WO2013157338A1

WO2013157338A1 - Double nut

Info

Publication number: WO2013157338A1
Application number: PCT/JP2013/057631
Authority: WO
Inventors: 伊藤　勝夫
Original assignee: イイファス株式会社
Priority date: 2012-04-19
Filing date: 2013-03-18
Publication date: 2013-10-24
Also published as: JP2013224679A; JP5235237B1

Abstract

[Problem] To provide a double nut that can easily be manufactured and whereby manufacturing cost can be minimized by reducing the number of manufacturing steps. [Solution] A double nut (1) configured from: a first nut (2) having a truncated-cone-shaped convex protrusion (22) which decreases in diameter toward the outside from one end face of the nut and is concentric with a female screw hole (21) screwed on a bolt (B); and a second nut (3) having at one end face of the nut a truncated-cone-shaped concave depression (32) into which the protrusion (22) can fit, and which is concentric with a female screw hole (31) screwed on the bolt (B); wherein an eccentric projection (33), in which a portion of an internal peripheral face of the depression (32) protrudes inward so as to be able to press on an external peripheral face of the protrusion (22) when the protrusion (22) is fitted in the depression (32), is formed in the second nut (3).

Description

Double nut

The present invention relates to a double nut used for loosening when a nut is fastened to a bolt.

¡Double nuts have a function to prevent loosening of nuts by friction force generated when another nut is fastened on top of a nut fastened to a bolt, and both nuts are pressed. In such a conventional common double nut, a convex portion protruding from an end portion is provided on one nut, and a concave portion into which the convex portion can be fitted is provided on the other nut, and the convex portion or the concave portion is provided. One of these is eccentric. With this configuration, when both nuts are fastened, there is an effect that the nut is difficult to loosen due to frictional resistance at the pressure contact surface generated by pressing force due to eccentricity.

For example, Japanese Utility Model Laid-Open No. 48-29257 includes a tightening nut having a concave portion of an appropriate depth on the upper surface portion and a loosening nut having a convex portion that fits into the concave portion. There has been proposed a lock nut whose center is slightly eccentric with respect to the axis of the bolt. According to this Patent Document 1, a shearing force is generated in the locking nut fastened to the bolt in a direction perpendicular to the axial center line of the bolt, and the tightening nut has a direction opposite to the locking nut. It is said that the loosening action can be enhanced by the friction force generated by the contact between the nut and the bolt.

Japanese Patent Laid-Open No. 6-337012 discloses an eccentric double nut in which a tapered convex portion is formed at the upper portion of the lower nut and a tapered concave portion is formed at the lower portion of the upper nut. An eccentric double nut has been proposed in which a flange having a diameter larger than the nut diameter is provided at the lower part of the periphery (Patent Document 2). According to Patent Document 2, as in the invention described in Patent Document 1, the lower nut functions as a fastening nut and the upper nut functions as a loosening nut. Further, when the upper nut is fastened, the fastener comes into contact with a flange provided at the lower periphery of the upper nut, so that the fastener does not interfere with the lower nut.

Japanese Utility Model Publication No. 48-29257 Japanese Patent Laid-Open No. 6-337012

However, in the inventions described in Patent Literature 1 and Patent Literature 2, it is necessary to process the convex portion or the concave portion so as to be eccentric from the axis of the female screw hole, and the convex portion or the concave portion and the female screw hole Cannot be processed at the same time. In other words, there is a problem in that it is necessary to process separately so as to be decentered, which increases labor and processing cost.

Further, in the invention described in Patent Document 2, it is necessary to decenter and separately provide the flange on the upper nut, and there is a problem that the processing cost further increases.

This invention was made in order to solve such a problem, Comprising: It aims at providing the double nut which can suppress manufacturing cost by reducing a manufacturing process while being able to manufacture simply. Yes.

A double nut according to the present invention includes a first nut having a frustoconical convex portion concentric with a female screw hole screwed into a bolt and having a diameter reduced from one end surface of the nut toward the outside, and the bolt A second nut having a frustoconical concave recess that is concentric with a female screw hole to be screwed into the nut and capable of fitting the convex portion into one end surface of the nut. Is formed with an eccentric protrusion formed by projecting a part of the inner peripheral surface of the concave portion inward so that the outer peripheral surface of the convex portion can be pressed when the convex portion is fitted into the concave portion. ing.

Further, as one aspect of the present invention, the eccentric protrusion has a different protruding height along the circumferential direction, and presses the convex portion when the double nut is screwed to the bolt. The protruding height on the front side to be formed may be lower than that on the rear side.

Furthermore, as one aspect of the present invention, the eccentric protrusion is formed to protrude in the concave portion by pressing a part of the outer surface of the second nut inward and plastically deforming, and by the pressing. A guide protrusion may be formed by projecting a part of the outer surface of the second nut outward by plastic deformation.

According to the present invention, the manufacturing process can be simplified, the manufacturing process can be reduced, the manufacturing cost can be suppressed, and the efficiency of the fastening work can be improved.

It is a perspective view showing one embodiment of the first nut in the double nut concerning the present invention. It is a perspective view showing one embodiment of the second nut in the double nut concerning the present invention. It is a bottom view which shows the 2nd nut in this embodiment. FIG. 4 is a vertical sectional view taken along line 4A-4A showing a second nut in the present embodiment. It is a side view which shows the 2nd nut in this embodiment. FIG. 6 is a cross-sectional view taken along line 6A-6A showing the second nut in the present embodiment. It is a perspective view which shows one Embodiment of the double nut fastener which concerns on this invention. It is a bottom view which shows the double nut fastener in this embodiment. It is the double nut fastening method of this embodiment, Comprising: (a) The schematic diagram which shows a double nut insertion process, (b) The schematic diagram which shows the operation | movement which screws a double nut to a volt | bolt, (c) Double nut Schematic diagram showing the temporary fixing step and fastener replacement step, (d) Schematic diagram showing the replacement operation of the fastener replacement step, (e) Schematic diagram showing the fastening operation of the second nut after the fastener replacement, and (F) It is a schematic diagram which shows the state which fastening of the double nut was completed. (A) A longitudinal sectional view showing a state in which the second nut is temporarily fixed in the double nut fastening method of the present embodiment, and (b) a longitudinal section showing a state after the second nut fastening operation in the same method. FIG. It is a perspective view which shows the 1st nut in other embodiment.

Hereinafter, an embodiment of a double nut according to the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a first nut 2 of the double nut 1 of the present embodiment, and FIG. 2 is a perspective view showing a second nut 3.

The double nut 1 of the present embodiment includes a first nut 2 and a second nut 3 as shown in FIGS.

As shown in FIG. 1, the first nut 2 is a hexagonal nut, and has a female screw hole 21 to be screwed with the bolt B, and a convex portion 22 to be inserted into a concave portion 32 of the second nut 3 to be described later. The convex portion 22 is concentric with the female screw hole 21 and is formed in a truncated conical convex shape whose diameter is reduced outward from one end surface of the nut. In addition, the 1st nut 2 in this embodiment functions as a fastening nut fastened with the said volt | bolt B ahead of the 2nd nut 3, and fastened to a fastening target object.

As shown in FIGS. 2 to 6, the second nut 3 is a hexagonal nut of the same type as the first nut 2, and includes a female screw hole 31 to be screwed with the bolt B, and a convex portion 22 of the first nut 2. And a recess 32 to be inserted. The concave portion 32 is concentric with the female screw hole 31 and is formed in a truncated conical concave shape into which the convex portion 22 can be fitted into one end face of the nut.

Further, an eccentric protrusion 33 is formed on the inner peripheral surface of the recess 32. As shown in FIGS. 3, 4 and 6, the eccentric protrusion 33 is formed by projecting a part of the inner peripheral surface of the recess 32 inward. That is, by providing the eccentric protrusion 33, the midpoint between the eccentric protrusion 33 and the inner peripheral surface of the concave portion 32 that is axially symmetric with the eccentric protrusion 33 is eccentric with respect to the axis of the female screw hole 31. It is supposed to be.

Further, the eccentric protrusion 33 in the present embodiment is formed so as to have different protrusion heights along the circumferential direction, and presses the convex portion 22 when the double nut 1 is screwed to the bolt B. The protrusion height of the front side F is formed lower than the rear side R. That is, as shown in FIG. 3, the eccentric protrusion 33 in the present embodiment is formed such that the portion that comes into contact later in the tightening direction is gradually higher than the portion that comes into contact earlier, and is light at the start of tightening. It is tightened by force, and gradually requires a large force as the tightening operation proceeds, and in accordance with this, the pressing force increases and the loosening prevention effect is enhanced.

Further, the eccentric protrusion 33 can be formed by an appropriately selected processing method such as die molding or pressing. In the present embodiment, as shown in FIG. The outer peripheral surface of the recess 32 is pressed to protrude inward and is formed by plastic deformation.

From the above, the second nut 3 is orthogonal to the axis of the bolt B by the eccentric protrusion 33 pressing the outer peripheral surface of the convex portion 22 when the convex portion 22 is fitted into the concave portion 32. A shearing force is applied in the direction to perform, and functions as a locking nut that exhibits a locking action.

Further, a guide projection 34 is formed on the outer peripheral surface of the second nut 3 in the present embodiment. The guide protrusion 34 is used to lock a lower end surface of the double nut fastener 4 described later so that the nut accommodating portion 41 of the double nut fastener 4 does not fit into the first nut 2. 2, 3, 5, and 6, a part of the outer peripheral surface protrudes outward, and the double nut fastener 4 is formed at a height that can be locked. Yes.

Further, the guide protrusion 34 is formed by pressing a part of the outer peripheral surface of the recess 32 at the same time as forming the eccentric protrusion 33 in order to simplify the machining process, and plastic deformation due to the pressing. .

The first nut 2 and the second nut 3 are not limited to hexagonal nuts, and may be polygonal nuts such as square nuts and octagonal nuts, circular nuts, or non-circular nuts, and are loosely secured. The nut provided on the upper side as a nut may be a cap nut, a wing nut, an eye nut, a part having an internal thread, or the like.

Next, the double nut fastener 4 used for fastening the double nut 1 of this embodiment will be described. As shown in FIG. 7, the double nut fastener 4 of the present embodiment is a fastener including a socket such as a box wrench or a socket wrench, and mainly includes a nut housing portion 41 into which the double nut 1 is fitted. And a guide groove 42 for fitting the guide protrusion 34 of the second nut 3 and guiding it to the back side. Note that the double nut fastener 4 is not limited to a socket for a socket wrench, and may have an equivalent configuration at the tip of a spectacle wrench, a screwdriver, or the like.

As shown in FIGS. 7 to 9, the nut accommodating portion 41 is formed in a hexagonal concave shape of the same type as the double nut 1, and is a double nut in which the first nut 2 and the second nut 3 are stacked. It has a shape and depth that can be inserted.

As shown in FIGS. 7 to 9, the guide groove 42 is a groove for fitting the guide projection 34 and guiding it to the back side when the second nut 3 is fitted into the nut accommodating portion 41. On the inner peripheral surface of the nut accommodating portion 41, a linear groove is formed in the vertical direction.

In addition, the fastener used for fastening of the double nut 1 of this embodiment is not limited to the said double nut fastener 4, It may be a spanner, a torque wrench, etc. which are generally marketed. Good.

Next, the operation of each component of the double nut 1 of this embodiment will be described together with a method for fastening the double nut 1 using the double nut fastener 4.

The method of fastening the double nut 1 in the present embodiment includes a double nut fitting step for setting the double nut 1 to the double nut fastener 4 and a double nut temporary fastening for temporarily fastening the double nut 1. A step, an insertion position replacement step of replacing the insertion position of the double nut fastener 4, and a fastening completion step of rotating only the second nut 3 to complete the fastening of the double nut 1.

Hereinafter, each process will be described in detail with reference to the drawings.

The double nut insertion step is a step of inserting the first nut 2 together with the second nut 3 into the nut accommodating portion 41 of the double nut fastener 4. In this embodiment, as shown in FIG. 9A, the guide protrusions 34 of the second nut 3 are fitted and aligned in the guide grooves 42 of the double nut fastener 4, and the guide protrusions 34 are aligned. The second nut 3 and the first nut 2 are inserted into the nut accommodating portion 41 by moving to the back side along the guide groove 42. Here, the convex portion 22 of the first nut 2 is lightly in contact with an eccentric protrusion 33 provided in the concave portion 32 of the second nut 3, and is loosely or slightly fitted in the concave portion 32. However, it is not completely inserted.

The second nut 3 and the first nut 2 may be separately fitted into the nut accommodating portion 41, or the convex portion 22 of the first nut 2 and the concave portion 32 of the second nut 3 are previously overlapped together. It may be inserted in.

In the double nut temporary fixing step, as shown in FIG. 9 (b), the double nut 1 is rotated by the double nut fastener 4 and screwed into the bolt B to be fastened to the fastening object. And the second nut 3 is temporarily fixed. After the completion of the double nut temporary fixing process, as shown in FIG. 10A, the first nut 2 is screwed into the bolt B and is completely fastened to the fastening object.

On the other hand, the second nut 3 is screwed to the bolt B together with the first nut 2, and is fastened to the bolt B halfway along with the fastening of the first nut 2. That is, as shown in FIG. 10A, the convex portion 22 of the first nut 2 only abuts on the eccentric protrusion 33 provided in the concave portion 32 of the second nut 3, and is Thus, no shear force is generated in the orthogonal direction, and the double nut 1 is temporarily fixed.

From the above, in the double nut temporary fixing step, the second nut 3 can be temporarily fixed simultaneously with the operation of completely fastening the first nut 2.

The insertion position replacement step is a step in which the double nut fastener 4 is once removed from the double nut 1 and the position of the double nut fastener 4 is shifted and reinserted. Specifically, as shown in FIG. 9C, the double nut fastener 4 is temporarily removed from the double nut 1 temporarily fixed by the double nut temporary fixing step. Next, as shown in FIG. 9D, the removed double nut fastener 4 is shifted so that the guide groove 42 does not fit the guide projection 34 of the second nut 3, and the double nut fastener 4 is doubled again. By inserting the nut 1, the insertion position is changed.

The fastening completion process is a process of completing the fastening of the double nut 1 by fastening the second nut 3 to prevent the first nut 2 from loosening. As shown in FIG. 9E, the lower end surface of the replaced double nut fastener 4 comes into contact with the guide projection 34 and cannot be inserted deeper than that. Therefore, the double nut fastener 4 is in a state where only the second nut 3 is fitted, and does not interfere with the first nut 2. In this state, by rotating the double nut fastener 4, only the second nut 3 is rotated and fastened to the bolt B.

Further, the second nut 3 in the fastening completion process is rotated along the bolt B by a rotation operation, so that the eccentric protrusion 33 provided in the concave portion 32 rotates while pressing the convex portion 22 of the first nut 2. To do. The convex portion 22 is formed in a truncated cone shape, and the pressure received from the eccentric protrusion 33 increases as the screw advances.

Further, since the portion of the eccentric protrusion 33 that comes into contact later than the portion that comes into contact earlier in the tightening direction is gradually higher, the pressing position changes from the lower protrusion on the front side F to the higher protrusion on the rear side R. By gradually moving, the tightening torque is light at first and gradually increases toward the second half of the tightening, so that the pressing force and the pressing area can be gradually increased. For this reason, the tightening operation becomes smooth as a whole, and the degree of the tightening effect can be felt by the degree of torque transmitted to the double nut fastener 4. Therefore, the operator does not end the tightening operation at a halfway position, and the result is that the tightening is performed firmly to the end, and a high locking effect is surely obtained.

By the above operation, as shown in FIG. 10B, the second nut 3 generates a shearing force in a direction perpendicular to the axis of the bolt B, and the first nut 2 has a second force. A shearing force in the opposite direction to the nut 3 is generated. The female screw hole 21 of the first nut 2 and the female screw hole 31 of the second nut 3 are pressed against the bolt B, and the loosening action is enhanced by the frictional force generated there.

Finally, the fastening operation is completed by removing the double nut fastener 4 from the double nut 1.

According to the double nut 1 of the present embodiment as described above, the following effects can be obtained.
1. Since the female screw holes 21 and 31 and the convex portion 22 or the concave portion 32 are processed without shifting the axis of the double nut 1, the manufacturing is simple and the manufacturing cost is reduced.
2. By providing the eccentric protrusion 33, it is possible to exert a locking effect due to the eccentric action during fastening.
3. The eccentric protrusion 33 and the guide protrusion 34 can be formed by a single pressing operation, and can be easily manufactured.
4). The fastening operation of the nut for fastening and the temporary fastening operation of the nut for loosening can be performed at the same time. After that, the double nut fastener 4 can be easily replaced to complete the fastening. Will improve.
5. Since the height of the eccentric protrusion 33 is changed in the tightening direction, the tightening operation is easy and the degree of tightening can be felt by hand. A stopping effect is obtained.

The double nut according to the present invention is not limited to the above-described embodiment, and can be changed as appropriate.

For example, the first nut 2 and the second nut 3 may be turned upside down, the second nut 3 may be used as a fastening nut, and the first nut 2 having the convex portion 22 may be used as a loosening nut.

In order to enhance the detent effect of the double nut 1, a plurality of grooves 23 may be provided on the side surface of the convex portion 22 of the first nut 2 as shown in FIG.

DESCRIPTION OF SYMBOLS 1 Double nut 2 1st nut 3 2nd nut 4 Double nut fastener 21 Female screw hole 22 Convex part 23 Groove 31 Female screw hole 32 Concave part 33 Eccentric protrusion 34 Guide protrusion 41 Nut accommodating part 42 Guide groove B Bolt F Side R Rear side

Claims

A first nut having a conical convex convex portion that is concentric with a female screw hole to be screwed with the bolt and reduced in diameter outward from one end surface of the nut, and concentric with a female screw hole to be screwed with the bolt. And a double nut composed of a second nut having a concave conical recess capable of fitting the convex portion into one end surface of the nut,
The second nut has an eccentricity in which a part of the inner peripheral surface of the concave portion protrudes inward so that the outer peripheral surface of the convex portion can be pressed when the convex portion is fitted into the concave portion. The projection for eccentricity is formed so as to protrude from the concave portion by plastically deforming by pressing a part of the outer surface of the second nut inward, and the plasticity due to the pressing is formed. A double nut in which a guide protrusion is formed by projecting a part of the outer surface of the second nut outwardly by deformation.
The eccentric protrusions have different projecting heights along the circumferential direction, and the projecting height on the front side that presses the convex portion when the double nut is screwed into the bolt is a rear hand. The double nut according to claim 1, wherein the double nut is formed lower than the side.