JP2021014892A - Double-nut - Google Patents

Abstract

To provide a lock nut which is favorable in work efficiency when screwed to a bolt, low in a cost, and easy in mass production.SOLUTION: A lock nut 1 has a female screw hole 4a screwed with a male screw part 2a of a bolt 2 at a center shaft C1. An annular protrusion 5 extending in a peripheral direction with the center shaft C1 as a center is formed at an opening peripheral edge of the female screw hole 4a at one side. An annular step part 6 extending in the peripheral direction with the center shaft C1 as a center is formed at an opening peripheral edge of the female screw hole 4a at the other side. A center line C2 of the annular protrusion 5 is decentered from the center shaft C1 by a distance D. The annular step part 6 is formed into a shape corresponding to a shape of the annular protrusion 5 so that the annular protrusion 5 can be fit in a direction along the center shaft C1. A center line C3 of the annular step part 6 is decentered from the center shaft C1 by the distance D. By stacking the two nuts 1, and screwing them to the bolt 2, and also by tightening them so that either of the nuts approaches the other, a fall of the two nuts from the bolt 2 is prevented.SELECTED DRAWING: Figure 1

Description

The present invention relates to a locking nut that prevents the bolt from loosening and falling off when the object to be fastened is fastened to the bolt.

Conventionally, various efforts have been considered to prevent a nut screwed into a bolt from loosening from the bolt and falling off. For example, in Patent Document 1, a special shape that can be screwed into a bolt is formed. The first nut and the second nut are disclosed. An annular ridge portion that protrudes in a direction along the central axis of the female screw hole and extends in a circumferential direction around the central axis is provided on the peripheral edge of the opening of the female screw hole in the first nut. The center line of is eccentric from the central axis of the female screw hole in the first nut. On the other hand, on the peripheral edge of the opening of the female screw hole in the second nut, an annular step portion is provided which is recessed in a step shape in the direction along the central axis of the female screw hole and extends in the circumferential direction around the central axis. The stepped portion has a shape corresponding to the shape of the annular ridge portion so that the annular ridge portion can be fitted. The center line of the annular step portion is eccentric from the central axis of the female screw hole in the second nut, and the first and second nuts in a state where the annular protrusion is fitted to the annular step portion and overlapped are bolted. When the first nut is retightened so as to approach the second nut, the eccentric side of the annular ridge portion is pressed against the inner peripheral surface of the annular step portion, and the first and second nuts are strengthened against each other. It is designed to be fixed to.

Jitsukaisho 49-29257

However, the first and second nuts of Patent Document 1 have different shapes from each other, and it is necessary to screw the first and second nuts into the bolts in a fixed order, so that there is a problem that the work efficiency is poor. .. Further, since it is necessary to manufacture the first and second nuts having different shapes, there is a problem that the cost increases.

The present invention has been made in view of these points, and an object of the present invention is to provide a locking nut that has good work efficiency when screwed into a bolt and is easy to manufacture in large quantities at low cost. To do.

In order to achieve the above object, the present invention provides an annular ridge portion on the peripheral edge of the opening on one side of the female screw hole in the locking nut, while the annular step portion has a shape in which the annular ridge portion can be fitted. It is characterized in that the portion is provided on the peripheral edge of the opening on the other side of the female screw hole.

Specifically, it has a female screw hole to be screwed into the male screw part of the bolt on the central axis, and two female screw holes are overlapped and each female screw hole is screwed to the male screw part of the bolt, and one of them is The following solutions have been taken for the locking nuts that are configured to prevent them from falling off the bolts by retightening the other so that they approach each other.

That is, in the first invention, an annular ridge portion that protrudes in the direction along the central axis and extends in the circumferential direction around the central axis is provided on the peripheral edge of the opening on one side of the female screw hole. On the peripheral edge of the opening on the other side of the female screw hole, an annular step portion that is recessed in a step shape in the direction along the central axis and extends in the circumferential direction around the central axis is provided, and the center line of the annular ridge portion is , The annular step portion is eccentric by a distance D from the central axis of the female screw hole, and the annular step portion is the annular ridge portion so that the annular ridge portion can be fitted in the direction along the central axis of the female screw hole. The shape corresponds to the shape of the above, and the center line of the annular step portion is eccentric by the distance D from the central axis of the female screw hole.

In the second invention, in the first invention, the annular ridge portion has a perfect circular shape when viewed from the center line direction, and the annular step portion has a perfect circular shape when viewed from the center line direction. It is characterized by being.

A third invention is characterized in that, in the first or second invention, the eccentric direction of the annular step portion is the same as the eccentric direction of the annular ridge portion.

In the fourth invention, in any one of the first to third inventions, the annular ridge portion extends in the protruding direction of the annular ridge portion in parallel with the central axis of the female screw hole. And a second outer peripheral surface that is continuously provided on the first outer peripheral surface and gradually reduces in diameter toward the protruding end of the annular ridge portion, and the annular step portion is an opening peripheral edge of the annular step portion. A first inner peripheral surface extending parallel to the central axis of the female screw hole and having a shape corresponding to the first outer peripheral surface, and an opening of the annular step portion provided continuously to the first inner peripheral surface. It is provided with a second inner peripheral surface that gradually shrinks in diameter as it moves away from the peripheral edge and has a shape corresponding to the second outer peripheral surface, and when two of the loosening prevention nuts are stacked, an annular protrusion in one of the loosening prevention nuts. It is characterized in that the first outer peripheral surface of the strip portion is configured to be in close contact with the first inner peripheral surface of the annular step portion of the other locking nut.

In the first invention, two locking nuts of the first invention are prepared, and the annular ridges of one nut are overlapped with the annular step portion of the other nut in a state of being fitted to the female of each nut. When the screw hole is screwed into the male screw part of the bolt and then tightened so that the other nut approaches one nut, the eccentric side of the annular ridge portion presses against the inner peripheral surface of the annular step portion. The two nuts will be firmly fixed to each other. In this way, it is possible to prevent both nuts from loosening from the bolt by using two nuts of one shape, and as in Patent Document 1, two nuts of different shapes are prepared and the bolts are arranged in a fixed order. Since there is no need to screw them, the work efficiency when screwing them into bolts is good, and since it is not necessary to manufacture multiple types of nuts, it is possible to keep the manufacture of lock nuts and the cost of parts low. , The nut can be easily manufactured in large quantities.

In the second invention, since it is easy to process the locking nut for forming the annular ridge portion and the annular step portion, the locking nut can be further reduced in cost.

In the third invention, when the annular ridge portion and the annular step portion are formed on the locking nut, the center line of the annular ridge portion and the center line of the annular step portion coincide with each other, which facilitates processing and further. It can be a nut that is easy to manufacture.

In the fourth invention, when the annular ridge portion of one nut is fitted to the annular step portion of the other nut, the second outer peripheral surface of the annular ridge portion of one nut has a so-called tapered shape. The annular ridge portion of one nut is smoothly guided inward of the annular step portion of the other nut while sliding contact with the first inner peripheral surface of the annular step portion of the nut. Therefore, when the two nuts are screwed into the bolts, they can be easily overlapped and workability can be improved. Further, when the annular ridge portion of one nut is fitted to the annular step portion of the other nut, the first outer peripheral surface of the annular ridge portion of one nut is the first inside of the annular step portion of the other nut. Since it is in close contact with the peripheral surface, even if only one nut is gripped, the other nut will not fall off from one nut. Therefore, the work of screwing both nuts into the bolts can be easily performed. Further, the first outer peripheral surface of the annular ridge portion and the first inner peripheral surface of the annular step portion have a shape extending in a direction orthogonal to the eccentric direction of the annular ridge portion and the annular step portion, respectively. Therefore, when the annular ridge portion of one nut and the annular step portion of the other nut are brought into close contact with each other by retightening, the annular ridge portion and the annular step portion become the central axis of the female screw hole of the nut. It becomes difficult to shift in the direction along the line, and both nuts can be fixed more firmly.

It is a front view which showed the partial cross section which shows the state which fastened the object to be fastened between two loosening prevention nuts and bolts which concerns on embodiment of this invention. It is the II arrow view of FIG. It is a front view which showed the partial cross section which shows the state which the two locking nuts which concerns on embodiment of this invention are screwed into a bolt. It is an IV arrow view of FIG. A front view showing a partial cross section showing a state immediately after screwing two locking nuts according to an embodiment of the present invention into a bolt and then retightening one nut so as to approach the other nut. is there. It is a VI arrow view of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is essentially merely an example.

1 and 2 show a state in which the object to be fastened 3 is fastened to and from the bolt 2 using the two locking nuts 1 according to the embodiment of the present invention via a washer 7. The object to be fastened 3 is a thick steel plate, and a through hole 3a through which the male screw portion 2a of the bolt 2 can be inserted is formed.

The lock nut 1 is a so-called hexagon nut, and has a nut body 4 having a hexagonal shape in a plan view.

A female screw hole 4a penetrating along the central axis C1 of the locking nut 1 is formed in the center of the nut body 4, and the female screw hole 4a can be screwed into the male screw portion 2a of the bolt 2. ing.

An annular ridge portion 5 that protrudes in the direction along the central axis C1 and extends in the circumferential direction around the central axis C1 is provided on the peripheral edge of the opening on one side (upper side of FIG. 1) of the female screw hole 4a. The center line C2 of the annular ridge portion 5 is eccentric by a distance D from the central axis C1 of the female screw hole 4a. In addition, in FIG. 1 and FIG. 2, the amount of eccentricity of the annular ridge portion 5 is exaggerated for convenience.

The annular ridge portion 5 is provided continuously on the first outer peripheral surface 5a extending parallel to the central axis C1 of the female screw hole 4a in the projecting direction of the annular ridge portion 5 and the first outer peripheral surface 5a, and is annular. It is provided with a second outer peripheral surface 5b whose diameter gradually decreases toward the protruding end of the ridge portion 5, and has a perfect circular shape when viewed from the center line C2 direction thereof.

On the inner peripheral surface of the annular ridge portion 5, a screw thread continuous with the screw thread of the female screw hole 4a is formed.

On the outer peripheral edge of the opening on the other side (lower side of FIG. 1) of the female screw hole 4a, an annular step portion 6 is provided which is recessed in a step shape in the direction along the central axis C1 and extends in the circumferential direction around the central axis C1. The center line C3 of the annular step portion 6 is eccentric by a distance D from the central axis C1 of the female screw hole 4a in the same direction as the eccentric direction of the annular ridge portion 5. In addition, in FIG. 1 and FIG. 2, the amount of eccentricity of the annular step portion 6 is exaggerated for convenience.

The annular step portion 6 has a perfect circular shape when viewed from the center line C3 direction, extends parallel to the central axis C1 of the female screw hole 4a from the opening peripheral edge of the annular step portion 6, and corresponds to the first outer peripheral surface 5a. The first inner peripheral surface 6a and the first inner peripheral surface 6a are continuously provided, and the diameter gradually decreases as the distance from the opening peripheral edge of the annular step portion 6 increases, and the diameter corresponds to the second outer peripheral surface 5b. It is provided with a second inner peripheral surface 6b having a shape to be formed.

That is, the annular step portion 6 has a shape corresponding to the shape of the annular ridge portion 5 so that the annular ridge portion 5 can be fitted in the direction along the central axis C1 of the female screw hole 4a.

Next, the method of using the locking nut 1 according to the embodiment of the present invention will be described in detail.

First, as shown in FIGS. 3 and 4, two locking nuts 1 are prepared, and one annular ridge portion 5 of the two prepared locking nuts 1 is fitted to the other annular step portion 6. After overlapping both nuts 1, each female screw hole 4a is screwed into the male screw portion 2a of the bolt 2. When the annular ridge portion 5 of one nut 1 is fitted to the annular step portion 6 of the other nut 1, the second outer peripheral surface 5b of the annular ridge portion 5 of one nut 1 forms a so-called tapered shape. The annular ridge portion 5 of one nut 1 is smoothly guided inward of the annular step portion 6 of the other nut 1 while sliding contact with the first inner peripheral surface 6a of the annular step portion 6 of the other nut 1. Therefore, when the two nuts 1 are screwed into the bolt 2, they can be easily overlapped with each other, and workability can be improved. Further, when the annular ridge portion 5 of one nut 1 is fitted to the annular step portion 6 of the other nut 1, the first outer peripheral surface 5a of the annular ridge portion 5 of one nut 1 becomes the other nut 1. Since it is in close contact with the first inner peripheral surface 6a of the annular step portion 6 in the above, even if only one nut 1 is gripped, the other nut 1 does not fall off from the one nut 1. Therefore, the work of screwing both nuts 1 into the bolt 2 can be easily performed.

After that, retightening is performed so that the other nut 1 approaches the one nut 1. Specifically, as shown in FIGS. 5 and 6, the other nut 1 is rotated clockwise by about 60 ° with respect to one nut 1. Then, the eccentric side of the annular ridge portion 5 of one nut 1 is pressed against the inner peripheral surface of the annular step portion 6 of the other nut 1, and the two nuts 1 are firmly fixed to each other. In other words, the first outer peripheral surface 5a of the annular ridge portion 5 in one nut 1 and the first inner peripheral surface 6a of the annular step portion 6 in the other nut 1 are the annular ridge portion 5 and the annular step portion 6. Since each has a shape extending in a direction orthogonal to the eccentric direction, the annular ridge portion 5 of one nut 1 and the annular step portion 6 of the other nut 1 are brought into close contact with each other by retightening. At this time, the annular ridge portion 5 and the annular step portion 6 are less likely to be displaced in the direction along the central axis C1 in the female screw hole 4a of the nut 1, and both nuts 1 are more firmly fixed by this structure. ..

As described above, according to the embodiment of the present invention, it is possible to prevent both nuts 1 from loosening from the bolt 2 by using two nuts 1 having one shape, and two different shapes as in Patent Document 1. Since it is not necessary to prepare nuts and screw them into the bolts in a fixed order, the work efficiency when screwing them into the bolts 2 is good, and since it is not necessary to manufacture multiple types of nuts 1, it is loose. The production of the stop nut 1 and the cost of parts can be kept low, and the nut 1 can be easily manufactured in large quantities.

Further, since the annular ridge portion 5 and the annular step portion 6 each have a perfect circular shape when viewed in the direction of the center lines C2 and C3, the annular ridge portion 5 and the annular step portion 6 are formed on the locking nut 1. It is easy to process when doing. Therefore, the lock nut 1 can be used at a lower cost.

Further, since the eccentric direction of the annular step portion 6 in the locking nut 1 is the same as the eccentric direction of the annular ridge portion 5, when the annular ridge portion 5 and the annular step portion 6 are formed in the locking nut 1. , The center line C2 of the annular ridge portion 5 and the center line C3 of the annular step portion 6 come to coincide with each other. Therefore, the lock nut 1 can be easily processed when it is manufactured, and the nut can be further easily manufactured.

In the embodiment of the present invention, the structure of the present invention is applied to a so-called hexagon nut, but the structure of the present invention can also be applied to other types of nuts.

The present invention is suitable for a locking nut that prevents the bolt from loosening and falling off when the object to be fastened is fastened to the bolt.

1 Loosening prevention nut 2 Bolt 2a Male screw part 3 Attached body 4a Female screw hole 5 Circular ridge 5a 1st outer peripheral surface 5b 2nd outer peripheral surface 6 Ring stepped part 6a 1st inner peripheral surface 6b 2nd inner peripheral surface C1 Central axis of locking nut C2 Center line of annular ridge C3 Center line of annular step D Eccentric distance

The present invention relates to a double nut in which two nuts of the same shape are stacked to prevent the bolt from loosening and falling off when the object to be fastened is fastened to the bolt.

Conventionally, various efforts have been considered to prevent a nut screwed into a bolt from loosening from the bolt and falling off. For example, in Patent Document 1, a special shape that can be screwed into a bolt is formed. The first nut and the second nut are disclosed. An annular ridge portion that protrudes in a direction along the central axis of the female screw hole and extends in a circumferential direction around the central axis is provided on the peripheral edge of the opening of the female screw hole in the first nut. The center line of is eccentric from the central axis of the female screw hole in the first nut. On the other hand, on the peripheral edge of the opening of the female screw hole in the second nut, an annular step portion is provided which is recessed in a step shape in the direction along the central axis of the female screw hole and extends in the circumferential direction around the central axis. The stepped portion has a shape corresponding to the shape of the annular ridge portion so that the annular ridge portion can be fitted. The center line of the annular step portion is eccentric from the central axis of the female screw hole in the second nut, and the first and second nuts in a state where the annular protrusion is fitted to the annular step portion and overlapped are bolted. When the first nut is retightened so as to approach the second nut, the eccentric side of the annular ridge portion is pressed against the inner peripheral surface of the annular step portion, and the first and second nuts are strengthened against each other. It is designed to be fixed to.

Jitsukaisho 48-29257

However, the first and second nuts of Patent Document 1 have different shapes from each other, and it is necessary to screw the first and second nuts into the bolts in a fixed order, so that there is a problem that the work efficiency is poor. .. Further, since it is necessary to manufacture the first and second nuts having different shapes, there is a problem that the cost increases.

The present invention has been made in view of these points, and an object of the present invention is to provide a locking nut that has good work efficiency when screwed into a bolt and is easy to manufacture in large quantities at low cost. To do.

In order to achieve the above object, the present invention provides an annular ridge portion on the peripheral edge of the opening on one side of the female screw hole in the locking nut, while the annular step portion has a shape in which the annular ridge portion can be fitted. It is characterized in that the portion is provided on the peripheral edge of the opening on the other side of the female screw hole.

Specifically, it has a female screw hole to be screwed into the male screw part of the bolt on the central axis, and two female screw holes are overlapped and each female screw hole is screwed to the male screw part of the bolt, and one of them is The following solution was taken in a double nut in which two nuts of the same shape are stacked so as to prevent the bolt from falling off by tightening the other so as to approach each other.

That is, in the first invention, an annular ridge portion that protrudes in the direction along the central axis and extends in the circumferential direction around the central axis is provided on the peripheral edge of the opening on one side of the female screw hole. On the peripheral edge of the opening on the other side of the female screw hole, an annular step portion that is recessed in a step shape in the direction along the central axis and extends in the circumferential direction around the central axis is provided, and the center line of the annular ridge portion is , The annular step portion is eccentric by a distance D from the central axis of the female screw hole, and the annular step portion is the annular ridge portion so that the annular ridge portion can be fitted in the direction along the central axis of the female screw hole. The shape corresponds to the shape of the above, and the center line of the annular step portion is eccentric by the distance D from the central axis of the female screw hole.

In the second invention, in the first invention, the annular ridge portion has a perfect circular shape when viewed from the center line direction, and the annular step portion has a perfect circular shape when viewed from the center line direction. It is characterized by being.

A third invention is characterized in that, in the first or second invention, the eccentric direction of the annular step portion is the same as the eccentric direction of the annular ridge portion.

In the fourth invention, in any one of the first to third inventions, the annular ridge portion extends in the protruding direction of the annular ridge portion in parallel with the central axis of the female screw hole. And a second outer peripheral surface that is continuously provided on the first outer peripheral surface and gradually reduces in diameter toward the protruding end of the annular ridge portion, and the annular step portion is an opening peripheral edge of the annular step portion. A first inner peripheral surface extending parallel to the central axis of the female screw hole and having a shape corresponding to the first outer peripheral surface, and an opening of the annular step portion provided continuously to the first inner peripheral surface. gradually reduced in diameter with distance from the periphery, and, above a second inner peripheral surface forming a corresponding shape to the second outer peripheral surface, when the upper quinic Tsu bets two superposed, circular in one nuts wherein the first outer peripheral surface of the protruding portion is configured to contact the first inner peripheral surface of the annular step portion of the other nuts.

In the first invention, two locking nuts of the first invention are prepared, and the annular ridges of one nut are overlapped with the annular step portion of the other nut in a state of being fitted to the female of each nut. When the screw hole is screwed into the male screw part of the bolt and then tightened so that the other nut approaches one nut, the eccentric side of the annular ridge portion presses against the inner peripheral surface of the annular step portion. The two nuts will be firmly fixed to each other. In this way, it is possible to prevent both nuts from loosening from the bolt by using two nuts of one shape, and as in Patent Document 1, two nuts of different shapes are prepared and the bolts are arranged in a fixed order. Since there is no need to screw them, the work efficiency when screwing them into bolts is good, and since it is not necessary to manufacture multiple types of nuts, it is possible to keep the manufacture of lock nuts and the cost of parts low. , The nut can be easily manufactured in large quantities.

In the second invention, since it is easy to process the locking nut for forming the annular ridge portion and the annular step portion, the locking nut can be further reduced in cost.

In the third invention, when the annular ridge portion and the annular step portion are formed on the locking nut, the center line of the annular ridge portion and the center line of the annular step portion coincide with each other, which facilitates processing and further. It can be a nut that is easy to manufacture.

In the fourth invention, when the annular ridge portion of one nut is fitted to the annular step portion of the other nut, the second outer peripheral surface of the annular ridge portion of one nut has a so-called tapered shape. The annular ridge portion of one nut is smoothly guided inward of the annular step portion of the other nut while sliding contact with the first inner peripheral surface of the annular step portion of the nut. Therefore, when the two nuts are screwed into the bolts, they can be easily overlapped and workability can be improved. Further, when the annular ridge portion of one nut is fitted to the annular step portion of the other nut, the first outer peripheral surface of the annular ridge portion of one nut is the first inside of the annular step portion of the other nut. Since it is in close contact with the peripheral surface, even if only one nut is gripped, the other nut will not fall off from one nut. Therefore, the work of screwing both nuts into the bolts can be easily performed. Further, the first outer peripheral surface of the annular ridge portion and the first inner peripheral surface of the annular step portion have a shape extending in a direction orthogonal to the eccentric direction of the annular ridge portion and the annular step portion, respectively. Therefore, when the annular ridge portion of one nut and the annular step portion of the other nut are brought into close contact with each other by retightening, the annular ridge portion and the annular step portion become the central axis of the female screw hole of the nut. It becomes difficult to shift in the direction along the line, and both nuts can be fixed more firmly.

It is a front view which showed the partial cross section which shows the state which fastened the object to be fastened between two loosening prevention nuts and bolts which concerns on embodiment of this invention. It is the II arrow view of FIG. It is a front view which showed the partial cross section which shows the state which the two locking nuts which concerns on embodiment of this invention are screwed into a bolt. It is an IV arrow view of FIG. A front view showing a partial cross section showing a state immediately after screwing two locking nuts according to an embodiment of the present invention into a bolt and then retightening one nut so as to approach the other nut. is there. It is a VI arrow view of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is essentially merely an example.

1 and 2 show a state in which the object to be fastened 3 is fastened to and from the bolt 2 using the two locking nuts 1 according to the embodiment of the present invention via a washer 7. The object to be fastened 3 is a thick steel plate, and a through hole 3a through which the male screw portion 2a of the bolt 2 can be inserted is formed.

The lock nut 1 is a so-called hexagon nut, and has a nut body 4 having a hexagonal shape in a plan view.

A female screw hole 4a penetrating along the central axis C1 of the locking nut 1 is formed in the center of the nut body 4, and the female screw hole 4a can be screwed into the male screw portion 2a of the bolt 2. ing.

An annular ridge portion 5 that protrudes in the direction along the central axis C1 and extends in the circumferential direction around the central axis C1 is provided on the peripheral edge of the opening on one side (upper side of FIG. 1) of the female screw hole 4a. The center line C2 of the annular ridge portion 5 is eccentric by a distance D from the central axis C1 of the female screw hole 4a. In addition, in FIG. 1 and FIG. 2, the amount of eccentricity of the annular ridge portion 5 is exaggerated for convenience.

The annular ridge portion 5 is provided continuously on the first outer peripheral surface 5a extending parallel to the central axis C1 of the female screw hole 4a in the projecting direction of the annular ridge portion 5 and the first outer peripheral surface 5a, and is annular. It is provided with a second outer peripheral surface 5b whose diameter gradually decreases toward the protruding end of the ridge portion 5, and has a perfect circular shape when viewed from the center line C2 direction thereof.

On the inner peripheral surface of the annular ridge portion 5, a screw thread continuous with the screw thread of the female screw hole 4a is formed.

On the outer peripheral edge of the opening on the other side (lower side of FIG. 1) of the female screw hole 4a, an annular step portion 6 is provided which is recessed in a step shape in the direction along the central axis C1 and extends in the circumferential direction around the central axis C1. The center line C3 of the annular step portion 6 is eccentric by a distance D from the central axis C1 of the female screw hole 4a in the same direction as the eccentric direction of the annular ridge portion 5. In addition, in FIG. 1 and FIG. 2, the amount of eccentricity of the annular step portion 6 is exaggerated for convenience.

The annular step portion 6 has a perfect circular shape when viewed from the center line C3 direction, extends parallel to the central axis C1 of the female screw hole 4a from the opening peripheral edge of the annular step portion 6, and corresponds to the first outer peripheral surface 5a. The first inner peripheral surface 6a and the first inner peripheral surface 6a are continuously provided, and the diameter gradually decreases as the distance from the opening peripheral edge of the annular step portion 6 increases, and the diameter corresponds to the second outer peripheral surface 5b. It is provided with a second inner peripheral surface 6b having a shape to be formed.

That is, the annular step portion 6 has a shape corresponding to the shape of the annular ridge portion 5 so that the annular ridge portion 5 can be fitted in the direction along the central axis C1 of the female screw hole 4a.

Next, the method of using the locking nut 1 according to the embodiment of the present invention will be described in detail.

First, as shown in FIGS. 3 and 4, two locking nuts 1 are prepared, and one annular ridge portion 5 of the two prepared locking nuts 1 is fitted to the other annular step portion 6. After overlapping both nuts 1, each female screw hole 4a is screwed into the male screw portion 2a of the bolt 2. When the annular ridge portion 5 of one nut 1 is fitted to the annular step portion 6 of the other nut 1, the second outer peripheral surface 5b of the annular ridge portion 5 of one nut 1 forms a so-called tapered shape. The annular ridge portion 5 of one nut 1 is smoothly guided inward of the annular step portion 6 of the other nut 1 while sliding contact with the first inner peripheral surface 6a of the annular step portion 6 of the other nut 1. Therefore, when the two nuts 1 are screwed into the bolt 2, they can be easily overlapped with each other, and workability can be improved. Further, when the annular ridge portion 5 of one nut 1 is fitted to the annular step portion 6 of the other nut 1, the first outer peripheral surface 5a of the annular ridge portion 5 of one nut 1 becomes the other nut 1. Since it is in close contact with the first inner peripheral surface 6a of the annular step portion 6 in the above, even if only one nut 1 is gripped, the other nut 1 does not fall off from the one nut 1. Therefore, the work of screwing both nuts 1 into the bolt 2 can be easily performed.

After that, retightening is performed so that the other nut 1 approaches the one nut 1. Specifically, as shown in FIGS. 5 and 6, the other nut 1 is rotated clockwise by about 60 ° with respect to one nut 1. Then, the eccentric side of the annular ridge portion 5 of one nut 1 is pressed against the inner peripheral surface of the annular step portion 6 of the other nut 1, and the two nuts 1 are firmly fixed to each other. In other words, the first outer peripheral surface 5a of the annular ridge portion 5 in one nut 1 and the first inner peripheral surface 6a of the annular step portion 6 in the other nut 1 are the annular ridge portion 5 and the annular step portion 6. Since each has a shape extending in a direction orthogonal to the eccentric direction, the annular ridge portion 5 of one nut 1 and the annular step portion 6 of the other nut 1 are brought into close contact with each other by retightening. At this time, the annular ridge portion 5 and the annular step portion 6 are less likely to be displaced in the direction along the central axis C1 in the female screw hole 4a of the nut 1, and both nuts 1 are more firmly fixed by this structure. ..

As described above, according to the embodiment of the present invention, it is possible to prevent both nuts 1 from loosening from the bolt 2 by using two nuts 1 having one shape, and two different shapes as in Patent Document 1. Since it is not necessary to prepare nuts and screw them into the bolts in a fixed order, the work efficiency when screwing them into the bolts 2 is good, and since it is not necessary to manufacture multiple types of nuts 1, it is loose. The production of the stop nut 1 and the cost of parts can be kept low, and the nut 1 can be easily manufactured in large quantities.

Further, since the annular ridge portion 5 and the annular step portion 6 each have a perfect circular shape when viewed in the direction of the center lines C2 and C3, the annular ridge portion 5 and the annular step portion 6 are formed on the locking nut 1. It is easy to process when doing. Therefore, the lock nut 1 can be used at a lower cost.

Further, since the eccentric direction of the annular step portion 6 in the locking nut 1 is the same as the eccentric direction of the annular ridge portion 5, when the annular ridge portion 5 and the annular step portion 6 are formed in the locking nut 1. , The center line C2 of the annular ridge portion 5 and the center line C3 of the annular step portion 6 come to coincide with each other. Therefore, the lock nut 1 can be easily processed when it is manufactured, and the nut can be further easily manufactured.

In the embodiment of the present invention, the structure of the present invention is applied to a so-called hexagon nut, but the structure of the present invention can also be applied to other types of nuts.

The present invention is suitable for a double nut in which two nuts of the same shape are stacked to prevent the bolt from loosening and falling off when the object to be fastened is fastened to the bolt.

1 Loosening prevention nut 2 Bolt 2a Male screw part 3 Attached body 4a Female screw hole 5 Circular ridge 5a 1st outer peripheral surface 5b 2nd outer peripheral surface 6 Ring stepped part 6a 1st inner peripheral surface 6b 2nd inner peripheral surface C1 Central axis of locking nut C2 Center line of annular ridge C3 Center line of annular step D Eccentric distance

Claims (4)

It has a female screw hole to be screwed into the male screw part of the bolt on the central axis, and two are overlapped so that each female screw hole is screwed into the male screw part of the bolt and the other is brought closer to one. It is a locking nut configured to prevent it from falling off from the bolt by tightening it.
An annular ridge portion that protrudes in the direction along the central axis and extends in the circumferential direction around the central axis is provided on the peripheral edge of the opening on one side of the female screw hole.
On the peripheral edge of the opening on the other side of the female screw hole, an annular step portion is provided which is recessed in a step shape in the direction along the central axis and extends in the circumferential direction around the central axis.
The center line of the annular ridge portion is eccentric by a distance D from the central axis of the female screw hole.
The annular step portion has a shape corresponding to the shape of the annular ridge portion so that the annular ridge portion can be fitted in the direction along the central axis of the female screw hole. The center line is a locking nut characterized in that it is eccentric by the distance D from the central axis of the female screw hole. In the locking nut according to claim 1,
The annular ridge has a perfect circular shape when viewed from the center line direction.
The annular step portion is a locking nut characterized in that it has a perfect circular shape when viewed from the center line direction. In the locking nut according to claim 1 or 2.
A locking nut characterized in that the eccentric direction of the annular step portion is the same as the eccentric direction of the annular ridge portion. In the locking nut according to any one of claims 1 to 3,
The annular ridge portion is provided continuously on the first outer peripheral surface extending parallel to the central axis of the female screw hole in the protruding direction of the annular ridge portion, and the annular ridge portion. With a second outer peripheral surface that gradually shrinks in diameter toward the protruding end of the
The annular step portion extends from the opening peripheral edge of the annular step portion in parallel with the central axis of the female screw hole, and has a shape corresponding to the first outer peripheral surface, and the first inner peripheral surface. A second inner peripheral surface having a shape corresponding to the second outer peripheral surface and gradually reducing in diameter as the distance from the opening peripheral edge of the annular step portion is provided.
When two of the above locking nuts are stacked, the first outer peripheral surface of the annular ridge portion of one locking nut is configured to be in close contact with the first inner peripheral surface of the annular step portion of the other locking nut. A lock nut that is characterized by that.