JPS635835A - Rolling method for grooved screw and rolling flat dies - Google Patents

Abstract

PURPOSE:To manufacture in a short time the grooved screw of a self-fixing type by the die providing in continuation the rear side part where the large screw crest groups for finishing are arranged in parallel at the two times intervals of the small screw crest groups for subworking at the rear part of the front side part where the small screw crest groups for subworking are arranged in parallel at the equal intervals. CONSTITUTION:The small screw crest 3 groups for subworking inclining in coincidence with a screw spiral lead angle are extended with their projection in parallel at the equal interval pitch P1 on the inner side face 2 of the front half part in the moving direction of the die plate 1 of the working time. The large screw crest 5 groups for finishing continuing in a series extension shape one by one of the small screw crest 3 groups for subworking on the inner side face of the half part is thereafter extended with their projection in parallel continuously at the two times pitch 2P1 of the small screw crest 3 groups for subworking. A round bar is set by pinching it from both sides to the start end side in the moving direction respectively with a pair of rolling flat dies thus composed, and the self-fixing type grooved screw having the groove elastically deforming at the crest part of the large screw on the outer peripheral face of the rotating round bar is manufactured by transferring the mutual rolling flat dies in the shape of passing each other with pinching the round bar.

Description

Detailed Description of the Invention (1) Purpose of the Invention [Field of Industrial Application] The present invention relates to screw members such as bolts and nuts, particularly self-locking screws that can prevent loosening after tightening. This invention relates to a method for rolling a grooved screw related to a threaded member and a flat rolling die used directly for carrying out the method.

[Prior art] Conventionally, as this type of self-fixing screw member,
-19492 publication, JP-A-54-65252 publication,
Japanese Unexamined Patent Publication No. 58-28008 and Utility Model Application No. 60-58
Grooved screw members described in Japanese Patent No. 913 are known. The basic structure of these self-fixing screw members is that the threaded part has a groove cut in the radial direction from the tip, and the part facing the groove with a lυ is a male member with a different flank angle. The screw and female screw member are elastically deformed due to the pressure contact when they are screwed together, and the screw contact surface is deformed due to the elastic repulsion force at that time. A self-locking effect can be obtained by increasing frictional resistance, but in a self-locking mechanism that relies only on elastic repulsive force due to elastic deformation, the elasticity of the parts facing each other across the groove is When the repulsion force decreases or the state of permanent deformation occurs, the self-locking ability of the screw member is lost during repeated use, which is a fatal drawback. Created an invention and filed a patent application in 1984 under the name of self-fixing screw member.
The application was filed as No. 263223.

That is, in the invention, the screw thread A has, in the axial cross section,
The lower part a1 is divided into a lower part a1 and an upper part a2, and the lower part a1 has both side surfaces that match the flank angle α of the screw, and the upper part a2 has both sides substantially parallel to the radial direction. A groove of a predetermined width is provided in that part, cut in the radial direction from the tip thereof, and in the screwing relationship of the screw member, both sides of the lower part a1 are The upper part a2 is a rigid screw part that contacts the screw member B in a rigid state, and the upper part a2 is elastically deformed and resilient in the direction of reducing the width of the groove. The elastic screw portion is in contact with each other in a state that the rigid screw portion and the elastic screw portion have a synergistic effect to prevent the screw from loosening.

[Problems to be Solved by the Invention] The present invention aims to provide a method for rolling a grooved screw, which is the above-mentioned self-fixing screw member of this type, improved by the present inventor, and a flat rolling die. It is.

(2) Structure of the Invention [Means for Solving Problems] The present invention provides a small screw thread for lower machining that is inclined in accordance with the helical lead angle of the screw on the inner surface of the front half of the die plate in the moving direction during machining. A large screw thread for finishing processing extends in parallel at intervals and extends in parallel on the inner surface of the rear half portion, and is continuous in a linearly extending shape every other small thread thread for preprocessing.
A pair of rolling flat dies extending in parallel at double pitch intervals is used to set a separately prepared round bar on the starting end side of the moving direction from both sides, and the rolling flat dies are slid together while being squeezed. In the case of shifting to a different shape, there is a first step of pre-rolling forming continuous two-thread small screws with equal pitches on the outer circumferential surface of the rotating round bar, and a first step of rolling and pre-forming the two-thread small screws with the same pitch on the outer circumferential surface of the rotating round bar. The two-thread small screw is plastically flowed by gradually passing through a second step of rolling a single-thread large screw at a pitch twice the pitch of the two-thread small screw by overlapping every other thread of the screw. A self-fixing grooved screw is manufactured by forming an elastically deformable groove on the top of the large screw.

[Example] A first example of the rolling flat die of the present invention will be described with reference to FIGS. 1 to 4.

In the rolling flat die of the present invention, the sandwich material on the inside of the front half in the moving direction of the die plate 1 during processing has three groups of small screw threads for lower processing that are inclined on the opposing surface 2 in accordance with the thread lead angle β of the thread thread A. extend parallel to each other with an adjacent interval d and an equal pitch P1, and the pincers on the inside of the rear half are linearly extended on every other group of three groups of small screw threads for finishing machining on the opposing surface 4. Five groups of screw threads are continuously extended in parallel at an interval of 2P1, which is twice the pitch of the three groups of small screw threads for lower processing.

The die plate 1 is made of tool steel, cemented carbide, etc., and the large screw thread 5 for finishing has the same angle as the flank angle α of the small thread 3 for pre-processing, and is higher than the small thread 3 for pre-processing which is lower. In order to smoothly transition to the large screw thread 5 for finishing processing, an ascending slope section 6 is provided at the starting end of the large thread thread 5 for finishing processing as a bridge.

A second embodiment of the flat rolling die of the present invention will be described with reference to FIGS. 5 to 8.

In the rolling flat die of the present invention, the pincer inside the front half of the die plate 7 is a group of 9 small screw threads for preliminary processing on the opposing surface 8, and the pincer inside the rear half is a group of large screw threads for finishing on the relative surface 10. Groups 11 are densely continuous and protrude parallel to each other without adjacent intervals, and the pincers on the inside of the rear half have a relative surface 10, and the pincers on the inside of the front half have a large screw thread 11 for finishing, which is lower than the relative surface 8. The summit line 9- of the small screw thread 9 for preliminary machining and the large screw thread 11 for finishing machining is created by adding a step that is higher than the small screw thread 9 for use. 11- is formed in a continuous horizontal shape, and the other constructions are the same as in the first embodiment.

A third embodiment of the rolling flat die of the present invention is shown in FIGS.
As shown in Figure 0, the clipping material inside the front half of the die plate 12 keeps the protruding height of the small screw thread 14 for preliminary machining of the relative surface 13 constant, and the clipping material inside the rear half serves as the large screw for finishing machining of the relative surface 15. mountain 16
is formed in the inclined part 16' so that the height starts from the height of the small screw thread 14 for preliminary processing and gradually increases until it reaches the final height at least the outer circumference length of the round bar Y from the end.

The fourth embodiment of the rolling flat die of the present invention is shown in FIGS.
As shown in Fig. 2, the pinching material inside the front half of the die plate 17 has a height of zero at the starting end of the small screw thread 19 for pre-machining on the opposing surface 18.
It is formed into an inclined part 19' whose height gradually increases from the terminal end to at least the outer circumferential length of the round bar Y, and the clamping material on the inside of the rear half part has a large screw thread 21 for finishing on the opposite surface 20 which is pre-processed. A slanted part 21' is formed which gradually increases in height from a directly connected starting end that matches the terminal end height of the small screw thread 19 to at least the outer circumferential length of the round bar Y from the terminal end.

Another embodiment of the rolling die of the present invention is one in which heater storage holes or cooling holes H are bored inside the die plate 1, as shown in FIG.

In still another embodiment of the rolling die of the present invention, as shown in FIG.
A round rod seat portion 24 is provided at the starting end of the rod.

An example of the method of rolling a grooved screw according to the present invention using a pair of rolling dies according to the present invention will be described with reference to FIG.

First, vertically or horizontally roll the rolling dies in opposite directions with their starting ends facing each other, and hold a separately prepared metal round bar Y in a vertical or horizontal position so that the sandwiching material inside the front half of the die plate 1.1 is facing each other. Sandwiches are set from both sides between the starting ends of the 3 groups of screw threads for surface 2.2 lower machining, pressure is applied from both sides in the direction of arrow M, and then the die plate 1. If °1 is moved in the direction of arrow N in a trailing or sliding manner, the sandwich material on the inside of the front half of die plate 1. While passing through 2゜2, the first
As shown in Fig. 5, after the first step of rolling and pre-forming a group of two consecutive small screw threads A1 with an equal pitch P1, the sandwich material on the inside of the rear half of the die plate 1°1 is immediately placed on the opposite surface 4.4. As it passes through, it is rolled by five groups of single-thread large screw threads for finishing processing, and is superimposed on every other thread of the two-thread small thread threads of A1 group to form single-thread large thread threads at double pitch 2P1-P. A secondary step of rolling the A group to form a book, and a buffer that plastically deforms the two small screw threads A1 group and elastically deforms them to the center of each peak of the large thread A group through one tier. The grooves are formed to obtain the self-locking grooved screw shown in FIG.

When a pair of die plates 7.7 is used, a self-fixing grooved screw having a buffer groove b' formed at the center of each crest of the group of large screw ridges A' shown in FIG. 19 is obtained.

Furthermore, when a pair of die plates 22.22 as shown in FIG. 14 are used, the opposing circular arc surfaces 24-. It is easy to set the metal round bar Y from above or from the side between 24".

In addition, if the rolling die is used continuously, there is a risk of seizure or galling, so consideration is given to circulating cooling water or other refrigerant through the cooling hole H during operation so that the rolling die does not exceed a certain level of dryness. .

In addition, when the round bar Y material is thermoplastic or thermosetting engineered plastic, a heater (not shown) built in the heater storage hole H of the rolling die is used to move the flat rolling die to the thermoplastic or thermosetting temperature. need to be raised to.

A ceramic material before firing can also be used as the rough round bar Y material.

[Effect] Thus, in the method of rolling grooved screws using the flat rolling die of the present invention, since the first step and the second step are continuous, they can be manufactured all at once, and the time required for setup is shortened. suitable for childbirth.

Incidentally, it is possible to produce about 50 to 120 pieces per minute, and the product viscosity is about grade 2.

Here, an impact loosening test of a grooved screw (hereinafter referred to as a test bolt) manufactured by the rolling method of the present invention using the rolling die of the present invention will be described below.

■Test method a, sample bolt has outer diameter 9.30aa + 1 hardness 290HV
The test nut is equivalent to Niteku M10 and has a 7 day (class 3) inner diameter of 8.6011IIIMM.

Uses 237HV with an effective diameter of 9.21mm.

b. @ Impact loosening test device: Figure 20 schematically shows the structure of its main parts. In the same figure, the test bolt T is attached to the lower cylinder 25.
The head is fixed and tightened with the upper nut 26 to form a screw fastening body. This fastening body is dropped and the upper circle n27 collides with the pedestal 28.

A tensile impact force is generated in the lower cylinder 25 due to the collision, and a compressive impact force generated on the contact surface of the thread A of the bolt nut is transferred to the lower cylinder 25 due to the propagation of the impact stress wave.
Detected by strain gauge G attached to. The force responsible for loosening the screw is compressive impact force.

In the figure, 29 is a spring support, and 30 is a tension rod. 31 is a guide tube, and 32 is a bottle.

#60 spindle oil is applied to the threaded surface of the C1 test bolt T, the threaded surface of the nut 26, and the nut seating surface, and a test is performed. Keeping the tensile impact force constant, measure the number of impacts on the screw fastened body and the bolt axial force.

(2) Results and Discussion By the above method, Figure 21, a and a' are 5,000 continuous impact test data, and impact loosening test characteristic graphs D and E were obtained. In this way, the average value of the 42 test bolts is measured. As shown in Fig. 21, the initial axial force is set to 21.
5KN, and retighten after 1500 collisions.

The average axial force at this point is 20.97 KN, and the bolt begins to untwist after about 1,500 to 2,000 cycles. Then the final 500
The uniaxial force remains almost constant until the 0th cycle. Looking at the final axial force and the average axial force for the 5000th time, it is 20.01 KN. The difference in axial force between the time of retightening and the final time is 0.96
It was KN. Summarizing the above results, it can be seen that the final axial force remains 95% of the ground line axial force.

Next, the collision between the test bolt and the commercially available bolt is Figure 22 shows a comparison of the impact loosening tests.

Figure 22 is a graph F of the impact loosening characteristics of the test bolts, including relief bolts, 80M caps,
At the 2000th time of nut 5KS305, the axial force suddenly increased, 1300kgf, 600kQcj, return torque 10
When the axial force reaches 0kQaj, the axial force decreases to zero and is completely relaxed.

On the other hand, Fig. 23 shows the impact gi 1 loosening characteristics graphs G, H, and I of commercially available bolts. In the case of graph G, the axial force suddenly increases after the 140th use and the 16th time for the SCM bolt, 5KS305 nut, and flat washer. rose to 1300kof,
At the stage where the axial force reached 250 and 9m, the axial force decreased to zero and was completely loosened.Next, in the case of graph H, the 80M cap.

5KS305 Natsu, flat washer 2 after 200th time
By the fifth time, the axial force increased to 13QQkgf and 280kgd, and the axial force decreased to zero and was completely loosened, and in the case of graph I, the 80M cap.

5KS305. Three experimental examples are shown in which the axial force of the flat washer increases to 1300 kOf' and 280 kQcj after the 180th time and 20th time, and then the axial force decreases to zero and completely loosens.

As a result of comparing the two, it was found that the test bolt had an impact loosening strength approximately 10 times higher than that of the commercially available bolt.

[Brief explanation of drawings]

FIG. 1 is an inside front view showing a first embodiment of the flat rolling die of the present invention, and FIGS. 2 to 3. The figure shows the ■-■ line and ■ in Figure 1.
FIG. 4 is a plan view showing the first embodiment of the present invention, and FIG. 5 is an inside front view showing the second embodiment of the rolling flat die of the present invention. 6 and 7 are the vt-Vl line and the Vl line in FIG.
Fig. 8 is a plan view showing the second embodiment of the present invention, and Figs. 9 to 10 are inner front views showing the third embodiment of the flat rolling die of the present invention. Figures and plans, 1st
1 to 12 are an inside front view and a plan view showing a fourth embodiment of the rolling flat die of the present invention. Figures 13 to 14 respectively show construction examples of the rolling method of the present invention, and Figure 15 shows the under-machining formed on the outer circumferential surface of a round bar in the first step of the first construction example of the rolling method of the present invention. Fig. 16 shows the main part of the grooved screw that formed the large thread group for finishing in the same secondary process, and Fig. 17 shows the middle part of the grooved screw. Enlarged cross-sectional view of main parts,
Fig. 18 is a sectional view of the screw thread part in the screwed state, Fig. 19 is an enlarged sectional view of the main part of the thread of another grooved screw,
Fig. 20 is a partially broken schematic explanatory diagram of the impact loosening test device, Fig. 21 is a graph of impact loosening test characteristics of grooved screws, and Fig. 22
Figures 23 to 23 are comparison graphs between a grooved screw and a commercially available bolt, with Figure 22 showing the grooved screw and Figure 23 showing the commercially available bolt. A...Medium thread A1...2 small thread thread A'
...Large screw thread al...Lower part a2...Upper part b1. b
-...Groove C...Opposing portion d...Adjacent interval α...Frank angle β...Lead angle H...Heater storage hole or cooling hole P1...Pitch Y...Round bar 1.7.12.
17.22...Dice plate 2.8, 13.18.23.
...The sandwich material on the inside of the front half is the relative surface 3.9.14.19...Small screw thread for pre-processing 4.10.
15.20... The inner side of the rear half has a relative surface 5.11.16.21... Large screw thread for finishing 6...
・Ascending slope section 9-. 11-...Mountain top line 24...Round bar seat Fig. 1 Fig. 3 Fig. 4 l2 Iffi's engraving (Additional +1 to content Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 18 Fig. 19 Fig. 20 Procedure amendment form) September 2, 1985 Commissioner of the Patent Office Kuro 1) Akio Tono 1, Indication of the case 1986 Patent Application No. 146797 2, Title of the invention Method for rolling grooved screws and flat rolling die 3, Relationship with the case of the person making the amendment Patent applicant address 7-38-23 Minamikoiwa, Edogawa-ku, Tokyo Name
Japan Tokushu Kizai Co., Ltd. 4, Agent 105 Address Nishijin, Minato-ku, Tokyo ! The drawing originally attached to the application form No. 1-20-11 is as attached (no change in content)
I will engrave it.

Claims (1)

[Scope of Claims] 1. On the inner surface of the front part of the die plate in the direction of movement during processing, a group of small screw threads for lower processing, which are inclined in accordance with the helical lead angle of the screw, are extended in parallel at equal pitches and extend in parallel. On the inner surface of the side portion, a group of large screw threads for finishing processing that are continuous in series are extended in parallel from every other small thread thread group for lower processing at a pitch interval twice that of the small thread thread group for lower processing. The grooved screw according to claim 1, wherein the flat rolling die 2 for the grooved screw and the group of small screw ridges for preliminary processing extend in parallel and protrude at a constant interval from each other. Flat rolling die 3 for grooved screws according to claim 1, in which the small thread ridges for lower processing extend continuously and densely in parallel and projectingly with no spacing between them. 4. Grooving according to claim 1, 2 or 3, in which the starting end of the large screw thread group for finishing processing is directly connected to the small thread thread group for lower processing is formed in an ascending slope part. The flat thread rolling die 5 and the large screw thread group for finishing are inclined in height from the directly connected starting end that matches the height of the small thread thread group for lower processing until they are at least the outer circumferential length of the screw in front of the terminal end. A rolling flat die 6 for a grooved screw according to claim 1, 2 or 3, which is formed into a shape, and the die plate has a rear half of the inner surface for lower processing than a front half. The small screw ridges and the large screw ridges for finishing are formed in a stepwise manner as low as the difference in height, so that the tops of the small screw ridges for preliminary processing and the large screw ridges for finishing are aligned on the horizontal line. The rolling flat die 7 for a grooved screw according to claim 1, 2, or 3, formed by forming a group of small screw ridges for preliminary processing, has a starting end with zero height and at least the outer periphery of the screw from the terminal end. The large screw thread group for finishing processing is formed in an inclined shape whose height gradually increases until it reaches the front side by the length, and the large screw thread group for finishing processing has at least a screw thread from the direct connection starting end that corresponds to the terminal height of the small thread thread group for preliminary processing. A flat rolling die 8 for a grooved screw according to claim 1, 2 or 3, which is formed into an inclined shape whose height gradually increases until it reaches the front side by the outer circumference length, and is large for finishing processing. Flat thread rolling die 9 for grooved screws according to claim 1, 2, 3, or 4, wherein the screw thread group has the same angle as the flank angle of the small screw thread group for preliminary processing. Claims 1, 2, 3, 4, and 5, wherein the die plate has a heater storage hole bored therein.
The rolling flat die 10 for grooved screws according to item 1, item 6, item 7, or item 8, and the die plate have cooling holes bored inside.Claims 1 and 2 , the rolling flat die 11 for grooved screws described in item 3, item 4, item 5, item 6, item 7, or item 8, the die plate has a round bar receiving portion at the starting end in the advancing direction. Claims 1, 2, 3, 4,
Flat rolling die 12 for grooved screws as described in item 5, 6, 7, 8, 9 or 10, two consecutive small threads at a predetermined pitch on the outer peripheral surface of a rotating round bar. A first step of pre-rolling and forming a screw, and following the first step, rolling a single-thread large screw at a pitch twice the pitch of the two-thread small screw by overlapping every other thread of the two-thread small screw. A method 13 for rolling a grooved screw in which a buffer groove is formed at the top of the large screw by plastic flow deformation of the two-thread small screw through a secondary step of main forming. , a method 14 for rolling a grooved screw according to claim 12 in which the round bar is in a vertical position, a method 15 for rolling a grooved screw according to claim 12 in which the round bar is in a horizontal position Claim 1: The screw is characterized in that the flank angle of the thread cross section is the same as the flank angle of the thread thread cross section of the small screw.
A grooved screw rolling method 16 according to claim 2, 13 or 14, wherein the round bar material is metal, plastic, or ceramic.Claim 12, 13, 14 or 14 Method for rolling grooved screws described in Section 15