JP2016133136A - Special double nut for looseness prevention - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improvement plan of a double nut including a looseness prevention function with an eccentric fitting structure.SOLUTION: A special double nut for loosen prevention includes upper and lower nuts 2, 3 having screw holes 21, 31 respectively, and an intermediate ring 4 arranged between the upper and lower nuts 2, 3. In the lower nut 2, a support projection part 23 having an outer peripheral surface to which the intermediate ring 4 is externally fitted is provided concentrically with the screw hole 21, and in the upper nut 3, a recess part 32 having an inner peripheral surface to which the intermediate ring 4 is internally fitted is provided concentrically with the screw hole 31. The outer peripheral surface and inner peripheral surface of the intermediate ring 4 are eccentric to each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a special double nut having a locking function.

  The applicant of the present application has been developing a special locking nut that exhibits a high locking function, and has been disclosed in, for example, Patent Document 1 below.

  As shown in FIG. 5, the hard lock nut (registered trademark) includes a lower nut 2 and an upper nut 3 having screw holes 21 and 31 into which a screw shaft 1 of a bolt is screwed. The upper nut 3 is provided with a convex portion 22 protruding upward, and the lower surface of the upper nut 3 is provided with a concave portion 32 into which the convex portion 22 of the lower nut 2 is fitted. The outer peripheral surface of the convex portion 22 and the inner peripheral surface of the concave portion 32 are formed in a tapered shape. Further, the convex portion 22 is slightly eccentric with respect to the screw hole 21, and the upper and lower nuts 2, 3 are horizontally aligned with each other along the eccentric direction by the eccentric fitting between the convex portion 22 and the concave portion 32 of the upper nut 3. More specifically, a horizontal force in the direction opposite to the eccentric direction (left direction in the figure) acts on the lower nut 2, and more specifically in the eccentric direction (right direction in the figure) on the upper nut 3. A horizontal force acts, and a large locking action is generated by these horizontal forces.

  The screw holes 21 and 31 are respectively radially inward from the outer peripheral surface of the convex portion 22 or the inner peripheral surface of the concave portion 32, and the convex portion 22 is eccentric with respect to the screw hole 21. The thickness of the convex portion 22 is gradually increased toward the eccentric direction (right direction in the figure) of the convex portion 22 with respect to the screw hole 21, and a part of the circumferential direction opposite to the eccentric direction. The convex part 22 is the thinnest in the left part of the figure.

Japanese Patent Publication No. 3-526

  As a method of manufacturing the lower nut 2 having the eccentric convex portion 22 of the conventional hard lock nut, a method of integrally forming the eccentric convex portion 22 together with the lower nut body (hexagon nut portion) by forging, or an eccentric convex portion 22 A method of forming by cutting is known. However, in the method of integrally forming the eccentric convex portion 22 by forging, since the convex portion 22 has a shape in which the thickness is biased along the circumferential direction, the metal material constituting the convex portion 22 is biased in the eccentric direction during forging. On the other hand, the hexagonal nut part has the inherent problem that it is preferable to flow the metal material uniformly in the circumferential direction. Moreover, in the case of the method of forming the convex part 22 by cutting, there is a problem that a cutting process is required after forging, resulting in an increase in manufacturing cost due to an increase in the number of manufacturing processes.

  Further, due to the eccentric fitting between the convex portion 22 and the concave portion 32, the outer peripheral surface of the convex portion 22 and the inner peripheral surface of the concave portion 32 are strongly pressed in part in the circumferential direction, but the upper nut 3 is tightened to a predetermined position. At that time, a large frictional heat is generated at the pressure contact portion between the outer peripheral surface of the convex portion 22 and the inner peripheral surface of the concave portion 32, and the metal material constituting the nut is melted by this frictional heat, and the upper nut 3 and the lower nut 2 are welded. There was a case.

  The present invention proposes a new improvement of the hard lock nut in order to solve the above problems.

  In order to achieve the above object, the present invention takes the following technical means.

  That is, the loosening prevention special double nut of the present invention includes a lower nut having a screw hole, an upper nut having a screw hole, and an intermediate ring disposed between these upper and lower nuts, and is provided on either of the upper and lower nuts. A convex portion having an outer peripheral surface on which the intermediate ring is fitted is provided concentrically with the screw hole, and on the other side, a concave portion having an inner peripheral surface on which the intermediate ring is fitted is provided concentrically with the screw hole, The outer peripheral surface and the inner peripheral surface of the intermediate ring are eccentric from each other. According to the present invention, it is not necessary to provide uneven thickness portions on the lower nut and the upper nut, and the upper and lower nuts can be easily manufactured with high dimensional accuracy by forging. Moreover, since it is not necessary to provide a hexagon nut part in the intermediate ring whose thickness changes along the circumferential direction, such an intermediate ring can be easily manufactured with high dimensional accuracy by forging. And, by decentering the outer peripheral surface and inner peripheral surface of the intermediate ring from each other and fitting between the convex and concave portions of the upper and lower nuts, a large loosening prevention by the eccentric fitting equivalent to the conventional hard lock nut An effect can be produced.

  In the special locking nut according to the present invention, the intermediate ring may be fitted to the convex portion and the concave portion so as to be rotatable relative to each other around their axis. According to this, the intermediate ring can be made of a different material from the upper and lower nuts (for example, copper, brass, 6,6-nylon, etc.), and the occurrence of heat welding is caused by the different materials in contact with each other. It is possible to prevent the frictional heat generated when tightening the upper nut against the lower nut on the outer peripheral surface side and inner peripheral surface side of the intermediate ring. It is possible to disperse the inside and outside of the metal, thereby reducing the welding of the pressure contact portion due to the eccentric fitting.

  The outer peripheral surface of the convex portion may be a tapered surface that gradually decreases in diameter toward the tip side, and the outer peripheral surface of the intermediate ring may be a tapered surface having a larger taper angle than the outer peripheral surface of the convex portion. . According to this, the intermediate ring can be smoothly fitted to the convex portion, and the taper angle of the outer peripheral surface of the intermediate ring is made larger than the taper angle for smoothly fitting the intermediate ring to the convex portion. Thus, a large eccentric fitting force between the outer peripheral surface of the intermediate ring and the concave portion can be generated. Furthermore, since the taper angle between the outer peripheral surface of the convex portion and the inner peripheral surface of the intermediate ring is small, even if a large axial force and a pressing force in the horizontal direction are applied during eccentric fitting, the intermediate ring is relative to the convex portion. It is easy to rotate and can effectively dissipate frictional heat.

  In addition, the inner peripheral surface of the recess is a tapered surface that gradually increases in diameter toward the tip side, and the inner peripheral surface of the intermediate ring is a tapered surface having a larger taper angle than the inner peripheral surface of the recess. Also good.

  According to the present invention, it is possible to reduce the product cost by increasing the efficiency of manufacturing the hard lock nut, and to reduce the occurrence of welding due to frictional heat by dispersing the frictional heat generation sites during fastening.

It is a half section exploded front view showing a locking special double nut concerning one embodiment of the present invention. It is sectional drawing of the fastening state of the loosening prevention special double nut. It is a disassembled perspective view of the same locking stopper special double nut. It is a half cross-section exploded front view which shows the locking special double nut which concerns on another embodiment of this invention. It is sectional drawing of the conventional hard lock nut.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to FIG. 3, the special double nut for preventing loosening according to the embodiment of the present invention includes a lower nut 2 having a screw hole 21 penetrating the shaft central portion and an upper screw hole 31 penetrating the shaft central portion. The nut 3 is constituted by an intermediate ring 4 disposed between the upper and lower nuts 2 and 3. The upper and lower nuts 2 and 3 are preferably made of stainless steel or steel, and the intermediate ring 4 is preferably made of a material different from that of the upper and lower nuts 2 and 3, such as copper, brass, or nylon.

  The lower nut 2 has a structure in which a cylindrical support convex portion 23 protruding upward is integrally formed on the upper surface of a hexagonal nut-shaped nut body, and the screw hole 21 is provided at the central portion of the shaft of the convex portion 23. The cylindrical outer peripheral surface of the convex portion 23 is disposed concentrically with respect to the screw hole 21.

  The intermediate ring 4 has a cylindrical inner peripheral surface that fits the outer peripheral surface of the convex portion 23, and is fitted on the convex portion 23 of the lower nut 2 so as to be relatively rotatable from above. In order for the intermediate ring 4 to be smoothly attached to the convex portion 23, the outer peripheral surface of the convex portion 23 is preferably a tapered surface that gradually decreases in diameter toward the upper end side (front end side).

  The cylindrical outer peripheral surface of the intermediate ring 4 is formed in a state slightly decentered with respect to the inner peripheral surface. Therefore, the radial thickness of the intermediate ring 4 gradually changes along the circumferential direction. The outer peripheral surface of the intermediate ring 4 is a tapered surface that gradually decreases in diameter as it reaches the upper end side (tip side), and the taper angle of this outer peripheral surface is the convex outer peripheral surface and the intermediate ring inner peripheral surface. It is larger than the taper angle.

  The upper nut 3 has a structure in which a concave portion 32 is provided on the lower surface of a hexagonal nut-shaped nut body. The inner peripheral surface of the concave portion 32 is a tapered surface adapted to the outer peripheral surface of the intermediate ring 4, and the diameter of the concave portion 32 is It is larger than the diameter of the screw hole 31. The intermediate ring 4 is fitted into the recess 32 so as to be relatively rotatable from below. Further, the inner peripheral surface of the concave portion 32 is provided concentrically with the screw hole 31, and when the uneven thickness intermediate ring 4 is eccentrically fitted to the concave portion 32, a large locking action due to the wedge effect occurs.

  On the other hand, when a large frictional force is generated at the press contact portion between the outer peripheral surface of the intermediate ring 4 and the inner peripheral surface of the recess when the upper nut 3 is fastened, the intermediate ring 4 rotates relative to the lower nut 2 to generate large frictional heat. Can be prevented from concentrating on the pressure contact portion, and can be prevented from being fixed by heat welding.

  The present invention is not limited to the above-described embodiment, and the design can be changed as appropriate. For example, it is possible to provide the convex portion on the upper nut and the concave portion on the lower nut. Moreover, as shown in FIG. 4, it is also possible to make the taper angle of the inner peripheral surface of the intermediate ring 4 larger than the taper angle of the outer peripheral surface.

Claims (4)

  A lower nut having a screw hole, an upper nut having a screw hole, and an intermediate ring disposed between the upper and lower nuts, and one of the upper and lower nuts having an outer peripheral surface on which the intermediate ring is fitted. A concave portion having an inner peripheral surface into which the intermediate ring is fitted is provided concentrically with the screw hole, and an outer peripheral surface and an inner peripheral surface of the intermediate ring are provided A special double nut that prevents loosening, characterized by being eccentric from each other.   2. The special locking nut according to claim 1, wherein the intermediate ring is fitted to the convex portion and the concave portion so as to be relatively rotatable around their axial centers, respectively. 3. .   3. The special double nut for preventing loosening according to claim 1, wherein the outer peripheral surface of the convex portion is a tapered surface that gradually decreases in diameter toward the tip side, and the outer peripheral surface of the intermediate ring is more than the outer peripheral surface of the convex portion. A special double nut to prevent loosening, which has a tapered surface with a large taper angle.   3. The special double nut for preventing loosening according to claim 1, wherein the inner peripheral surface of the recess is a tapered surface that gradually increases in diameter toward the tip side, and the inner peripheral surface of the intermediate ring is the inner peripheral surface of the recess. A special double nut to prevent loosening, which has a tapered surface with a larger taper angle.

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