JPS6253249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION As shown in FIG. 1, the present invention provides linear legs b, which are protruded from the outer periphery of the curved portion in parallel with the axis at both ends of a closely-fitting helical curved portion c made of an appropriate number of turns.
Automatically continuous while correcting the initial posture of a tension coil spring or a torsion spring with a close spiral part, which has front and rear hooks a and e that have d or do not have straight legs b and d. This relates to a method of molding.

Generally, in order to give an initial tension to a tight tension or torsion coil spring, it is done by deviating the groove center of the oblique forming groove of the curved forming tool that advances to the front side of the feeding hole from the center of the feeding hole. The amount of tension is appropriately determined depending on the magnitude of the initial tension. Special Publication 1977 as a method of applying initial tension to coil springs
No. 620 is known. However, when a coil or straight leg is bent 90 degrees and subsequently a helical section is formed, the deflection is taken to the right in the formation of the helix because the wire flows to the left in the case of right-handed springs. The flow of the wire to be formed is diverted to the right by the slope and notch provided on the right side of the die (FIG. 3), thereby forming a spiral forming part. By the way, the wire rod that is twisted by the diagonal groove for forming and fed with an inclination to the left will have a strong twist in the first turn due to the change in direction, as shown in A in Fig. 4, and then the second turn. There will be gaps due to poor adhesion. In particular, there was a problem in that the wire diameter of the coil spring, which had a large initial tension, was particularly noticeable and could not be used as a product. In addition, since the forming tool for the spiral part is commonly used for production efficiency and economic reasons, twisting occurs due to deviation of the forming diagonal groove that provides the initial tension, as shown in Fig. 4B, and the end of the hook becomes distorted. There was a phenomenon where it bounced sideways.

In view of the above, this invention aims to manufacture a coil spring without the above-mentioned gaps and twists, as shown in FIG.
The present invention solves this drawback and provides a continuous automatic molding method that corrects the posture of the spiral or hook at the beginning of molding to obtain a stable coil spring.

That is, by installing a corrective forming tool or by controlling the movement of some forming tools in two positions, the curved portion of the hook is formed, and the side where the spiral is formed after the hook or straight leg is bent by 90 degrees. The tool is gradually retracted until it comes into contact with the flank of the fine wire and untwisted, and until the first quarter of the curved part of the hook is formed or the first turn of the spiral is formed. It is something.

To explain one embodiment of the device of the present invention,
A wire rod feeding hole 3 is provided in the center, a sliding slope 4 to the right is provided below the feeding hole, and a base 2 (Fig. 3) with a notch 4a provided on the right side is fixed by protruding a certain length from the mounting surface 1. As shown in FIGS. 11 and 12, the upper part of the base 2 on the mounting surface 1 has a wire rod 51 that extends to the front of the feeding hole 3 and collides with the wire 51 that is fed out from the hole 3 to the front side perpendicular to the mounting surface 1. Then, by sliding it on the sliding slope 4 and feeding it into the notch 4a, it is formed into a spiral shape with a constant radius, forming a spiral curved part c having an appropriate number of turns as shown in FIG. The forming tool 5 is installed. The tool 5 can be curved by 180 degrees, curved by 90 degrees, or formed into a helical curved portion by adjusting the time of advancing, staying and retracting to the positions shown in FIGS. 11 and 12 and the feeding speed of the wire rod 51. Be free. Further, in the case of right-handed winding in this embodiment, the groove center of the diagonal groove 5a is deviated to the right from the center of the feeding hole 3, and the amount of deviation is appropriately determined by the magnitude of the initial tension of the spring. At the diagonally upper right corner of the mouthpiece 2, there is a spacer extending to a first position in contact with the flank of the wire rod 51 at the front of the feed-out hole 3 as shown in FIGS. 6 and 13, and immediately before the feed-out hole 3 as shown in FIG. The first forming tool 6 timely advances to the second position to cut the wire 51 across the
will be established. A vertical surface 9 in contact with the wire rod 51 is provided on the distal end surface of the tool 6, extending from a portion corresponding to the center side of the feeding hole 3 to approximately half the length of the outer diameter of the helical curved portion c. There is. On the left side of the cap 2, there is a thick wire rod 51 that moves in the left and right horizontal directions and is parallel to the vertical plane 9 of the tip of the first forming tool 6 in the first position at the advanced position shown in FIGS. 6 and 13. A forming auxiliary tool 7 is provided which produces a spacing corresponding to the width.

The diagonally lower left part of the mouthpiece 2 has a first position where the tip advances as shown in Figs. 6 and 13, and a position shown in Fig. A second forming tool/correction forming tool 8 that appropriately advances to a second position protruding from the left flank of the helical curved portion c or the hook by approximately the diameter of the hook.
will be established. The amount of protrusion of the end of the tool 8 to the second position is appropriately determined in accordance with the amount of deviation of the oblique forming groove 5a so as to obtain the amount of correction that will bring the flow direction of the line into the best condition. Of course, the amount of protrusion may be greater than or equal to the wire diameter depending on the shape of the spring.

Each of the above-mentioned parts produces a harmonious operation as described in the embodiment example of the molding direction described below.

Next, a method for continuously forming a tension coil spring with hooks at both ends using the above-mentioned continuous automatic forming apparatus for coil springs will be described.

From the feeding hole 3 of the mouthpiece 2, a wire 51 is fed at a variable feeding speed depending on the work program.
Bring out. As shown in FIG. 7, at the beginning of forming, the wire rod 51 is slightly fed out from the cut end, and then the curved forming tool 5 advances to the front of the feeding port, and at the same time, the second forming tool/straightening forming tool 8 is moved to the second position. (FIG. 8), and the first semicircular first curve A of the wire 51 is straightened and formed by about a quarter of its circumference. That is, the second forming tool/straightening forming tool 8 in the second position is gradually retracted, the contact is completed after one quarter of the circumference, and the remaining bending is then performed using only the bending forming tool 5, and then immediately withdrawn upward. After that, the wire rod 51 is fed out in a straight line to form the front hook a and the straight leg portion b as shown in FIG. 12
Advance the wire rod 51 as shown in the figure, apply a second bend b of 90 degrees to the straight leg part b, then immediately withdraw it, and replace it with the first forming tool 6.
Advance the forming auxiliary tool 7 to the advanced position and the second forming tool/correction forming tool 8 to the first position as shown in FIG. 13 (FIG. 6), and A third curve C is formed by sandwiching the curve B between the vertical plane 9 of the tip and the tip of the forming auxiliary tool 7 and bending the leg b by 90 degrees to the right at the tip of the second forming tool/correction forming tool 8. Immediately after performing the process as shown in Figures 14 and 14, the first forming tool 6 and forming auxiliary tool 7 are returned to their original positions as shown in Figure 15, and the curved forming tool 5 is moved in place as shown in Figures 9 and 12. 15th, 16th,
As shown in Figure 17, the second forming tool/correction forming tool 8 is moved back to the second position to form the helical part while correcting the first turn or less, usually 1/2 to 3/4 turn. (Figure 15). That is, the second forming tool/correction forming tool 8 in the second position is gradually retracted.
After the contact is completed at 1/2 to 3/4 turns, the front hook a is turned round and round by the bending tool 5, and the required number of turns of the helical curved part c is sent out to the right as shown in FIG. 18. That is, the second forming tool/correction forming tool corrects the twist of the wire which is tilted to the left while being twisted and formed in the oblique groove 5a, and the direction of flow is changed so that the wire sticks closely to the notch 4a of the cap 2.

After that, the curve forming tool 5 is removed to form the straight leg part d of the rear hook e in front of the feeding hole 3 as shown in FIG. 19, and at the same time, the front hook a, the spiral curved part c, etc. It moves to the front side of the mouthpiece 2 as shown by the line, and then, as the bending tool 5 advances for the fourth time as shown in FIG. 20, a semicircle is formed at the rear end of the straight leg d as shown in FIGS. 20 and 21. A fourth curve D is formed.

At this time, if necessary, the second forming tool/correction forming tool 8 may be advanced to the second position to perform correction in the same manner as in the case of the first curve A. When forming curve 2, the helical curved portion c, etc., which had been moving forward from the mouthpiece 2 as shown in FIG. 21, and move the rear hook e forward as shown in the arrow in FIG. 21 to form a short straight section following the fourth curve d. Cut the rear hook e. The cut spring forms the fifth bend E in the post-stroke.

In the embodiment example, FIGS. 13, 14,
Although the feeding of the wire is temporarily stopped during the bending and cutting shown in FIG. 22, the feeding speed is arbitrarily controlled or stopped in other steps as well. It goes without saying that this invention can be applied to cases where the hook is a double loop or a close contact torsion spring.

The present invention has the above-described configuration, and corrects the phenomenon in which the hooks bounce sideways in the manufacture of a coil spring with hooks at both ends as shown in FIG. It is characterized by preventing the winding from coming into close contact with the second winding and creating a gap, thereby obtaining a tight coil spring with a stable shape and quality. In addition, as a specific example of using a straightening forming tool in a spring forming device, an example in which the second forming tool is also used as a straightening forming tool is shown above. Of course, the same effect can be obtained even if the spring forming device is set so that they are in contact with each other.

[Brief explanation of the drawing]

The accompanying drawings show embodiments of the invention, FIG. 1 being a perspective view of a coil spring with hooks at both ends, FIG.
The figure is a front view of the device, FIG. 3 is a perspective view of the base 2, FIG. 4 is a perspective view of a coil spring when the forming method of the present invention is not used, a part of a side view, and FIG. 5 is a perspective view of the coil spring according to the present invention. A perspective view and a part of a side view of the coil spring when the forming method is used, and FIG. The front view shown and FIGS. 7 to 22 are explanatory diagrams showing the manufacturing method in the order of steps.
Figures 1, 13, 15, 16, 18, and 22 are shown in front views, and the others are shown in side views. 2... Mouthpiece, 3... Feeding hole, 5... Curved forming tool, 6... First forming tool, 7... Forming auxiliary tool,
8... Second forming tool and correction forming tool, 9... Vertical surface, a... Front hook, b, d... Straight leg part, c
...Spiral curved part, e...Rear hook.

Claims (1)

[Claims] 1. The wire rod is fed out from the feeding hole of the die, which has a notch parallel to the feeding hole and has a sliding slope below which the coil formed in the notch is fed, by varying the feeding speed, and the wire is fed through the feeding hole. The curved forming tool has an oblique groove for curved forming that is inclined with respect to the axis of the drawing hole, and is provided so as to be able to move forward and backward from the upper side of the feeding hole. In forming a coil spring in which the wire material is brought into contact with the diagonal groove by advancing to the front side of the hole to form a spiral shape, forming a curved portion of the hook of the spring provided with the hook or forming a hook, a straight leg portion or the hook. As the straight leg of the spring that is not provided is bent at right angles to form a helical part, the curve forming tool advances to the front of the feeding hole, and the notch is formed on the sliding slope side under the front feeding hole of the mouthpiece. A corrective forming tool, which can be moved forward and backward from the opposite side, is positioned at a position where the flank of the wire on the side where the spiral is being formed comes into contact and the twist at the beginning of the winding is corrected. or, gradually retracting the corrective forming tool until the first turn of the spiral is formed;
After that, use the curve forming tool to form the remaining hook curved part,
A coil spring characterized in that a spiral portion is formed so that the hook of a spring with a hook or a spring with a straight leg portion without a hook is not twisted and there is no gap at the beginning of winding of the spiral portion. Continuous automatic molding method.