JP2015102207A - Lock nut - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lock nut capable of increasing prevailing torque, and capable of properly engaging a friction piece and the thread of a bolt even without having the positional relationship between the friction piece and a nut body as designed.SOLUTION: On an upper surface 33 of a nut body 31, a friction piece 23 for prevailing torque generation is fixed. A thread 12 of a bolt 11 enters from a transition part 24 having no friction piece 23, the friction piece 23 is elastically deformed by engaging with the thread 12 having entered, and thereby prevailing torque is generated. A space 41 for axial interference prevention is provided between the upper surface 33 of the nut body 31 and the friction piece 23.

Description

The present invention relates to an improvement of a locking nut.

Conventionally, a pre-baling torque type locking nut that attaches a pre-ringing torque generating part such as resin or friction ring to the nut and exerts a detent action by frictional resistance with the bolt is used as a tightening means for places with a lot of vibration. Widely used.
The applicant of the present invention and the related parties have a large share of the pre-torque torque type locking nut. I am applying. In Patent Documents 1 to 3, a nut is disclosed in which a friction ring is mounted on an end surface of the nut body facing the seat surface. This friction ring is an annular body made of metal spring elasticity, and has an arc-shaped friction piece integrally projecting inward from the inner periphery of the annular body. The friction piece engages with the male screw when screwed with the bolt. This male screw is elastically deformed with the progress of the male screw, thereby generating pre-leveling torque, thereby preventing the nut from loosening. Patent Document 1 discloses a configuration in which three pieces of friction covering a range of about 60 degrees are formed at equal intervals, and a screw thread of a bolt enters from a transition portion between the pieces of friction. ing. In Patent Document 2, there is one friction piece formed over a range of about 180 degrees, and the transition portion is formed over a range of about 180 degrees. In Patent Document 3, in a nut having a relatively gentle lead angle, one friction piece is formed over a range of about 280 degrees, and the transition portion is formed over a range of about 80 degrees. ing.

As described above, various aspects have been proposed for the design of the friction piece. Generally, it is more effective to form the friction piece over a long range in the circumferential direction. The area and the degree of elastic deformation increase, and the friction torque can be increased.

On the other hand, in this kind of locking nut, adjust the positional relationship with the threaded up part of the nut body so that the thread of the bolt can smoothly enter from the transition part, It is necessary to attach to the nut end face. Specifically, when the friction ring is attached so as to be in contact with the end face of the nut, it is necessary to attach the nut body so that the threaded portion of the nut body is located at the transition portion. If this mounting accuracy is reduced, the bolt threads cannot be engaged with the friction pieces, resulting in damage to the bolt threads or friction pieces, or excessive screwing torque. The performance cannot be demonstrated. Further, if the formation range of the friction piece is lengthened in the circumferential direction, the range of the transition portion becomes small, and thus a high degree of mounting accuracy is required.

Japanese Utility Model Publication No. 46-8496 Japanese Utility Model Publication No. 61-2346 Japanese Utility Model Publication No. 5-37055

It is an object of the present invention to further improve the provision of the above-described locking nut and provide a locking nut capable of increasing the pre-leveling torque.
Another object of the present invention is to enable the friction piece and the screw thread of the bolt to be properly engaged even if the positional relationship between the friction piece and the nut body is not as designed.

The present invention includes a nut body and a friction piece for generating pre-leveling torque fixed to the top surface of the nut body. The thread of a bolt is inserted from a transition portion without the friction piece, and the friction piece enters. The loosening prevention nut that generates pre-leveling torque by engaging with the flank surface of the thread and elastically deforming it is improved. The gist thereof is to provide an interference preventing space in the axial direction between the upper surface and the friction piece.

The present invention can reduce the possibility of interference between the friction piece and the thread even when the friction piece that generates the pre-leveling torque is formed in a large range in the circumferential direction. As a result, the formation range of the friction pieces can be increased, and a larger friction resistance can be generated to increase the preveling torque.

In particular, the friction piece is defined by the follower flank and the advance flank of the bolt when the bolt and the nut are screwed together by increasing the formation range of the friction piece and providing a space for preventing interference. In the same series of valley spaces, while deforming along the advancing flank on the front side in the circumferential direction of the friction piece, and below the follower flank on the rear side in the circumferential direction of the friction piece. It will be deformed along. As a result, it is possible to realize a new friction resistance application form in which resistance is applied to the screw thread of the bolt from both above and below.

The present invention has been able to provide a locking nut capable of increasing the pre-leveling torque.
Further, the present invention can properly engage the friction piece and the screw thread of the bolt even if the positional relationship between the friction piece and the nut main body is not as designed.

(A) The top view of the locking nut which concerns on embodiment of this invention. (B) The top view of the state which does not mount | wear with the friction ring of the locking nut. (C) Sectional view of the locking nut. Cross-sectional explanatory drawing which shows the transitional relationship between the locking nut and bolt. Cross-sectional explanatory drawing which shows the transitional relationship between the conventional locking nut and bolt. (A) The expanded view of the internal thread which shows the circumferential direction of the friction ring of the locking nut which concerns on embodiment of this invention. (B) The developed view of the conventional locking nut.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the nut 20 according to this embodiment includes a nut body 31 and a friction ring 21. The nut body 31 is suitably made of a metal having low elasticity such as steel or stainless steel, and the friction ring 21 is suitably made of metal having high elasticity such as spring steel. It can be changed as appropriate within the range that can be achieved.

The nut body 31 is formed with a female thread between the seat surface 32 and the upper surface 33 on the opposite side, and one or a plurality of threads (hereinafter, the thread of the nut body 31 is referred to as a female thread 34). And screwed with the bolt 11. The bolt 11 is a single thread or a plurality of threads (hereinafter, the thread of the bolt 11 is referred to as a male thread 12, and when it is not necessary to distinguish between the female thread 34 and the male thread 12, it is simply referred to as a thread. ). The female thread 34 includes an advance side flank 35 and a follower side flank 36 formed on both sides in the axial direction with a top portion 37 interposed therebetween, as in a normal nut, and a valley bottom 38 between the female thread 34. The male screw thread 12 includes an advance side flank 13 and a follower side flank 14 formed on both sides in the axial direction across the top portion 15, as in a normal bolt, and includes a valley bottom 16 between the male screw threads 12.
The specific shape of the thread can be changed as long as it is screwed together.

The friction ring 21 is attached to the upper surface 33 of the nut body 31. The friction ring 21 includes an annular fixing portion 22 and a friction piece 23 that protrudes toward the inner periphery thereof. The elasticity only needs to be in the friction piece 23, but it is more efficient in production if the entire friction ring 21 is made of a plate-like spring material.

In order to attach the friction ring 21, a caulking portion 39 is formed on the upper surface 33 of the nut body 31. The caulking portion 39 may be annular or may be provided intermittently in the circumferential direction. The attachment method is free. For example, if this type of friction nut is manufactured in accordance with a conventional method, the friction ring 21 is placed on the fixed reference surface 40 of the nut body 31 inside the caulking portion 39 before bending, and the caulking portion 39 is moved. The fixing portion 22 may be clamped between the fixed reference surface 40 and the caulking portion 39 by bending the inner peripheral side. The fixing means can be implemented by changing to other fixing methods and structures such as welding.

For the above attachment, the fixing portion 22 is formed in an annular shape, and the friction piece 23 projects into the screw hole of the nut body 31. As a result, when the bolt 11 and the nut 20 are screwed together, the friction piece 23 engages with the male thread 12. The inner diameter of the friction piece 23 can be changed on condition that it can be engaged with the male screw thread 12 to generate pre-leveling torque. It is appropriate to be. It should be noted that in relation to the female thread 34, it is appropriate that it is not less than the root diameter of the female thread 34 and not more than the thread diameter of the female thread 34.

Regarding the circumferential direction, in this example, the friction piece 23 protrudes from the fixed portion 22 over a range of about 350 degrees in the friction ring 21, and the transition portion 24 is formed over a range of about 10 degrees. It is considered that the friction effect increases as the formation range of the friction piece 23 in the circumferential direction increases. However, conventionally, when the angle exceeds 270 degrees, the interference with the male screw thread 12 is remarkable, and it has been considered impossible to exceed 280 degrees. On the other hand, in the present invention, even if the angle exceeds 270 degrees or 280 degrees, the interference with the male screw thread 12 can be eased and screwed, and the male screw thread 12 and the nut 20 are prevented from free rotation. A preveling torque can be generated, and a structure for realizing this will be described below.

In this type of conventional friction nut, the fixed reference surface 40 and the upper surface 33 of the nut body 31 are flush with each other and are set to the same height. On the other hand, in the present invention, the interference preventing space 41 is formed between the fixed reference surface 40 and the upper surface 33. In this embodiment, an interference preventing space 41 is formed by forming a concave portion by drilling an upper surface 33, which has been conventionally flush with the fixed reference surface 40, downward (seat surface 32 side). doing. However, the caulking portion 39 may be extended upward and the fixed reference surface 40 may be formed at a position higher than the upper surface 33, and means that are advantageous in processing can be selected and employed.

As shown in FIG. 4A, the positional relationship in the circumferential direction between the friction ring 21, the nut main body 31, and the bolt 11 is most preferably configured as follows. If the male screw thread 12 enters from below the transition part 24 and exits above the friction ring 21, it is not necessary to limit to the following.

First, a case where the interference prevention space 41 of FIG. 4B is not formed will be described. In the circumferential positional relationship between the transition portion 24 of the friction ring 21 and the external thread 12, the positions of both are set so that the tip of the external thread 12 enters the transition portion 24 of the friction ring 21 satisfactorily. . For this purpose, when the tip of the male thread 12 reaches the friction ring 21, the tip is positioned at the transition portion 24.

Here, in the case of FIG. 4B in which the interference prevention space 41 is not formed, the fixed reference surface 40 and the upper surface 33 of the nut body 31 are flush with each other (the same height). The position where the friction ring 21 is reached is the same as the position where the tip of the male thread 12 appears on the upper surface 33. Therefore, the rounded-up portion 42 that defines the position where the tip of the male screw thread 12 appears on the upper surface 33 may be located in the transition portion 24. In other words, on the upper surface 33 of the nut body 31, the raised portion 42 that defines the position of the tip where the female thread 34 appears is positioned so as to be located in the transition portion 24. Specifically, the female thread 34 is defined by the follower side flank 36, the top 37, and the advance side flank 35 from the upper surface 33 toward the seat surface 32, and the valley bottom 38 is located between the female thread 34 and the female thread 34. Therefore, the round-up portion 42 is positioned at the tip of the follower flank 36 (the boundary between the follower flank 36 and the valley bottom 38).

On the other hand, as shown in FIG. 4A, when the interference prevention space 41 is formed, the preferable position where the bolt 11 enters the transition portion 24 of the friction ring 21 does not change. As in the case of 4 (B), when the tip of the male thread 12 reaches the friction ring 21, the tip is positioned at the transition portion 24.

However, as shown in FIG. 4A, when the interference prevention space 41 is formed, the upper surface 33 is lower than the fixed reference surface 40 that defines the position of the friction ring 21 (close to the seat surface 32). Therefore, even if the tip of the male screw thread 12 appears on the upper surface 33, the tip of the male screw thread 12 does not reach the friction ring 21. The screw rotates by the height difference (for example, 1/3 pitch) between the fixed reference surface 40 and the upper surface 33, and the tip of the male screw thread 12 reaches the friction ring 21.

Therefore, in FIG. 4A of the present invention, the rounded-up portion 42 that defines the position at which the tip of the male screw thread 12 appears on the upper surface 33 has a height difference (for example, 1/3) between the fixed reference surface 40 and the upper surface 33. It suffices to arrange it at a position shifted from the transition portion 24 by the pitch). In other words, an imaginary line 44 that extends along the thread winding from the rounded-up portion 42 that defines the position of the tip where the female thread 34 appears on the upper surface 33 of the nut body 31 is formed in the transition portion 24. Place it so that it is located in Specifically, the imaginary line 44 extended along the screw winding from the rounded-up portion 42 located at the tip of the follower flank 36 (the boundary between the follower flank 36 and the valley bottom 38) is a transition portion 24. Arrange them so that they are inside.

When the friction ring 21 is arranged in the circumferential positional relationship as described above, the relationship among the friction ring 21, the bolt 11, and the nut body 31 will be described with reference to FIGS.
FIG. 2 shows the case according to the embodiment of the present invention (that is, the case of FIG. 4A in which an interference prevention space 41 is provided). The row shows a sectional view of the bolt 11 and the nut 20 at the same screwing angle in five positions (AA = about 0 degree, BB = 90 degree, in the position of FIG. (CC = 180 degrees, DD = 270 degrees, EE = about 360 degrees). In addition, in the column, cross-sectional views in a state in which the screwing angle of the bolt 11 with which the bolt 11 is screwed into the nut 20 are 0 degree, 90 degrees, 180 degrees, 270 degrees, 360 degrees, and 720 degrees are arranged. It is.
FIG. 3 shows a case according to a conventional form (that is, a case of FIG. 4B in which no interference prevention space 41 is provided). As in FIG. 3, the row shows a sectional view of the bolt 11 and the nut 20 at the same screwing angle at five positions (AA = about 0 degree, BB = 90 degree, CC). = 180 degrees, DD = 270 degrees, EE = about 360 degrees). Further, in the column, cross-sectional views in a state where the screwing angle of the bolt 11 with which the bolt 11 is screwed into the nut 20 are 0 degree, 90 degrees, 180 degrees, 270 degrees, and 360 degrees are arranged.

First, the case where the interference prevention space 41 is not provided (see FIG. 3) will be described. In this case, since the fixed reference surface 40 and the upper surface 33 are flush with each other (the same height in the axial direction), the friction piece 23 of the friction ring 21 and the screw thread interfere with each other, so that the bolt 11 and the nut are substantially. 20 cannot be screwed together.
As can be seen from the change in the column of FIG. 3, when the bolt 11 reaches the friction ring 21, the friction piece 23 of the friction ring 21 gradually rises along the advancing flank 13 of the male thread 12 and is lifted. become. At that time, when only the AA cross section is viewed, it gradually rises from 0 degrees to 360 degrees. And it turns out that this lifting state decreases along the spiral winding of a screw thread by changing to a DD section from an AA section. In this DD cross section (that is, a cross section at a position of 270 degrees in the circumferential direction from the AA cross section), the friction piece 23 is in contact with the upper surface 33, and the inner peripheral end thereof is the bottom 16 of the external thread 12. It is in a state of getting in.

However, in the EE cross section, the friction piece 23 interferes with the upper surface 33 and the external thread 12. This interference portion 43 is shown in black in FIG. More specifically, in the EE cross section, the friction piece 23 is originally guided by the follower flank 14 of the male thread 12 and is deformed so as to be positioned below the fixed reference plane 40. However, since the fixed reference surface 40 and the upper surface 33 are flush with each other, even if an attempt is made to deform below the fixed reference surface 40, the upper surface 33 is present and cannot be deformed downward. Interferes with the follower flank 14. In other words, the space in which the upper surface 33 is to be located is blocked by the fixed reference surface 40 and the male screw thread 12, and the friction piece 23 cannot exist. Therefore, at the stage where the screwing angle is relatively small, it is possible to recommend screwing by force by damaging the presence of tolerance between the bolt 11 and the nut body 31 or damaging the friction piece 23 or the male thread 12. As the angle of incidence increases, the friction piece 23 becomes sandwiched between the fixed reference surface 40 and the male screw thread 12, and the rotation of the screw does not proceed.

On the other hand, in the case of FIG. 2 according to the embodiment of the present invention, the upper surface 33 does not exist immediately below the fixed reference surface 40 and the interference prevention space 41 exists. Therefore, in the EE cross section, the friction piece 23 is guided by the follower flank 14 of the male thread 12 and can be deformed so as to be positioned below the fixed reference surface 40. As a result, the friction piece 23 is most significantly elastically deformed along the advancing flank 13 of the male screw thread 12 in the AA cross section, and the deformation becomes smaller as the angle advances in the circumferential direction, and the position of 270 degrees. In the cross section (DD cross section), the friction piece 23 has substantially the same height as the upper surface 33, and the inner peripheral end enters the valley bottom 16 of the male screw thread 12. In the present invention, since the inside of the interference prevention space 41 exists, the friction piece 23 has the upper surface 33 in the EE cross section (that is, the cross section at the position of 350 degrees on the side flank from the AA cross section). It can be elastically deformed downward. As a result, the friction piece 23 comes to follow the follower flank 14 of the male screw thread 12. Accordingly, as can be seen from the AA cross section at the screwing angle of 720 degrees which is the lowermost row in FIG. 2, the friction piece 23 includes the advance flank 13 and the follower flank 13 of the male thread 12. 14, and is elastically deformed along the advancing flank 13 on the front side in the circumferential direction of the friction piece 23 (cross section AA to CC), and is circumferentially The rear side (EE cross section) is deformed along the lower side of the follower flank 14. As a result, the rotation of the screw can be advanced, and frictional resistance can be applied from both the upper and lower sides of the male thread 12, so that a larger preveling torque can be generated than in the prior art.

The design may cause the above-described interference when the formation range of the friction piece 23 exceeds a certain range.
The angle X of this constant formation range is obtained by X = (1−b / p) × 360 (where b = the axial length of the valley bottom 38 between the female thread 34 in the nut body 31. p = the female thread 1 pitch.)

For example, in each of the above-described drawings, the axial length of the valley bottom 38 uses the nut body 31 with a 1/4 pitch, and the friction piece 23 falls within a range exceeding X = 3/4 × 360 = 270 degrees. If formed, interference may occur. Actually, since a screw tolerance is added to this, if the friction piece 23 is formed in a range exceeding about 280 degrees by adding about 10 degrees, interference may occur.

The present invention can be implemented with various modifications. For example, although the transition part 24 is implemented as having a width in the circumferential direction, it may be a linear notch having no substantial area. Therefore, in this case, the friction piece 23 has an angle of about the entire circumference (theoretically less than 360 degrees). Furthermore, even if it is 360 degrees or more and the front end and the rear end of the friction piece 23 overlap (whether or not they contact), the front end of the male screw thread 12 enters between the front end and the rear end. If you can, you can do it. In particular, by forming the friction ring 21 in a three-dimensional shape such as a spiral shape instead of a flat plate shape, the male thread 12 is formed between the front end and the rear end of the overlapping friction pieces 23. The tip of the can be invaded and transferred.

In the above-described example, the friction piece 23 is continuous in the circumferential direction, but may be divided into a plurality of pieces in the circumferential direction. In the above example, the friction piece 23 may be continuous at 350 degrees. For example, the friction piece 23 is divided into about 65 degrees, for example, and divided into about 5 degrees therebetween. It can also be. Thus, even when the friction piece 23 is divided into a plurality of pieces in the circumferential direction, the formation range between the frontmost friction piece 23 and the last friction piece 23 in the circumferential direction is 270 degrees (over 280 degrees in consideration of tolerances). In this case, the above-described interference problem may occur, but the present invention can suppress such a risk.

In the previous example, the interference prevention space 41 was formed on the entire circumference, but at least in the circumferential range in which the above-described interference occurs (the range in which the friction piece 23 is deformed below the fixed reference surface 40). What is necessary is just to form. Specifically, the formation range of the interference prevention space 41 in the circumferential direction can be set to be equal to or greater than Y degrees obtained by Y = b / p × 360 (provided that b = between the female thread 34 in the nut body 31). The axial length of the valley bottom 38. p = one pitch of the female thread.) For example, in each of the above-mentioned drawings, the axial length of the valley bottom 38 uses the nut body 31 having a 1/4 pitch, and the friction piece 23 falls within a range exceeding X = 1/4 × 360 = 90 degrees. It can be considered that the occurrence of interference can be eliminated by forming.

The axial length of the interference prevention space 41 varies depending on the protruding length of the interference prevention space 41 and the formation range in the circumferential direction. However, the axial length of the female screw thread is greater than the axial length of the valley bottom 38 of the female screw. An axial length of 34 1/3 pitch or more is sufficient. Of course, the length may be less than the axial length of the valley bottom 38 of the female screw provided that the above-described interference can be avoided. Theoretically, no matter how large the axial length is, there is no problem from the viewpoint of preventing interference. However, in general, it is often desirable that the nut 20 be small if it has the same performance. There is no need to increase this value unnecessarily. More specifically, for example, when the axial length of the valley bottom 38 is ¼, a stable product can be made by placing an interval of about ３ with a slight margin.

Further, the interference prevention space 41 is implemented as a plane orthogonal to the axial direction. However, the interference prevention space 41 can be implemented as an inclined surface or curved surface inclined downward from the fixed reference surface 40 toward the inner peripheral side. The concrete shape can be variously changed and implemented on condition that a space capable of deforming can be secured.

The present invention can find one effect in suppressing the above-mentioned interference that occurs when the circumferential range of the friction piece 23 exceeds 270 degrees (280 degrees when an intersection is added). Even if the range in the circumferential direction is 270 degrees (or 280 degrees when crossing is added) or less, it can be implemented. In this case, if there is no conventional interference prevention space, the above-described interference may occur unless the position of the transition portion 24 of the friction ring 21 is accurately set. Thus, even when the accuracy of the position is lowered, the possibility of causing interference can be reduced, and the occurrence of a defect rate can be suppressed.

11 Bolt 12 Male thread 13 Leading flank 14 Trailing flank 15 Top 16 Valley bottom 20 Nut 21 Friction ring 22 Fixing part 23 Friction piece 24 Transition part 31 Nut body 32 Seat surface 33 Top face 34 Female thread 35 Leading side flank 36 Trailing side flank 37 Top part 38 Valley bottom 39 Caulking part 40 Fixed reference plane 41 Interference prevention space 42 Round-up part 43 Interference part 44 Virtual line

Claims (5)

A nut body having a female screw and a seating surface, and a friction piece for generating a preveling torque fixed to the upper surface of the nut body facing the seating surface,
In the locking nut that causes the male screw of the bolt to enter from the transition portion without the friction piece, and generates the pre-torque torque by engaging with the male screw that the friction piece has entered and elastically deforming,
An anti-loosening nut characterized in that an interference preventing space for preventing interference between the friction piece and the male screw is provided in an axial direction between the upper surface and the friction piece. In the screwed state with the bolt, the friction piece is located in the same series of valley spaces defined by the follower flank and the advance flank of the bolt,
The friction piece is deformed along the advance side flank on the front side in the circumferential direction of the friction piece, and is deformed along the bottom side of the follower flank on the rear side in the circumferential direction of the friction piece. The locking nut according to claim 1, wherein: 3. The locking nut according to claim 1, wherein the friction piece is formed over a range in the circumferential direction equal to or greater than X degrees of the following formula 1. 3.
[Formula 1] X = (1-b / p) × 360
Where b = the axial length of the bottom of the female thread of the nut body. p = one pitch of female thread. The loosening prevention nut according to any one of claims 1 to 3, wherein the interference preventing space has an axial length that is equal to or greater than an axial length of a valley bottom of the female screw. The interference prevention space according to any one of claims 1 to 4, wherein the interference prevention space is formed over a range in a circumferential direction equal to or less than Y degrees of the following equation (2).
[Formula 2] Y = b / p × 360
Where b = the axial length of the bottom of the female thread of the nut body. p = one pitch of female thread.

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