional threads formed by cutting, the Mi woven fibers are cut.
The thread formed by the method of the present invention has the advantage that its tissue fibers are continuous and its strength is also improved.

[Brief explanation of the drawing]

Figures 1 (a), (b), (c), and (d) are schematic explanatory diagrams showing the implementation state of the method of the present invention, and Figure 2 shows the main parts of the apparatus used to implement the method of the present invention. 3 is a side view showing an enlarged cross section taken along the line ■-■ in FIG. 2; FIG. 4 is a front view showing the main parts of the apparatus used to carry out the method of the present invention;
Figure 5 is an enlarged side view of the cross section taken along the line A schematic explanatory diagram showing the state of forming, FIG. 7 is a side view showing another embodiment of a rolling roll for cold finishing, and FIG. It is a typical explanatory view showing an example of the state where it is processed. 1.2.3...Rolling roll for rough forming 4...Metal material 11,21.31...Rolling roll for finishing forming
4I...First thread forming body 42...Second thread forming body A, B, C...Disk partial patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Tomo Kono (I)
(b) Elaboration 2 Figure (d) ′! J1 figure %3 figure

Claims (1)

[Claims] 1. A rolling roll having a plurality of annular grooves formed in the circumferential direction on the outer circumferential surface for rough forming the thread is arranged around the pass line three times.
The metal material is hot fed between the rolling rolls using an inclined rolling mill equipped with one or four rolling mills, thereby performing inclined rolling on the metal material and roughening threads on its outer circumferential surface. Molding to obtain a first thread-forming body, then removing the metal oxide on the surface of the first thread-forming body to obtain a second thread-forming body, and then finishing the threads. By using an inclined rolling mill in which three or four rolling rolls each having a disk portion for the purpose are arranged around the pass line, the second thread-forming body is coldly fed between the rolling rolls. A method for producing a thread-formed body, characterized in that the second thread-formed body is subjected to inclined rolling to finish the threads on the outer circumferential surface of the second thread-formed body.