JP2023054507A - Locking nut and fastening method of the same - Google Patents

Abstract

To provide a locking nut which can accurately position two nuts in a circumferential direction to prevent looseness of both nuts without fail, has a simple structure, and can achieve low manufacturing costs.SOLUTION: A locking nut 1 according to the invention comprises two nuts 2, 3 which threadedly engage with a bolt 10, joint surfaces of these two nuts 2, 3 are formed as taper surfaces 2A, 3A inclining relative to a surface orthogonal to an axis CL of the bolt 10 only by a predetermined angle θ. The locking nut 1 is formed provided with a positioning structure including: a positioning pin (an engagement projection) 4 which is provided protruding on one 3A of the taper surfaces; engagement holes (engagement recessed parts) 51 formed at two positions facing the other taper surface 2A in a radial direction; and a guide (a guide part) 6 formed at the other taper surface 2A and including a groove which allows the positioning pin 4 to move between two engagement holes 52.SELECTED DRAWING: Figure 5

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking double nut (hereinafter also referred to as a locking nut) capable of preventing loosening after being tightened on a bolt with a simple structure, and a tightening method thereof.

When a member to be fastened is fastened with a bolt and a nut screwed thereon, a minute play (clearance) is provided between the threads of the bolt and the nut so that the nut turns smoothly. Even if the nut is tightened with a large torque, the frictional force acting between the member to be fastened and the head of the bolt and between the nut and the member to be fastened is limited. For this reason, particularly in machines that vibrate a lot, such as construction machines, machine tools, and vehicles, there is a problem that the nuts fastened to the bolts loosen due to the vibrations. As one of the means for solving such problems, locking double nuts are often used.

The anti-loosening nut is for tightening two nuts on a bolt and preventing the loosening of these nuts by the frictional force generated between the two nuts. .

For example, in Patent Document 1, after one thin nut and the thick nut that are joined at the tapered surfaces are integrally tightened to the bolt, the thin nut is further tightened within half a turn. A self-locking nut (combination nut) has been proposed.

Patent Document 2 discloses a convex first nut formed with a right female thread and a small pitch left male thread to be screwed to a bolt, and a right female thread and a left female thread on the upper and lower inner circumferences. A self-locking nut has been proposed, which is composed of a recessed second nut formed with right-handed helical inclined surfaces formed on the inner surface of the flange portion of the first nut and the lower end surface of the second nut, respectively. there is

Furthermore, Patent Document 3 proposes a locking nut in which a notch having a constant taper angle is formed between a first nut portion and a second nut portion, and a connecting portion is formed by the notch. there is According to this locking nut, when the second nut portion is forcibly rotated in the indicated direction with respect to the first nut portion, the connecting portion is sheared, and the notches of the first nut portion and the second nut portion face each other. Since the surfaces are pressed against each other and the first nut portion and the second nut portion are pressed against the bolt toward the axial center of the bolt, loosening of the first nut portion and the second nut portion is prevented. .

JP-A-53-110765 Japanese Patent Publication No. 62-049489 Japanese Patent No. 3574698

However, the locking nut proposed in Patent Document 1 requires deformation of the thread of the bolt or deformation of the upper nut to tighten the thin upper nut within half a turn, which is unrealistic. There is a problem that Further, as shown in FIG. 17(b), even if a force is applied in the direction of the bolt axis, the force in the direction toward the axis of the bolt is balanced. Although the frictional force for contacting the screw thread of the nut increases, the effect of pressing against the bolt shaft center side (caulking force) is small.

In addition, the locking nut proposed in Patent Document 2 has a convex portion and a concave portion that are screwed or fitted together, so that the structure of each nut is complicated, and there is a problem that the manufacturing cost is high. be. In addition, the bolt disclosed in Patent Document 2 is also tightened in the axial direction of the bolt to prevent it from loosening.

Furthermore, in the locking nut proposed in Patent Document 3, after the connecting portion is sheared by tightening the first nut portion and the second nut portion integrated via the connecting portion to the bolt, the second nut By rotating the portion (upper nut) with respect to the first nut portion (lower nut) by a predetermined angle, the first nut portion and the second nut portion are pressed against each other in the axial direction of the bolt. As in the case, the effect of press-fitting to the shaft center side of the bolt is small, and there is a problem that the loosening of both nut portions cannot always be reliably prevented.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of conventional locking nuts. After tightening the bolt, by rotating the upper nut half a turn (180°) in the opposite direction (loosening direction) and positioning it accurately, loosening of both nuts is reliably prevented, and the structure is simple to keep the manufacturing cost low. To provide an anti-loosening nut and its tightening method.

A locking nut according to the present invention for achieving the above object comprises two nuts, an upper nut and a lower nut, which are screwed onto a bolt. A locking nut having a tapered surface inclined at a predetermined angle with respect to the upper nut and the lower nut, wherein the upper nut and the lower nut have an engaging projection protruding at one location near the outer circumference of one of the tapered surfaces, and the other Engagement recesses formed at two radially opposite locations in the vicinity of the outer circumference of the tapered surface, and engagement recesses engaged with the engagement protrusions formed by the engagement protrusions and the engagement recesses are formed on the upper surface. and a guide part that permits and restricts the nut to be rotated by half to the loosening side.

Further, in the locking nut tightening method according to the present invention, the upper nut and the lower nut are joined such that the engaging protrusion is engaged with one of the engaging recesses and the tapered surfaces of the nuts are parallel to each other. After tightening the upper nut integrally with the bolt, the upper nut is rotated halfway in the loosening direction to engage the engaging protrusion with the other engaging recess, and the tightened upper nut is loosened with respect to the lower nut. It is characterized by positioning at a position half-rotated in the direction.

According to the present invention, the upper nut and the lower nut are integrated with the bolt in a state in which the engaging projection of the lower nut is engaged with one of the engaging recesses of the upper nut and the tapered surfaces thereof are joined in parallel. When the upper nut is rotated halfway in the loosening direction after being tightened as is, the engaging protrusion is engaged with the other engaging recess to accurately position the upper nut relative to the lower nut in the circumferential direction. The convex portions of the tapered surface of the nut overlap and press each other, and a high pressing force (a force perpendicular to the tapered surface) always acts on the pressing portion. Since the horizontal component of this pressing force presses both nuts in the axial direction, there is no play between the female threads of the nuts and the male threads of the bolt. As a result, loosening of the nuts is reliably prevented. be

In addition, the two nuts that constitute the locking nut according to the present invention are obtained by cutting one nut member obliquely at the middle part in the height direction, so that the upper nut and the lower nut having tapered surfaces at the same angle can be easily manufactured at the same time. can be manufactured at a low cost.

FIG. 4 is a front view showing a state where the locking nut according to Embodiment 1 of the present invention is screwed onto the bolt; 1 is a front view of a locking nut according to Embodiment 1 of the present invention; FIG. FIG. 3 is a view in the direction of arrows AA in FIG. 2 (bottom view of the upper nut); FIG. 3 is a view in the direction of arrows BB in FIG. 2 (a plan view of the lower nut); 4(a) to 4(c) are fragmentary front views showing a method for tightening the locking nut according to the first embodiment of the present invention in the order of steps; FIG. (a) is a cross-sectional view along the DD line in FIG. 5(a), (b) is a cross-sectional view along the EE line in FIG. 5(b), and (c) is a cross-sectional view along the FF line in FIG. 5(c). . (a) shows, in the locking nut according to Embodiment 1 of the present invention, when the upper nut is rotated half a turn after tightening the nut with a gap of 1/2 pitch between the tapered surfaces of both nuts. Schematic diagram for explaining the state of the tapered surfaces of both nuts, (b) is the same locking nut as in FIG. Schematic diagram for explaining the state of the tapered surface in which the upper nut cannot be rotated halfway even if the upper nut cannot be rotated halfway after tightening. FIG. 4 is a front view showing another form of the locking nut according to Embodiment 1 of the present invention; FIG. 11 is a cutaway front view showing a state in which a locking nut according to Embodiment 2 of the present invention is used to fasten two plate members with bolts; The front view of the locking nut according to Embodiment 2 of the present invention. FIG. 11 is a view in the direction of arrows GG in FIG. 10 (bottom view of the upper nut); FIG. 11 is a view in the direction of arrows HH in FIG. 10 (a plan view of the lower nut); The front view of the locking nut according to Embodiment 3 of the present invention. FIG. 14 is a plan view of the locking nut of FIG. 13; FIG. 14 is a front view of the state in which the locking nut of FIG. 13 is functioning; FIG. 4 is a schematic front view for explaining the dimensions of each part of the upper nut of the locking nut and the force acting on the upper nut from the lower nut when it is half-rotated in the opposite direction. (a) and (b) Schematic for explaining the force acting on one thread of the threaded surface (contact surface) of the upper nut and bolt shown in FIG. 17(a) with reference to FIG. 17(b) Enlarged view. FIG. 11 is a schematic front view for explaining deformation of an upper nut having the same configuration as the upper nut of the third embodiment when it is rotated halfway;

Embodiments 1 to 3 of the present invention will be sequentially described below with reference to the accompanying drawings.

<Embodiment 1>
1 is a side front view showing a state in which a locking nut according to Embodiment 1 of the present invention is screwed onto a bolt; FIG. 2 is a front view of the locking nut according to Embodiment 1 of the present invention; 3 is a view in the direction of arrow AA in FIG. 2 (bottom view of the upper nut), and FIG. 4 is a view in the direction of arrow BB in FIG. 2 (plan view of the lower nut).

A locking nut 1 according to Embodiment 1 is composed of two nuts 2 and 3 that are screwed onto a bolt 10, as shown in FIG. Hereinafter, the nut 2 on the upper side of FIG. 1 is called "upper nut 2", and the nut 3 on the lower side is called "lower nut 3".

As shown in FIGS. 3 and 4, the upper nut 2 and the lower nut 3 are hexagonal nuts, and the pitch P (see FIG. 1 ) are formed with female threads 2a and 3a having the same pitch P as that shown in FIG.

As shown in FIGS. 1 and 2, the joint surfaces of the upper nut 2 and the lower nut 3, that is, the bottom surface of the upper nut 2 and the upper surface of the lower nut 3, are surfaces perpendicular to the axis CL of the bolt (see FIG. 1 and a horizontal plane in FIG. 2). Here, as shown in FIG. 2, on the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3, the thicker portions are convex portions 2A1 and 3A1, and the thinner portions are concave portions 2A2. , 3A2.

By the way, as shown in FIGS. 2 to 4, if the horizontal component of the length of each tapered surface 2A, 3A of the upper nut 2 and the lower nut 3 is L, the inclination angle θ of each tapered surface 2A, 3A will be described later. is set to a value represented by the following formula (1) for the reason described below.
θ≧tan−1(P/2L) (1)

In the first embodiment, as shown in FIGS. 2 and 4, a short columnar positioning pin 4 as an engaging projection is provided at one circumferential position on the convex portion 3A1 of the tapered surface 3A of the lower nut 3. erected vertically. Here, the height h (see FIG. 2) of the positioning pin 4 is set to approximately the same height as 1/2 (0.5P) of the pitch P (see FIG. 1) of the male screw 10a of the bolt 10. . That is, the height h of the positioning pin 4 and the pitch P of the male screw 10a of the bolt 10 are given the relationship represented by the following equation (2).
h≈P/2 (2)

Also, as shown in FIG. 3, two locations on the same circumference facing each other on the diameter of the tapered surface 2A of the upper nut 2 (two locations separated by an angle of 180° in the circumferential direction, that is, the convex portions 2A1 of the tapered surface 2A and recessed portion 2A2) are provided with two circular engaging holes 51 and 52 as an example of an engaging recessed portion for selectively engaging a cylindrical positioning pin 4 erected on the lower nut 3. These two engagement holes 51 and 52 are located at both ends of a guide 6 including a semi-circular groove functioning as a guide formed in the tapered surface 2A. Here, when the guide 6 is a groove, the groove is formed in a semicircular shape centering on the axis of the upper nut 2, and the width w of the groove is approximately equal to the inner diameter φd of the engagement holes 51 and 52. (w=φd), and the depth s is set to a value approximately equal to the height h of the pin 4 (s=h). The inner diameter φd of the engaging holes 51 and 52 is set slightly larger than the outer diameter φD of the positioning pin (φd>φD).

The above-described positioning pin 4, two engagement holes 51 and 52 with which the positioning pin 4 is selectively engaged, and a guide for slidingly guiding the positioning pin 4 between the two engagement holes 51 and 52. Reference numeral 6 constitutes an example of a positioning structure for accurately positioning the upper nut 2 half-rotated relative to the lower nut 3 in the loosening direction. Although the guide 6 is shown as a groove in FIGS. 2 and 3, the tapered surface 2A of the upper nut 2 overcomes the positioning pin 4 when the upper nut 2 starts to be rotated halfway in the loosening direction, so that the bottom is tapered. Some grooves are shallow.

Next, a method of tightening the locking nut 1 of Embodiment 1 configured as described above will be described below with reference to FIGS. 5 and 6. FIG.
FIGS. 5(a) to 5(c) are fragmentary front views showing the order of steps for fastening two plate members using the locking nut and bolt according to the first embodiment, and FIGS. 6(a) to 6(c). ) are cross-sectional views of the DD line, EE line, and FF line of FIGS. 5(a) to (c), and FIG. It is a figure which shows typically the state of each taper surface when 2 is rotated halfway in the loosening direction.

As shown in FIG. 5, when two plate members 11 and 12 are fastened using the locking nut 1 and the bolt 10 according to the first embodiment, as shown in FIG. A bolt 10 is passed from below through circular bolt holes 11a and 12a formed in the two plate members 11 and 12, respectively, and the head 10A of the bolt 10 is brought into contact with the bottom surface of the plate member 12 on the lower side. The locking nut looks as if the upper nut 2 and the lower nut 3 are integrated by bringing the tapered surfaces 2A and 3A into surface contact with the portion protruding upward from the upper plate member 11 of the threaded portion 10B of the bolt 10. 1 are screwed together using a socket wrench. Specifically, the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 1 are joined to each other, and the positioning pin 4 erected on the lower nut 3 is positioned as shown in FIG. 6(a). 5 (a ) in the direction of the arrow (opposite to tightening).
Then, the upper nut 2 and the lower nut 3 move downward along the threaded portion 10B of the bolt 10 together, and as shown in FIG. abut. From this state, the nuts 2 and 3 are tightened to the bolt 10 with a predetermined torque.

After that, the upper nut 2 is rotated by half (180°) in the direction of loosening (in the direction of the arrow shown in FIG. 5(b)). This half-rotation of the upper nut 2 in the loosening direction causes the positioning pin 4 erected on the tapered surface 3A of the lower nut 3 to be formed on the tapered surface 2A of the upper nut 2, as shown in FIG. 6(b). It slides and guides the semi-circular groove-shaped guide 6 which is formed. That is, during the half-rotation process of the upper nut 2 in the loosening direction, the guide 6 formed on the tapered surface 2A of the upper nut 2 as shown in FIG. It is moved half a turn from the position of (a).

When the upper nut 2 rotates halfway in the direction of loosening, as shown in FIG. are engaged to prevent further rotation of the upper nut 2 in the loosening direction, and the upper nut 2 is accurately positioned with respect to the lower nut 3 in the circumferential direction. Further, when the upper nut 2 rotates halfway in the loosening direction, the male thread 10a of the bolt 10 moves in the direction (upward) in which the concave portion 2A2 of the tapered surface 2A of the upper nut 2 moves away from the convex portion 3A1 of the tapered surface 3A of the lower nut 3. It moves by half the pitch P (=P/2). Then, as shown in FIG. 5(c), the convex portion 2A1 of the tapered surface 2A of the upper nut 2 overlaps the convex portion 3A1 of the tapered surface 3A of the lower nut 3, and the concave portions of the tapered surfaces 2A and 3A of the nuts 2 and 3 are overlapped. A predetermined gap δ is formed between 2A2 and 3A2.

Next, the inclination angle .theta. of the tapered surfaces 2A and 3A for obtaining the anti-loosening effect by rotating the upper nut 2 halfway in the loosening direction will be described with reference to FIG. 7(a).
After tightening the upper and lower nuts 2 and 3 with a predetermined torque, when the upper nut 2 is rotated halfway in the loosening direction, the point a of the convex portion 2A1 of the tapered surface 2A of the upper nut 2 before the halfway rotation moves upward by P/2. 7, the point b of the recessed portion 2A2 of the tapered surface 2A of the upper nut 2 moves to the point b' in FIG. δ is formed.
Therefore, the upper nut 2 rotates half in the direction of loosening, and as shown in FIG. In a state where the point a of the surface 2A and the point b of the convex portion 3A1 of the tapered surface 3A of the lower nut 3 are in contact (point contact), the inclination angles of the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3 are θ is represented by the following equation (3).
θ=tan−1(P/2L) (3)

However, in reality, even if the upper nut 2 and the lower nut 3 are tightened integrally with the desired torque and then the upper nut 2 is rotated halfway in the loosening direction, the point a on the convex portion 2A1 of the tapered surface 2A of the upper nut 2 does not reach the point a. cannot reach the point b of the convex portion 3A1 of the tapered surface 3A of the lower nut 3. The reason is as follows. 7(b), when the tapered surfaces 2A and 3A of the nuts 2 and 3 are joined, the point a of the upper nut 2 is positioned from the inner diameter edge x of the thread 2a of the upper nut 2. located below. For this reason, even if the tightened upper nut 2 is rotated halfway to the loosening side and the portion of the inner diameter edge x of the screw is raised by half a pitch so that it becomes the direction 2' indicated by the two-dot chain line, the point Before turning a half way, the projection 3A1 of the lower nut 3 hits the front side of the point b, and the upper nut 2 cannot be rotated further.
In order for point a to reach point b in a half rotation of the upper nut 2, the tapered surface 2A of the upper nut 2 must be deformed, or when the upper and lower nuts 2 and 3 are tightened, the tapered surfaces of both nuts 2 and 3 must be deformed. Between 2A and 3A, it is necessary to keep a gap of 1/2 screw pitch. Therefore, FIG. 7(a) shows an example in which a gap corresponding to 1/2 of the thread pitch is previously provided between the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3. FIG.
In FIG. 7(a), when the upper nut 2 is rotated halfway in the loosening direction, in order to bring the points a and b into surface contact, θ in the above equation (3) should be increased or half It is conceivable to set the gap between the tapered surfaces of the upper nut 2 and the lower nut 3 to 1/2 or less of the thread pitch before the start of rotation.

The above equation (3) shows the inclination angle θ of each tapered surface 2A, 3A when the convex portions 2A1, 3A1 of the tapered surfaces 2A, 3A of the upper nut 2 and the lower nut 3 are in point contact with each other. If the angle θ is greater than the value represented by the formula (3), that is,
θ>tan ⁻¹ (P/2L) (4)
, the projections 2A1 and 3A1 of the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3 are in surface contact with each other. When the projections 2A1 and 3A1 on the tapered surfaces of the upper nut 2 and the lower nut 3 are in surface contact with each other, the thickness of the upper nut 2 is made thinner than the thickness of the lower nut 3 as shown in FIG. Alternatively, by configuring the upper nut 2 with a material having a lower hardness than the material of the lower nut 3, the upper nut 2 is more likely to be elastically deformed against the lower nut 3 after half a turn. and the convex portions 2A1 and 3A1 of the tapered surfaces 2A and 3A of the lower nut 3 can be brought into reliable surface contact with each other.

As described above, in the locking nut 1 according to the first embodiment, the upper nut 2 and the lower nut 3 are formed on the tapered surface 2A of the upper nut 2 with the positioning pin 4 erected on the lower nut 3. After engaging with the other engaging hole 51 and tightening the bolt 10 integrally with the tapered surfaces 2A, 3A of the nuts 2, 3 joined together, the upper nut 2 is rotated halfway in the loosening direction. The upper nut 2 can be accurately positioned with respect to the lower nut 3 in the circumferential direction by allowing the positioning pin 4 to engage with the other engaging hole 52 . As a result, a high pressing force (a force perpendicular to the tapered surfaces 2A, 3A) always acts on the pressing portions where the convex portions 2A1, 3A1 of the tapered surfaces 2A, 3A of the nuts 2, 3 overlap and press each other.

16 and 17, the pressing force acting on the contact portions when the convex portions 2A1 and 3A1 of the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3 come into contact with each other will be described. do.

In FIG. 16, for convenience of explanation of the locking action of the upper nut 2, the convex portion 2A1 of the tapered surface 2A of the upper nut 2 screwed onto the bolt 10 receives the pressing force P from the tapered surface 3A1 of the lower nut 3. It is a schematic representation of the normal nut shape.
In FIG. 16, L: thickness of upper nut 2, D: outer diameter of upper nut 2, d: inner diameter of upper nut 2, P: upward pressing force of lower nut 3 (not shown) acting on upper nut 2. (generated by contact between the tapered surface 2A of the upper nut 2 and the tapered surface 3A of the lower nut 3); do.

Now, as shown by the dotted line in FIG. 16, the moment around the contact point A between the female screw 2a of the upper nut 2 inclined by the upward pressing force P of the tapered surface of the lower nut and the male screw 10a of the bolt 10 is P× Since 1/2(D+d)=RL, the reaction force R is represented by R=P.times.(D+d).times.1/2L.
According to the above formula, in order to increase the reaction force R, (a) P should be increased, (b) D(d) should be increased, and (c) L should be decreased. Although not expressed in the formula for the reaction force R, it is conceivable to directly increase the reaction force R by deforming the upper nut 2 .

On the other hand, as an alternative to enlarging the outer diameter D of the upper nut 2, it is considered effective to attach a deformable crocodile (flange) to the nut 2 without enlarging the outer diameter of the upper nut 2 itself. It is also considered effective to reduce the thickness L of the upper nut for deformation of the upper nut.

Next, as shown in FIGS. 17(a) and 17(b), conventional locking nuts such as Patent Documents 1 to 3, in which the contact surfaces of the upper nut and the lower nut are tapered to prevent loosening, have a sufficient locking effect. Consider the reason why you did not get it.
FIGS. 17(a) and 17(b) show the action of the upward pressing force P at the contact point between the upper nut 2 of the conventional locking nut and the bolt 10, on the contact surface of one male screw and female screw. It is a schematic diagram. FIG. 17(b) is a schematic enlarged view of one screw thread of the bolt 10 and the nut 2 of FIG. 17(a).

In FIG. 17(b), if the pressing force P=.SIGMA.p, the force ph parallel to the threads is almost balanced between the left and right threads 10a and 2a of the bolt 10 and the nut 2. In FIG. Therefore, even if the pressing force P acts in the vertical direction, if the force ph parallel to the screw threads is balanced between the contact surfaces of the left and right screw threads, the relative positions of the contact surfaces of the screw threads do not change. "Caulking force" cannot be obtained and cannot be strongly crimped. In FIG. 17B, p is the pressing force acting on one screw thread, and pn is the force component acting on the contact surface of one screw thread in the orthogonal direction.

The upper nut 2 and the lower nut 3 that constitute the locking nut 1 according to the first embodiment described above can be easily obtained by cutting one nut obliquely (at the angle of the tapered surfaces 2A and 3A) at the intermediate portion in the height direction. Since the locking nut 1 of the present invention can be manufactured in a simple manner, the structure can be simplified and the manufacturing cost can be kept low.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described below with reference to FIGS. 9 to 12. FIG.

FIG. 9 is a cutaway front view showing a state in which two plate materials are fastened with bolts in the locking nut according to the second embodiment, and FIG. 10 is a front view of the locking nut according to the second embodiment. 11 is a view along the line GG in FIG. 10 (bottom view of the upper nut), and FIG. 12 is a view along the line HH in FIG. 10 (a plan view of the lower nut). The same reference numerals are given to the same elements as those shown in FIGS. 1 to 8, and the description thereof will be omitted.

A locking nut 1A according to Embodiment 2 is composed of an upper nut 2 and a lower nut 3 with flanges (collars) 2F and 3F. The lower surface of the circular flange 2F formed integrally with the lower end surface of the upper nut 2 is a flat taper inclined by an angle θ shown in the drawing with respect to a plane (horizontal plane) perpendicular to the vertical axis CL of the bolt 10. The upper surface of a circular flange 3F, which constitutes the surface 2A and is integrally formed on the upper end of the lower nut 3, is inclined by an angle θ shown in the figure with respect to a plane (horizontal plane) perpendicular to the vertical axis CL of the bolt 10. It constitutes a flat tapered surface 3A. Here, the inclination angle .theta. of each tapered surface 2A, 3A of the upper nut 2 and the lower nut 3 is set to the value represented by the formula (1).

Also in the locking nut 1A according to the second embodiment, similarly to the locking nut 1 according to the first embodiment, the tapered surface 3A, which is the upper surface of the flange 3F of the lower nut 3, has a convex portion 3A1 side. At one position in the circumferential direction, a short columnar positioning pin 4 as an engaging projection is erected vertically (see FIGS. 10 and 12).

In addition, at two locations on the same circumference (two locations separated by an angle of 180° in the circumferential direction) facing in the radial direction of the tapered surface 2A, which is the lower surface of the flange 2F of the upper nut 2, as shown in FIG. , engagement notches 51 and 52, which are examples of engagement recesses selectively engaged with the positioning pin 4 erected on the lower nut 3, are respectively formed. These two engagement notches 51 and 52 are present at both ends of the guide 6 including semicircular grooves formed in the tapered surface 2A. Here, the positioning pin 4, two engagement notches 51 and 52 selectively engaging the positioning pin 4, and the positioning pin 4 being slidably guided between the two engagement notches 51 and 52. The guide 6 forms a positioning structure for accurately positioning the upper nut 2 with respect to the lower nut 3 in the circumferential direction. 9 to 11, reference numeral 7 denotes a counterbore formed radially inside the guide 6 on the tapered surface 2A of the upper nut 2. As shown in FIG. The counterbore 7 is provided to facilitate deformation of the two tapered surfaces 2A and 3A, but its depth and size vary depending on the thickness, diameter and material of the flange.

Therefore, in the locking nut 1A according to the second embodiment described with reference to FIGS. 9 to 12, the upper nut 2 and the lower nut 3, the positioning pin 4 erected on the lower nut 3 is engaged with one engagement notch 51 formed in the tapered surface 2A of the upper nut 2, and each taper of both nuts 2, 3 After the surfaces 2A and 3A are joined to each other and are tightened integrally with the bolt 10, the upper nut 2 is rotated halfway in the loosening direction.
Here, in order to tighten the upper and lower nuts 2 and 3 integrally to the bolt 10, the tapered surfaces 2A and 3A of both nuts 2 and 3 are joined, and the positioning pin 4 is engaged with the engagement notch 51, and then the upper and lower nuts are tightened. Tighten the nut 2 with a socket. A ratchet tooth having a serrated cross section is formed on the outer peripheral side of the counterbore portion 7 on the lower surface of the upper nut 2 to ensure that both nuts 2 and 3 rotate integrally when the upper nut 2 is tightened by the socket. You may make it complement.

In the half rotation of the upper nut 2 in the loosening direction, the upper nut 2 is rotated halfway until the positioning pin 4 is engaged with the engagement notch 52 on the other side. Since the portion where the upper nut 2 is located is the flange portion 2F which is thinner than the upper nut 2, when the upper nut 2 is rotated halfway and the convex portions 2A1 and 3a1 of the tapered surfaces 2A and 3A of the nuts 2 and 3 come into contact with each other, The flange portion 2F is slightly warped upward and can be easily rotated halfway. Therefore, the convex portion 2A1 of the tapered surface 2A of the upper nut 2 can be easily rotated halfway with respect to the convex portion 3A1 of the tapered surface 3A of the lower nut 3 so as to be accurately positioned in the circumferential direction. As a result, as in the first embodiment, there is play between the female threads 2a and 3a (see FIGS. 11 and 12) of the upper nut 2 and the lower nut 3 and the male thread 10a (see FIG. 9) of the bolt 10. (clearance) is eliminated and the flange 2F is deformed, so that the loosening of the nuts 2 and 3 can be reliably prevented.

Further, the upper nut 2 and the lower nut 3, which form the tapered surfaces 2A, 3A with the flanges 2F, 3F, which constitute the locking nut 1A according to the second embodiment, have a simple structure and can be relatively easily installed. Since it is manufactured, the manufacturing cost of the locking nut 1A can be kept low.

In the first and second embodiments described above, the positioning pin 4 is erected on the tapered surface 3A of the lower nut 3, and the two engaging holes (or engaging notches) 51 are provided on the tapered surface 2A of the upper nut 2. , 52 and a guide 6 including a groove are formed. The guides may be formed including notches and grooves. Here, the engaging hole and the engaging notch can be arbitrarily selected.

<Embodiment 3>
Next, Embodiment 3 of the present invention will be described below with reference to FIGS. 13 to 15. FIG.

The locking nut 1B of Embodiment 3 is a modified example or application example of Embodiment 2, and has the following unique configuration with respect to Embodiment 2. It is explained below.

First, the lower nut 3 is the same as the lower nut 3 of the first embodiment because the tapered surface 3A is formed on the upper surface of the lower nut itself and does not have the flange 3F. Next, the upper nut 2 has an outer diameter smaller than that of the lower nut 3, for example, about half the outer diameter of the lower nut 3. As shown in FIG. The upper nut 2 has a lower tapered surface 2A formed on a hexagonal flange 21F having the same outer diameter and outer shape as the lower nut 3 in plan view. A counterbore 7 is provided on the tapered surface 2A of the upper nut 2 for the same purpose as in the second embodiment.

The lower nut 3 is provided with a positioning pin 4 at one position on the outer circumference, while the lower surface of the flange 21F forming the tapered surface 2A of the upper nut 2 is provided with a position corresponding to the pin 4 and a position 180 degrees from that position on the flange diameter. Engagement notches 51 and 52 (or notches) for fitting the pin 4 are provided at two positions apart from each other. The locking notch may be a locking hole.

In the locking nut 1B of the third embodiment, the tapered surfaces 2A and 3A of the upper nut 2 and the lower nut 3 are parallel to each other, and the positioning pin 4 is fitted in the first engagement notch 51 to join the nuts. Two nuts 2 and 3 are integrally set on a socket wrench and screwed onto a bolt 10.例文帳に追加This point is the same as the locking nut 1 of the first embodiment described above.

When the upper nut 2 and the lower nut 3 are integrally fastened to the bolt 10 with a predetermined torque, the upper nut 2 is rotated halfway to the loosening side, and the positioning pin 4 is moved to the second engagement notch of the flange 21F of the upper nut 2. 52 and positioned. Then, the portion of the flange 21F on the outer side of the upper nut 2 where the second engagement notch 52 is provided receives an upward warping force from the convex portion 3A1 of the tapered surface 3A of the lower nut 3 and deforms. To eliminate play between the female thread of a nut 2 and the male thread of a bolt 10. - 特許庁This prevents the upper nut 2 and the lower nut 3 from loosening from the bolt 10. - 特許庁

The upper nut 2 of the above third embodiment is intended to increase the outer diameter D of the upper nut 2 and to deform the upper nut 2 as discussed in the description of the first embodiment (paragraphs 0033 and 0034). As schematically illustrated in FIG. 18 when the upper nut 2 is viewed from the front, the thickness of the nut itself and the thickness in the vertical direction are formed thin, and a hexagonal washer portion ( Flange) 2F is provided.
After tightening the upper nut 2 and the lower nut 3 formed in this manner to the bolt 10 together with a socket wrench, the upper nut 2 is rotated 180 degrees along the axis of the bolt 10 in the direction opposite to the tightening direction. 13 to 15 (washer portion 2F in FIG. 18) is deformed, the contact area between the screw thread of the bolt 10 and the screw thread of the upper nut 2 increases. The force ph parallel to the left and right screw threads described in b) is also unequal, and a large "crimping force" is obtained. It is also effective to form the upper nut 2 from a softer material because of its easily deformable properties. 13 to 15 and 18, the outer diameter D of the upper nut 2 is substantially increased because the washer portions 21F and 2F are provided even if the thickness of the upper nut 2 in the vertical direction is reduced. As a result, the reaction force R also increases.

In the first to third embodiments described above, the locking nut 1 consisting of two ordinary hexagonal nuts, the upper nut 2 and the lower nut 3, and the two flanged nuts, the upper nut 2 and the lower nut 3 and a locking nut 1B consisting of an upper nut 2 of a flanged nut and a lower nut 3 of the same type as the flange of the upper nut 2. However, the present invention is It is equally applicable to any other type of locking nut consisting of two nuts.

In addition, the application of the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the technical ideas described in the claims, the specification, and the drawings. is of course.

1, 1A, 1B Locking nut of the present invention 2 Upper nut 2A Tapered surface of lower surface of upper nut 2F, 21F Flange (flange portion) of upper nut
3 Bottom nut 3A Tapered surface on top of bottom nut 3F Flange of bottom nut 4 Positioning pin (engagement projection)
51, 52 engagement hole, engagement notch (engagement recess)
6 Guide including groove (guide part)
7 Counterbore 10 Bolt CL Bolt axis center P Bolt thread pitch θ Inclination angle of nut tapered surface

Claims (9)

A locking nut consisting of two nuts, an upper nut and a lower nut, which are screwed onto a bolt, and the joint surface of these two nuts is a tapered surface inclined at a predetermined angle with respect to the surface perpendicular to the axis of the bolt. There is
The upper nut and the lower nut are
an engaging projection projecting from one location near the outer circumference of one of the tapered surfaces;
Engagement recesses formed at two locations near the outer periphery of the other tapered surface that face each other in the diametrical direction;
a guide portion formed by the engaging projection and the engaging recess for allowing and restricting the engaging recess engaged with the engaging projection to be half-rotated toward the loosening side of the upper nut;
locking nut. The engagement projection is composed of a short columnar positioning pin,
The engagement recess is composed of two engagement holes or engagement notches into which the pin is fitted,
2. The locking nut according to claim 1, wherein said guide portion comprises a pin passage including a semicircular groove for guiding said pin formed between said two engaging recesses. The upper nut and the lower nut each have a flange portion forming the tapered surface, and the engaging projection is provided near the outer periphery of one flange portion, and the two locations are near the outer periphery of the other flange portion. The locking nut according to claim 1 or 2, wherein the engaging recess and the guide portion are formed. The upper nut has a diameter smaller than that of the lower nut, and has a hexagonal flange having substantially the same shape as the lower nut on a lower tapered surface, and the lower nut has a tapered upper surface having the same outer shape as the hexagonal flange. , the engaging protrusion is protruded near the outer periphery of the tapered surface of the lower nut, and the engaging recess and the guide are provided at two diametrical locations near the outer periphery of the hexagonal flange portion of the upper nut. The locking nut according to claim 1 or 2, wherein a portion is formed. The locking nut according to any one of claims 1 to 4, wherein the thickness of said upper nut is set thinner than the thickness of said lower nut. The locking nut according to any one of claims 1 to 5, wherein hardness of said upper nut is set lower than hardness of said lower nut. The locking nut according to any one of claims 1 to 6, wherein the inclination angle of the tapered surfaces of the upper nut and the lower nut is substantially the same as the pitch angle of the thread of the bolt. The locking nut according to any one of claims 1 to 6, wherein the tapered surface of the upper nut is formed with a counterbore portion leaving an outer peripheral edge. The locking nut tightening method according to any one of claims 1 to 8,
After the upper nut and the lower nut are integrally tightened to the bolt in a state in which the engaging projection is engaged with one of the engaging recesses and the tapered surfaces of the nuts are joined in parallel, the upper nut is loosened. The upper nut after being tightened is positioned at a position where the upper nut after being tightened is rotated halfway in the loosening direction with respect to the lower nut. How to tighten the locking nut.

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