JPS631141B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a locking nut that can prevent loosening after being screwed onto a bolt, etc., and particularly provides a good locking torque. The present invention relates to a method for manufacturing nuts with relative ease and at low cost.

(Prior Art) Conventionally, a method of manufacturing a locking nut as shown in FIG. 4, for example, is known. This is done by digging one end of the nut material 11 into a circular shape with a diameter larger than that of the screw hole to an appropriate depth, and then forming a recess 12 and a crown part 13.
After cutting out the part corresponding to the outer corner corner of this coronal part 13 in a V-shape, the coronal part 13 is compressed in the axial direction with mold D and bent inward, and the tip of the coronal part 13 is cut out. A substantially circular opening 14 is formed, and this opening 14
A thread 13a equivalent to the threaded hole 11a of the nut material 11 is formed on the inner periphery of the nut material 11, and the opening 14 is further compressed in the axial direction using the same mold D as that used before.

(Problems to be Solved by the Invention) In the conventional method for manufacturing the locking nut described above, the step of cutting out the portion corresponding to the outer corner corner of the crown portion 13 in a V-shape is a bottleneck for continuous machining, and the manufacturing process is troublesome. This increases the cost, and since the corners on both sides of the cut-out portion contact the surface of the bolt at an acute angle when screwed together with the bolt, this portion scrapes the thread of the bolt and generates chips. There was a problem in that the chips were likely to get caught up in the threaded portion and cause seizing.

The present invention has been made in view of the above-mentioned conventional problems, and eliminates the step of cutting the portion corresponding to the outer corner corner of the coronal part in a V-shape, and instead performs simple outer circumferential cutting. This is an attempt to solve conventional problems.

(Means for Solving the Problems) In the present invention, in order to solve the above conventional problems, one end side of the polygonal nut material 1 is dug to an appropriate depth into a circle having a larger diameter than the screw hole 1a thereof. A crown-shaped portion 3 is formed, and as a result, the crown portion 3 has a thick wall at a position corresponding to the corner portion 1b of the nut material 1.
A process of forming a thin part at a position corresponding to the flat part 1c, and cutting the outer periphery of the crown part 3 into a conical shape so as to expand toward the other end of the nut material 1, and as a result, the part of the crown part 3 is The process of forming the meat so that it is thinner on the distal side and thicker on the proximal side, and the crown part 3
A type D with a curved recess Da having an approximately circular cross section.
a step of squeezing the opening 4 in the axial direction and bending it inward, thereby deforming the thinner part corresponding to the flat part more inwardly than the thicker part corresponding to the corner part to form a non-circular opening 4; A step of forming a thread 3b equivalent to the thread of the nut material 1 on the inner periphery of the non-circular opening 4 of the part 3, and compressing the crowned part 3 in the axial direction again with the mold D to slightly reduce the opening 4. At the same time, a method including the step of forming the opening into a non-circular shape again in the same manner as described above was employed.

(Function) In the method of the present invention, one end of the polygonal nut material 1 is dug to an appropriate depth in a circular shape with a larger diameter than the screw hole 1a thereof by a method such as spot boring to form the crown portion 3. In this way, a portion is formed in the crown-shaped portion 3 where the thickness is thick at a position corresponding to the corner portion 1b of the nut material 1, and where the thickness is thin at a position corresponding to the flat portion 1c. Next, instead of the conventional V-shaped cutting process, the outer periphery of the crown part 3 is cut into a conical shape that expands toward the other end of the nut material 1. In this way, the thickness of the coronal portion 3, particularly in the thick portion corresponding to the corner portion 1b, becomes thinner toward the distal end and thicker toward the proximal end. Next, the crown part 3 is compressed in the axial direction with a mold D to bend it inward, and as a result, the relatively soft thin part is deformed more inward than the thick part, so that it has a shape that is approximately similar to the outer shape of the nut material 1. Next, a thread 3b equivalent to the threaded part 1a of the nut material 1 is formed on the inner periphery of the non-circular opening 4, and then the crown part 3 is again compressed in the axial direction with the mold D. Then, the opening 4 is slightly reduced in size, and the opening 4 is again formed into a non-circular shape by the same action as the first compression, thereby producing a locking nut. The thus manufactured nut obtains a locking torque by partially tightening the bolt through the non-circular opening 4 in the crown 3. In addition, good overall elasticity is obtained by varying the wall thickness of the crown portion 3 in the circumferential direction. Due to the partial tightening of the bolt by the non-circular opening 4 and the variation of the spring force in the circumferential direction of the crown 3, the tightening force on the bolt is not uniform over its entire circumference and there is no elastic recovery in the radial direction. The force is also not uniform over the entire circumference of the crown portion 3, and seizure to the bolt is more effectively prevented than in the case where the bolt is tightened equally over the entire circumference.

(Example) An embodiment of the present invention is shown in FIGS. 1 to 3.

Figures 1A to E are front views and plan views showing the manufacturing process of the locking nut in order, Figure 2 is a sectional view of Figure 1B, and Figure 3 is the
It is a cross-sectional view in Figure B.

In the method of this embodiment, as shown in FIG. 1A, first, one end side of the hexagonal nut material 1 is dug into a circular shape concentric with the screw hole 1a of the hexagonal nut material and having a larger diameter than the screw hole 1a. and a crown-shaped portion 3. Since the nut material 1 has a polygonal shape, the crown part 3 is
The nut material 1 is formed to have a thick wall at a position corresponding to the corner portion 1b and a thin wall at a position corresponding to the flat portion 1c.

Next, as shown in FIG. 1B, the outer periphery of the crown part 3 is cut into a conical shape that widens toward the other end of the nut material 1, and a slope 3a is formed around the position corresponding to the corner part 1b.
form. In this state, an annular rim of approximately equal thickness is formed at the distal end of the crown part 3 over its entire circumference, but on the base side, as well shown in FIGS. 2 and 3, a nut material 1, the meat is thick at the position corresponding to the corner 1b, and a thin part is left at the position corresponding to the flat part 1c. Therefore, at the position corresponding to the corner 1b, the meat is thinner on the distal side and thicker on the proximal side. . That is, by cutting the conical shape, a hexagonal portion is left on the outer periphery base side of the coronal portion 3, and a thick portion X and a thin portion Y are formed. The thin portion Y has a uniform thickness from the tip to the base.

Next, as shown in FIG. 1C, the coronal portion 3 is compressed in the axial direction using a mold D having a recess Da having a substantially semicircular cross section, and the tip portion is bent inward. At this time, since the portion corresponding to the corner portion 1b gradually expands outward toward the base, the outer circumference of the crown portion 3 is uniformly shaped into the shape D.
Do not come into contact with. That is, it is considered that the portion corresponding to the corner portion 1b contacts the mold D with greater pressure. However, since the portion corresponding to the corner portion 1b is thick and therefore relatively strong, the deformation due to compression is concentrated in the portion corresponding to the flat portion 1c, which is relatively thin, and this portion is slightly larger than the other portions and is relatively strong. overhang to. As a result,
The outer shape of the nut material 1 (6
A non-circular opening 4 having a substantially similar shape to the rectangular shape is formed.

Next, as shown in FIG. 1D, a thread 3b identical to the threaded part 1a of the nut material 1 is carved on the inner periphery of the non-circular opening 4 of the crown part 3. In this embodiment, the threaded portion 1a of the nut material 1 is threaded in advance, but it is also possible to thread the threaded portion 1a of the nut material 1 at the same time as the threaded portion 3b in this step.

Next, as shown in FIG. 1E, the coronal part 3 is compressed in the axial direction slightly deeper than before using the same mold D as described above, and the opening 4, which has returned to a substantially circular shape by cutting the tip, is slightly reduced, and The opening 4 is formed into a non-circular shape again by the same action as described above, and at the same time, the pitch of the screw 3b is slightly shifted in the compression direction. In this way, the locking nut is completed.

(Effects of the Invention) As described above, in the present invention, the crown part 3 is formed by digging one end of the polygonal nut material 1 into a circle with a larger diameter than the screw hole 1a to an appropriate depth, and as a result, the crown part 3 is formed into a crown part 3. forming a part 3 in which the meat is thick at a position corresponding to the corner part 1b of the nut material 1 and where the meat is thin at a position corresponding to the flat part 1c;
A process of cutting the outer periphery of the crown part 3 into a conical shape so as to expand toward the other end of the nut material 1, and as a result, forming the flesh of the crown part 3 so that it becomes thinner toward the distal end and thicker toward the proximal end. , the coronal part 3 is compressed in the axial direction by a mold D having a curved recess Da with a substantially circular cross section and bent inward, so that the thin part corresponding to the flat part is made smaller than the thick part corresponding to the corner part. a process of greatly deforming the crown part 3 inward to form a non-circular opening 4;
A step of forming a thread 3b equivalent to the thread of the nut material 1 on the inner periphery of the non-circular opening 4, and compressing the crown part 3 in the axial direction again with the mold D to slightly reduce the opening 4, Again, since a method including the step of forming the opening 4 into a non-circular shape as described above is adopted, the troublesome step of cutting the corner into a V-shape in the conventional method is omitted, and the locking nut can be easily and inexpensively manufactured. The resulting nut has a non-circular shape with a partial inner bulge in the opening 4 of the crown 3, and the inner bulge allows the bolt to be tightened and loosened. A stopping torque is generated. Since this inner protruding portion does not extend over the entire circumference of the opening 4, the tightening force against the bolt is not uniform over the entire circumference, and there are thick and thin portions on the base side of the crown portion 3. Since the elastic restoring force in the radial direction is not uniform over the entire circumference of the crown part 3, it is more effective in preventing seizure when screwed into the bolt than when tightening the bolt equally over the entire circumference. can be prevented. Furthermore, the inner periphery of the opening 4 is relatively thin over the entire circumference, so the area that rubs against the bolt is small, and there is no cutout such as a slot on the periphery of the opening 4, so there is no risk of scraping the outer periphery of the bolt. This is also effective in preventing burn-in. Furthermore, although the inner circumferential edge of the opening 4 of the coronal portion 3 is relatively thin over the entire circumference, there are parts on the base side that are thick and have hard spring characteristics, and parts that are thin and have soft spring characteristics. The portions having the locking portions are alternated in the circumferential direction, and their interaction provides an appropriate overall spring force for obtaining the locking torque.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention, and Figures 1A to E are front views and plan views showing step by step the manufacturing process of a locking nut, and Figure 2 is a top view. Figure 1B is a cross-sectional view, Figure 3 is a cross-sectional view of Figure 1B, and Figure 4A is a cross-sectional view of Figure 1B.
9 to E are a front view and a plan view showing the manufacturing process of a conventional locking nut in order. 1...Nut material, 1a...Threaded part, 1b...
Corner, 1c...Plan view, 2...Recess, 3...Coronal part, 3a...Slope, 3b...Threaded part, 4...Opening, D...Shape, Da...Recess.

Claims (1)

[Scope of Claims] 1. One end of the polygonal nut material is dug into a circle with a larger diameter than the screw hole to an appropriate depth to form a crown, and as a result, the crown is provided with meat at a position corresponding to the corner of the nut material. a process of forming a part with a thick part and a thin part at a position corresponding to the flat part, and cutting the outer periphery of the crown part into a conical shape so as to expand toward the other end of the nut material, and as a result, the flesh of the crown part is forming the coronal part to be thinner on the distal side and thicker on the proximal side; squeezing the coronal part in the axial direction with a mold having a curved recess with a substantially circular cross section and bending it inward;
As a result, forming a non-circular opening by deforming the thin part corresponding to the flat part more inwardly than the thick part corresponding to the corner part; forming a thread substantially equivalent to the threaded hole in the nut material, compressing the crown part in the axial direction with the mold again to slightly reduce the opening, and making the opening non-circular again in the same manner as above; A method for manufacturing a locking nut, comprising the steps of: 2. The method for manufacturing a locking nut according to claim 1, wherein the outer periphery of the nut material is hexagonal. 3. Claim 1, characterized in that in the step of compressing the coronal portion in the axial direction with the mold again, the pitch of the screw formed on the inner periphery of the opening is slightly shifted in the compressing direction. A method for manufacturing a locking nut described in . 4. The locking nut according to claim 1, wherein the threaded hole in the polygonal nut material is formed at the same time as the thread is formed in the inner periphery of the non-circular opening of the crown part. manufacturing method.