Set nut and double nut

Abstract

To provide a set nut of a lock nut which is easy in construction but in which centroids are not displaced even if two overlapped nuts are fitted, and a double nut.SOLUTION: A set nut consists of a recessed nut 1B and a projected nut 1A. In the projected nut 1A, an annular protrusion part 5 protruding in a direction along a central axis C is provided at an opening peripheral edge at one side of a female screw hole 4a. In the annular protrusion part 5, a rugged inclined plane which is ruggedness formed from an inclined plane is provided on a tip end face 5b in a protrusion direction. In the recessed nut 1B, an annular step part 6 which is recessed in a step shape in a direction along the central axis C is provided at an opening peripheral edge at the other side of the female screw hole 4a. In the annular step part 6, a rugged inclined plane is provided on a ceiling plane 6b. A plurality of inclined planes provided on the ceiling plane 6b is formed correspondingly to a plurality of inclined planes provided on the tip end face 5b.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a set nut and a double nut that prevent loosening and falling off from a bolt when fastening a fastened object to the bolt.

Background Art

[0002] Generally, in order to firmly fix a structure or a mechanical member, welding or bolt and nut tightening is performed. However, when welding is performed for fixing, there is a problem that it cannot be disassembled and repaired. In addition, when bolt and nut tightening is performed for fixing, although it can be disassembled and repaired, there is a risk that the nut may loosen due to vibration during operation, causing problems in mechanical members and the like. In order to eliminate these causes, various bolts and nuts for preventing loosening have been devised.

[0003] A typical anti-loosening nut currently widely used is a set nut composed of a first nut and a second nut. A concave surface and a convex surface are inserted into the first nut and the second nut, and the eccentricity of the axis of the convex surface is used to apply a load to the side surface of the concave surface to prevent the nut from loosening (see, for example, Patent Document 1).

[0004] In this type of anti-loosening nut, a large amount of load (pressure) may be applied to the side wall of the concave nut, causing deformation of the side wall. A washer-shaped circle is attached to the lower part of the concave nut for reinforcement. This has been widely used as it is.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the lock nut disclosed in Patent Document 1, since a load is applied to the concave side surface by using shaft eccentricity, there is a problem that the centers of gravity of the first nut and the second nut are displaced. When such a lock nut is rotated at high speed about the axis, a load is applied to the concave side surface, which inhibits the smooth rotation of the lock nut and causes vibration. Further, in the lock nut disclosed in Patent Document 1, since the first nut and the second nut are eccentrically fitted by applying a load to the concave side surface by using shaft eccentricity, there is also a problem that a gap is generated in the eccentric direction. For this reason, there is a risk that dust and moisture will enter the gap of such a lock nut, and depending on the material of the lock nut, it may lead to corrosion.

[0007] Therefore, the inventor has conducted long-term studies and research on a lock nut that is not inferior to the lock nut disclosed in Patent Document 1, and has arrived at the present invention.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide a set nut and a double nut that are easy to construct and are lock nuts in which the centers of gravity do not shift even when two stacked nuts are fitted.

Means for Solving the Problems

[0009] In order to achieve the above object, in the present invention, a set nut is composed of a lower nut and an upper nut having female screw holes that are screwed into the male screw portion of a bolt along a central axis, and the lower nut and the upper nut are stacked and their respective female screw holes are screwed into the male screw portion of the bolt, respectively, so as to prevent the bolt from falling off. The following solution means have been taken.

[0010] That is, in the lower nut, an annular protrusion is provided at the opening peripheral edge on one side of the female screw hole, which protrudes in the direction along the central axis and extends in the circumferential direction around the central axis. In the annular protrusion, an uneven inclined surface, which is an unevenness formed by an inclined surface, is provided on the tip surface, which is the surface of the protruding part. In the upper nut, an annular step is provided at the opening peripheral edge on the other side of the female screw hole, which is recessed in a stepped manner in the direction along the central axis and extends in the circumferential direction around the central axis. In the annular step, an uneven inclined surface is provided on the ceiling surface, which is the surface of the part that is recessed in the stepped manner and is connected to the female screw hole. The annular step has a shape corresponding to the shape of the annular protrusion so that the annular protrusion can be fitted in the direction along the central axis, and the uneven inclined surface provided on the ceiling surface has a shape corresponding to the uneven inclined surface provided on the tip surface.

[0011] Further, in order to achieve the above object, in a double nut formed by stacking two nuts of the same shape having a female screw hole that is screwed onto the male screw part of a bolt along the central axis and screwing each female screw hole onto the male screw part of the bolt to prevent the bolt from falling off, the following solution means is adopted.

[0012] That is, an annular protrusion is provided at the opening peripheral edge on one side of the female screw hole, which protrudes in the direction along the central axis and extends in the circumferential direction around the central axis. In the annular protrusion, an uneven inclined surface, which is an unevenness formed by an inclined surface, is provided on the tip surface, which is the surface of the protruding part. An annular step is provided at the opening peripheral edge on the other side of the female screw hole, which is recessed in a stepped manner in the direction along the central axis and extends in the circumferential direction around the central axis. In the annular step, an uneven inclined surface is provided on the ceiling surface, which is the surface of the recessed stepped part and is connected to the female screw hole. The annular step has a shape corresponding to the shape of the annular protrusion so that the annular protrusion can be fitted in the direction along the central axis, and the uneven inclined surface provided on the ceiling surface has a shape corresponding to the uneven inclined surface provided on the tip surface.

Effect of the Invention

[0013] According to the present invention, when preparing a set nut composed of a lower nut and an upper nut, with the tip surface of the annular ridge portion of the lower nut fitted into the annular stepped portion of the upper nut, the female screw holes of the respective nuts are screwed onto the male screw portion of the bolt, so that the tip surfaces of the lower nut and the upper nut, that is, the mutually concave and convex inclined surfaces, slide upward and are fixed near the apex by the mutually concave and convex inclined surfaces.

[0014] Also, when preparing a double nut composed of two nuts of the same shape, with the tip surface of the annular ridge portion of one nut fitted into the annular stepped portion of the other nut, the female screw holes of the respective nuts are screwed onto the male screw portion of the bolt, so that the tip surfaces of the lower nut and the upper nut, that is, the mutually facing concave and convex inclined surfaces, slide upward and are fixed near the apex by the mutually concave and convex inclined surfaces.

[0015] In this way, the set nut and the double nut are fixed by applying an upward and downward load (pressure) through the fastened object and the bolt, and since it is not fixed by eccentric fitting, no load is applied to the left and right (sides).

[0016] As a result, in the set nut and the double nut, even in the fixed state, the centers of gravity of the two nuts coincide (the centers of gravity do not shift). Also, even in the fixed state, no gap is generated between the two nuts.

[0017] Furthermore, in the set nut and the double nut, it is possible to fix simply by screwing the female screw holes of the respective nuts onto the male screw portion of the bolt after sandwiching the fastened object via the bolt with the tip surface of the annular ridge portion of the lower nut or one nut fitted into the annular stepped portion of the upper nut or the other nut, so that construction can be easily performed.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Mode for Carrying Out the Invention

[0019] Hereinafter, with reference to the accompanying drawings, the set nut and double nut according to the embodiments of the present invention will be described in detail. However, the following description of the preferred embodiments is merely illustrative in nature. That is, the following embodiments do not limit the invention according to each claim. Also, in the following embodiments, the scales, dimensions, etc. of each component may be exaggerated or minimized, and some components may be omitted.

[0020] Also, the following drawings are schematic, and for the convenience of explanation, some components or the like may be omitted. Also, the same reference numerals may be given to the common parts of one or more embodiments, and the description may be omitted. [Embodiment 1]

[0021] FIG. 1 is a perspective view of the concave nut 1B according to Embodiment 1 of the present invention as viewed from below. FIG. 2 is a perspective view of the convex nut 1A according to Embodiment 1 of the present invention as viewed from above. FIG. 3 is a front view of the concave nut 1B shown in FIG. 1, and FIG. 4 is a bottom view of the concave nut 1B shown in FIG. 1. FIG. 5 is a front view of the convex nut 1A shown in FIG. 2, and FIG. 6 is a plan view of the convex nut 1A shown in FIG. 2.

[0022] The concave nut 1B and the convex nut 1A are also referred to as an upper nut and a lower nut, respectively, and function as a set nut when used by being stacked in this order. Incidentally, the convex nut 1A can also be referred to as an A nut, in addition to being referred to as a lower nut. The concave nut 1B can also be referred to as a B nut, in addition to being referred to as an upper nut.

[0023] The convex nut 1A and the concave nut 1B are so-called hexagonal nuts and have a nut body 4 that is hexagonal in plan view. The convex nut 1A and the concave nut 1B have a female screw hole 4a that penetrates along the central axis C at the center of the nut body 4, and the female screw hole 4a can be screwed into the male screw portion 2a of a bolt 2 described later.

[0024] In the case of the convex nut 1A which is the lower nut, an annular protrusion 5 is provided on the opening peripheral edge on one side (the upper side in FIGS. 2 and 5) of the female screw hole 4a, protruding in the direction along the central axis C and extending circumferentially around the central axis C.

[0025] As shown in FIGS. 2 and 5 for example, the annular protrusion 5 includes an outer peripheral surface 5a extending parallel to the central axis C of the female screw hole 4a in the protruding direction of the annular protrusion 5, and a tip surface 5b which is the surface at the tip in the protruding direction (the upward direction in FIGS. 2 and 5). The outer periphery and the inner periphery of the annular protrusion 5 are circular when viewed from the direction of the central axis C as shown in FIG. 6 for example. In addition, screw threads continuous with the screw threads of the female screw hole 4a are formed on the inner peripheral surface of the annular protrusion 5.

[0026] The tip surface 5b is provided so as to be continuous with the outer peripheral surface 5a and to extend circumferentially around the central axis C. As shown in FIG. 2 for example, the tip surface 5b is provided with irregularities (irregular inclined surfaces) formed by a plurality of inclined surfaces. In addition, the concave portions of the irregular inclined surfaces correspond to a shape in which a part of the upper portion of the outer peripheral surface 5a is shaved as shown in FIG. 5, but can be obtained by providing an inclined surface having a gentle decreasing inclination. Thus, the concave portions of the irregular inclined surfaces are concave portions formed by inclined surfaces having a decreasing inclination. On the contrary, the convex portions of the irregular inclined surfaces are convex portions formed by inclined surfaces having an increasing inclination.

[0027] In the example shown in FIG. 6, inclined surfaces 51 to 56 are provided on the tip surface 5b, and the vicinity of the boundary (near the boundary line in FIG. 6) continuous with the inclined surface 51 and the inclined surface 52 is a concave portion for example, and the vicinity of the boundary (near the boundary line in FIG. 6) continuous with the inclined surface 51 and the inclined surface 56 is a convex portion for example. Thus, the vicinity of the boundary line in FIG. 6 is a convex or concave portion of the irregular inclined surface.

[0028] The number of inclined surfaces and the number of concavities and convexities described with reference to FIG. 6 are merely examples. As long as the concavities and convexities are provided so as to appear alternately, the number thereof is not limited, but a suitable number is limited according to the size of the male nut 1A. For example, when the size of the male nut 1A is small, the number thereof is small, and when the size of the male nut 1A is large, the number can be increased. Further, as long as convex or concave portions of the concavity-convex inclined surface can be provided by increasing or decreasing the inclination of the inclined surface, the inclination does not have to be a constant angle.

[0029] Further, in the female nut 1B which is the upper nut, an annular stepped portion 6 which is recessed in a stepped manner in the direction along the central axis C and extends in the circumferential direction about the central axis C is provided at the opening peripheral edge on the other side (the lower side in FIGS. 1 and 3) of the female screw hole 4a.

[0030] The annular stepped 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 C. Specifically, as shown in FIGS. 1 and 3, for example, the annular stepped portion 6 extends parallel to the central axis C of the female screw hole 4a in the recessed direction (the upward direction in FIGS. 1 and 3) of the annular stepped portion 6, and has an inner peripheral surface 6a having a shape corresponding to the outer peripheral surface 5a, and a ceiling surface 6b which is a stepped portion of the annular stepped portion 6 where it is recessed and is a surface of a portion connected to the female screw hole 4a. The outer periphery and the inner periphery of the annular stepped portion 6 are circular when viewed from the direction of the central axis C as shown in FIG. 4, for example.

[0031] The ceiling surface 6b is provided so as to be continuous with the inner peripheral surface 6a and to extend in the circumferential direction about the central axis C. Further, as shown in FIGS. 1 and 3, for example, concavities and convexities (concavity-convex inclined surfaces) formed by inclined surfaces are provided on the ceiling surface 6b. The concavity-convex inclined surface provided on the ceiling surface 6b has a shape corresponding to the concavity-convex inclined surface provided on the tip surface 5b.

[0032] The convex portion of the uneven inclined surface provided on the ceiling surface 6b corresponds to a shape as if a part of the upper portion of the inner peripheral surface 6a is shaved off as shown in FIG. 3, but it can be obtained by providing an inclined surface having a gently decreasing inclination. Further, the convex portion of the uneven inclined surface provided on the ceiling surface 6b corresponds to the concave portion of the uneven inclined surface provided on the tip surface 5b. That is, for example, as shown in FIG. 3, the convex portion of the uneven inclined surface is formed by an inclined surface having a decreasing inclination, and the concave portion of the uneven inclined surface is formed by an inclined surface having an increasing inclination.

[0033] In the example shown in FIG. 4, inclined surfaces 61 to 66 are provided on the ceiling surface 6b. Near the boundary (near the boundary line in FIG. 4) continuous with the inclined surface 61 and the inclined surface 62 is, for example, a concave portion, and near the boundary (near the boundary line in FIG. 4) continuous with the inclined surface 61 and the inclined surface 66 is a convex portion. Thus, near the boundary line in FIG. 4 is a convex portion or a concave portion of the uneven inclined surface.

[0034] The number of inclined surfaces and the number of unevenness described with reference to FIG. 4 are examples. As long as the unevenness appears alternately, the number thereof is not limited, but a suitable number is limited according to the size of the female nut 1B. For example, when the size of the female nut 1B is small, the number is small, and when the size of the female nut 1B is large, the number can be increased. Further, as long as the convex portion or the concave portion of the uneven inclined surface is provided by increasing or decreasing the inclination of the inclined surface and a shape corresponding to the uneven inclined surface is formed, the inclination does not have to be a constant angle. Next, a method of using the set nut composed of the female nut 1B and the male nut 1A according to Embodiment 1 of the present invention will be described in detail.

[0035] FIG. 7 is a front view showing a partial cross section showing a state in which the fastened body 3 is fastened between the set nut according to Embodiment 1 of the present invention and the bolt 2. FIG. 7 shows a state in which the fastened body 3 is fastened between the bolt 2 via the washer 7 using the set nut. The fastened body 3 is a steel plate having a thickness, and a through hole 3a through which the male screw portion 2a of the bolt 2 can be inserted is formed.

[0036] First, prepare a set nut, i.e., a concave nut 1B and a convex nut 1A. Next, insert the annular ridge portion 5 (the tip surface 5b thereof) of the convex nut 1A into the annular stepped portion 6 of the concave nut 1B, and sandwich the object to be fastened 3 via the bolt 2. Then, when the female screw holes 4a of the concave nut 1B and the convex nut 1A are respectively screwed onto the male screw portion 2a of the bolt 2, the ceiling surface 6b of the concave nut 1B and the tip surface 5b of the convex nut 1A, i.e., the opposing uneven inclined surfaces, slide upward and are fixed near the apex by the opposing uneven inclined surfaces.

[0037] Thus, according to Embodiment 1 of the present invention, by screwing the concave nut 1B and the convex nut 1A via the bolt 2, the concave nut 1B and the convex nut 1A are loaded (pressured) vertically via the object to be fastened 3 and the bolt 2, and are fixed near the apex by the opposing uneven inclined surfaces, so they do not loosen.

[0038] Further, according to Embodiment 1 of the present invention, the concave nut 1B and the convex nut 1A are fixed by being loaded (pressured) vertically, and since they are not fixed by eccentric fitting, no load is applied to the left and right (sides). Therefore, even in the fixed state, the centers of gravity of the concave nut 1B and the convex nut 1A coincide (the centers of gravity do not shift). As a result, even if the concave nut 1B and the convex nut 1A are rotated at high speed about the central axis C, the concave nut 1B and the convex nut 1A can rotate smoothly without wobbling.

[0039] Further, according to Embodiment 1 of the present invention, the concave nut 1B and the convex nut 1A are fixed by being loaded (pressured) vertically, and since they are not fixed by eccentric fitting, no load is applied to the left and right (sides). As a result, no gap is generated between the concave nut 1B and the convex nut 1A even in the fixed state. That is, moisture and dust are less likely to enter the gap between the concave nut 1B and the convex nut 1A in the fixed state, so the risk of leading to corrosion can be reduced.

[0040] Also, according to Embodiment 1 of the present invention, when screwing the concave nut 1B and the convex nut 1A onto the bolt 2, the annular ridge portion 5 of the convex nut 1A is fitted into the annular stepped portion 6 of the concave nut 1B, and the bolt 2 is used to sandwich the fastened body 3 and then screwed together to be fixed. That is, the set nut according to Embodiment 1 of the present invention can be easily constructed. In Embodiment 1 of the present invention, the structure of the present invention is applied to a so-called hexagonal nut, but the structure of Embodiment 1 of the present invention can also be applied to other types of nuts.

[0041] Also, in Embodiment 1 of the present invention, the set nut, that is, the concave nut 1B and the convex nut 1A, are formed of a metal such as SUS, but it is not limited thereto. They may be formed of carbon steel, or other alloy materials such as alloy steel and stainless steel, or non-metal materials such as rubber, plastic, and ceramic, and the same effect can be obtained. [Embodiment 2]

[0042] In Embodiment 1, the set nut composed of the concave nut 1B and the convex nut 1A was described. In Embodiment 2, a double nut using two nuts of the same shape stacked together will be described.

[0043] FIG. 8 is a perspective view of the nut 1C constituting the double nut according to Embodiment 2 of the present invention as viewed from above. FIG. 9 is a perspective view of the nut 1C constituting the double nut according to Embodiment 2 of the present invention as viewed from below. FIG. 10 is a front view of the nut 1C shown in FIG. 8, and FIG. 11 is a plan view of the nut 1C shown in FIG. 8. FIG. 12 is a bottom view of the nut 1C shown in FIG. 8, and FIG. 13 is a left side view of the nut 1C shown in FIG. 8. In this Embodiment 2, the annular stepped portion 6 provided on the concave nut 1B and the annular ridge portion 5 provided on the convex nut 1A are formed on each of the two nuts 1C constituting the double nut. Incidentally, since the other points are the same as those in Embodiment 1, the same reference numerals are given to the same parts as those in Embodiment 1.

[0044] Nut 1C is used as a double nut formed by stacking two nuts of the same shape. Nut 1C is a so-called hexagonal nut and has a nut body 4 that forms a hexagonal shape in plan view. Nut 1C has a female thread hole 4a that penetrates along the central axis C at the center of the nut body 4, and the female thread hole 4a can be screwed onto the male thread portion 2a of a bolt 2 described later.

[0045] In nut 1C, an annular ridge portion 5 that protrudes in the direction along the central axis C and extends in the circumferential direction around the central axis C is provided at the opening peripheral edge on one side (the upper side in FIGS. 8, 10, and 13) of the female thread hole 4a.

[0046] As shown in FIGS. 8, 10, and 13 for example, the annular ridge portion 5 includes an outer peripheral surface 5a that extends parallel to the central axis C of the female thread hole 4a in the protruding direction of the annular ridge portion 5, and a tip surface 5b that is the tip surface in the protruding direction (the upward direction in FIGS. 8, 10, and 13). Also, as shown in FIG. 11 for example, the outer periphery and inner periphery of the annular ridge portion 5 form a perfect circular shape when viewed from the direction of the central axis C. Note that a thread that is continuous with the thread of the female thread hole 4a is formed on the inner peripheral surface of the annular ridge portion 5.

[0047] The tip surface 5b is provided so as to be continuous with the outer peripheral surface 5a and to extend in the circumferential direction around the central axis C. Also, as shown in FIGS. 8, 10, and 13 for example, irregularities (irregular inclined surfaces) formed by inclined surfaces are provided on the tip surface 5b. Note that the concave portions of the irregular inclined surfaces correspond to a shape in which a part of the upper portion of the outer peripheral surface 5a is shaved as shown in FIGS. 10 and 13, but are obtained by providing an inclined surface having a gentle decreasing inclination. Thus, the concave portions of the irregular inclined surfaces are concave portions formed by an inclined surface having a decreasing inclination. Conversely, the convex portions of the irregular inclined surfaces are convex portions formed by an inclined surface having an increasing inclination.

[0048] In the example shown in FIG. 11, inclined surfaces 51 to 56 are provided on the front end surface 5b. The vicinity of the boundary (near the boundary line in FIG. 11) continuous with the inclined surfaces 51 and 52 is, for example, a concave portion, and the vicinity of the boundary (near the boundary line in FIG. 11) continuous with the inclined surfaces 51 and 56 is a convex portion. Thus, the vicinity of the boundary line in FIG. 11 is a convex or concave portion of the concavo-convex inclined surface.

[0049] Note that the number of inclined surfaces and the number of concavo-convex portions described with reference to FIG. 11 are merely examples. As long as the concavo-convex portions appear alternately, the number thereof is not limited, but a suitable number is limited according to the size of the nut 1C. For example, when the size of the nut 1C is small, the number is small, and when the size of the nut 1C is large, the number can be increased. Further, as long as convex or concave portions of the concavo-convex inclined surface can be provided by increasing or decreasing the inclination of the inclined surface, the inclination does not have to be a constant angle.

[0050] Further, in the nut 1C, an annular stepped portion 6 that is recessed in a stepped manner in the direction along the central axis C and extends in the circumferential direction around the central axis C is provided at the peripheral edge of the opening on the other side (the lower side in FIGS. 9, 10, and 13) of the female screw hole 4a.

[0051] The annular stepped 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 C. Specifically, as shown in FIGS. 9, 10, and 13, for example, the annular stepped portion 6 extends parallel to the central axis C of the female screw hole 4a in the recessed direction (the upward direction in FIGS. 9, 10, and 13) of the annular stepped portion 6, and has an inner peripheral surface 6a having a shape corresponding to the outer peripheral surface 5a, and a ceiling surface 6b that is a stepped portion of the annular stepped portion 6 that is recessed and a surface of a portion connected to the female screw hole 4a. The outer periphery and the inner periphery of the annular stepped portion 6 are circular when viewed from the direction of the central axis C, as shown in FIG. 12, for example.

[0052] The ceiling surface 6b is provided so as to be continuous with the inner peripheral surface 6a and to extend in the circumferential direction about the central axis C. Further, as shown in FIGS. 9, 10, and 13, for example, the ceiling surface 6b is provided with unevenness (uneven inclined surface) formed by inclined surfaces. The uneven inclined surface provided on the ceiling surface 6b has a shape corresponding to the uneven inclined surface provided on the tip surface 5b.

[0053] In the example shown in FIG. 12, inclined surfaces 61 to 66 are provided on the ceiling surface 6b, and the vicinity of the boundary (near the boundary line in FIG. 12) continuous with the inclined surfaces 61 and 62 is, for example, a concave portion, and the vicinity of the boundary (near the boundary line in FIG. 12) continuous with the inclined surfaces 61 and 66 is a convex portion. Thus, the vicinity of the boundary line in FIG. 12 is a convex or concave portion of the uneven inclined surface.

[0054] Note that the number of inclined surfaces and the number of unevenness described with reference to FIG. 12 are examples. The number is not limited as long as the unevenness appears alternately, but a suitable number is limited according to the size of the nut 1C. For example, when the size of the nut 1C is small, the number is small, and when the size of the nut 1C is large, the number can be increased. Further, as long as a convex or concave portion of the uneven inclined surface is provided by increasing or decreasing the inclination of the inclined surface and the shape corresponding to the uneven inclined surface is formed, the inclination does not have to be a constant angle. Next, a method of using the double nut according to Embodiment 2 of the present invention will be described in detail.

[0055] FIG. 14 is a front view showing a state in which a fastened body 3 is fastened between the double nut according to Embodiment 2 of the present invention and the bolt 2. FIG. 15 is a front view showing a partial cross-section of a state in which a fastened body 3 is fastened between the double nut according to Embodiment 2 of the present invention and the bolt 2. FIGS. 14 and 15 show a state in which a fastened body 3 is fastened via a bolt 2 using a double nut in which two nuts 1C are stacked.

[0056] First, prepare two nuts 1C. Next, insert the annular ridge portion 5 of one of the two prepared nuts 1C into the annular stepped portion 6 of the other nut 1C, stack the two nuts 1C, and then sandwich the object to be fastened 3 via the bolt 2. Then, when the female screw holes 4a of the two nuts 1C are screwed onto the male screw portion 2a of the bolt 2, the opposing ceiling surfaces 6b and tip surfaces 5b in the two stacked nuts 1C, that is, the opposing uneven inclined surfaces, slide upward and are fixed near the apex by the opposing uneven inclined surfaces.

[0057] Thus, according to the second embodiment of the present invention, by screwing the double nut via the bolt 2, the two opposing nuts 1C constituting the double nut are loaded (pressured) vertically by the object to be fastened 3 and the bolt 2, and are fixed near the apex by the opposing uneven inclined surfaces, so they do not loosen.

[0058] Also, according to the second embodiment of the present invention, the two opposing nuts 1C constituting the double nut are fixed by being loaded (pressured) vertically, and since they are not fixed by eccentric fitting, no load is applied to the left and right (sides). Therefore, even in the fixed state, the centers of gravity of the two nuts 1C coincide (the center of gravity does not shift). As a result, even if the two nuts 1C are rotated at high speed around the central axis C, the two nuts 1C can rotate smoothly without wobbling.

[0059] Also, according to the second embodiment of the present invention, the two opposing nuts 1C constituting the double nut are fixed by being loaded (pressured) vertically, and since they are not fixed by eccentric fitting, no load is applied to the left and right (sides). As a result, no gap is generated between the two nuts 1C even in the fixed state. That is, it is difficult for moisture and dust to enter the gap between the two nuts 1C in the fixed state, so the risk of leading to corrosion can be reduced.

[0060] Also, according to Embodiment 2 of the present invention, when screwing the two superposed nuts 1C that constitute the double nut onto the bolt 2, the annular ridge portion 5 of one nut 1C is fitted into the annular stepped portion 6 of the other nut 1C, and it can be fixed simply by screwing while sandwiching the fastened body 3 via the bolt 2. That is, the double nut according to Embodiment 2 of the present invention can be easily constructed. In addition, in Embodiment 2 of the present invention, the structure of the present invention is applied to a so-called hexagonal nut, but the structure of Embodiment 2 of the present invention can also be applied to other types of nuts.

[0061] Also, in Embodiment 2 of the present invention, the two nuts that constitute the double nut are formed of a metal such as SUS, for example, but are not limited thereto. They may be formed of carbon steel, other alloy materials such as alloy steel and stainless steel, non-metal materials such as rubber, plastic, and ceramic, and the same effects can be obtained. As described above, some embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0062] For example, an annular ridge portion similar to the above-described annular ridge portion 5, that is, an annular ridge portion provided with an uneven inclined surface on the tip surface, may be provided on the fastened body 3 shown in FIG. 7 or FIG. 15. In this case, since the fastened body 3 has the function of the lower nut (convex nut 1A or one nut 1C), the lower nut (convex nut 1A or one nut 1C) becomes unnecessary.

[0063] That is, in this case, the annular ridge portion of the fastened body 3 may be fitted and screwed only into the upper nut (concave nut 1B or the other nut 1C) through the bolt 2 passing through the through hole 3a of the fastened body 3. As a result, the ceiling surface 6b of the upper nut and the tip surface of the fastened body 3, that is, the opposing uneven inclined surfaces slide upward and are fixed near the apex by the uneven inclined surfaces of each other.

[0064] Therefore, by screwing the fastened body 3 and the upper nut via the bolt 2, the fastened body 3 and the upper nut are loaded (pressured) vertically via the bolt 2 and are fixed near the apex by the opposing uneven inclined surfaces of each other, so that they do not loosen.

[0065] Here, for example, the fastened body 3 may be a wheel of a nut fixing type vehicle having an annular ridge portion provided with an uneven inclined surface on the tip surface, and the upper nut may be a wheel nut provided with an uneven inclined surface on the ceiling surface. In such a case, for example, a wheel having the annular ridge portion 5 of the convex nut 1A (lower nut) shown in FIG. 2 is formed by press molding, and the concave nut 1B (upper nut) shown in FIG. 1 may be fastened to the bolt. When this wheel is fixed to the vehicle body, the upper nut does not loosen even against vibration, so that this wheel is difficult to come off in a use scene where vibration occurs such as during traveling. Note that making the fastened body 3 a wheel of a nut fixing type vehicle and the upper nut a wheel nut is an example, and it may be applied in other combinations.

Industrial Applicability

[0066] The present invention is suitable for a set nut or a double nut that prevents loosening and falling off from a bolt when fastening a fastened body to the bolt.

Explanation of Signs

[0067] 1A Convex nut 1B Concave nut 1C Nut (double nut) 2 Bolt 2a Male screw portion 3 Fastened object 3a Through-hole 4 Nut body 4a Female thread hole 5 Annular rib portion 5a Outer peripheral surface 5b Front end surface 6 Annular step portion 6a Inner peripheral surface 6b Ceiling surface 7 Washer 51 - 56, 61 - 66 Inclined surfaces C Central axis

Claims

1. A set nut composed of a lower nut and an upper nut having female screw holes that thread onto the male screw portion of a bolt along a central axis, and configured to prevent the bolt from falling off by overlapping the lower nut and the upper nut and threading their respective female screw holes onto the male screw portion of the bolt, wherein: In the lower nut, An annular protrusion is provided on the opening periphery on one side of the female screw hole, protruding in the direction along the central axis and extending circumferentially around the central axis. In the annular protrusion, an uneven inclined surface, which is an unevenness formed by an inclined surface, is provided on the tip surface, which is the surface at the tip in the protruding direction. In the upper nut, An annular step is provided on the opening periphery on the other side of the female screw hole, recessed in a stepped manner in the direction along the central axis and extending circumferentially around the central axis. In the annular step, an uneven inclined surface is provided on the ceiling surface, which is the surface of the recessed stepped portion and the portion connected to the female screw hole. The annular step has a shape corresponding to the shape of the annular protrusion so that the annular protrusion can be fitted in the direction along the central axis. The uneven inclined surface provided on the ceiling surface has a shape corresponding to the uneven inclined surface provided on the tip surface. Set nut.

2. A double nut formed by overlapping two nuts of the same shape having female screw holes that thread onto the male screw portion of a bolt along a central axis, and configured to prevent the bolt from falling off by overlapping the two nuts and threading their respective female screw holes onto the male screw portion of the bolt, wherein: An annular protrusion is provided on the opening periphery on one side of the female screw hole, protruding in the direction along the central axis and extending circumferentially around the central axis. In the annular protrusion, an uneven inclined surface, which is an unevenness formed by an inclined surface, is provided on the tip surface, which is the surface at the tip in the protruding direction. An annular step is provided on the opening periphery on the other side of the female screw hole, recessed in a stepped manner in the direction along the central axis and extending circumferentially around the central axis. In the annular step, an uneven inclined surface is provided on the ceiling surface, which is the surface of the recessed stepped portion and the portion connected to the female screw hole. The annular step has a shape corresponding to the shape of the annular protrusion so that the annular protrusion can be fitted in the direction along the central axis. The uneven inclined surface provided on the ceiling surface has a shape corresponding to the uneven inclined surface provided on the tip surface. Double nut.

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