JP4418899B2 - Locking nut - Google Patents

Description

  The present invention relates to a locking nut used for a fastening bolt or the like.

  As the locking nut, there is generally known a resistance increasing type that increases resistance against the return rotation of the nut, such as a pre-leveling torque nut or a locking nut.

  Preveling torque type nuts increase the resistance by causing interference between the male screw and the female screw from the beginning, but compared with the locking type nut that causes interference between the male screw and the female screw by tightening the nut. A large resistance could not be obtained, and there was a limit to the loosening prevention effect. In addition, a double nut, which is a representative example of a locking nut, requires advanced technology for torque management and the like in order to perform a reliable tightening operation.

  For this reason, a locking nut 91 as shown in FIG. 4 is known as a configuration that facilitates the tightening operation. The locking nut 91 includes an upper nut portion 94 and a lower nut portion 95 that have fitting portions opposed to each other and are screwed into the bolt 92 in two upper and lower stages, and the fitting portion of the upper nut portion 94+ is a shaft center. Is formed in a conical hole shape that coincides with the screw hole center, and the fitting portion of the lower nut portion 95 is formed in a truncated cone shape in which the shaft center is arranged eccentrically with respect to the screw hole center.

  However, in this fastener 91, the upper nut portion 94 and the lower nut portion 95 are separated from each other, and when tightening, the lower nut portion 95 is screwed into the bolt 92 and then the upper nut portion. Since it is necessary to screw 94 into the bolt 92, the tightening work is complicated, and the management of the parts is also troublesome.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a locking nut that can be easily tightened and can provide an excellent locking effect.

  The object of the present invention is to provide an upper nut in which a small-diameter female screw portion is formed on one side of the inner peripheral surface and a large-diameter female screw portion having a larger diameter than the small-diameter female screw portion is formed on the other side, and the large-diameter female screw portion A lower nut and a middle nut screwed into the small-diameter female screw portion, and the upper nut is formed such that pitches of the small-diameter female screw portion and the large-diameter female screw portion are different from each other. The lower nut and the middle nut are arranged so that their axial centers coincide with each other through engagement means, and the relative rotation is restricted, and bolts are arranged on the respective inner peripheral surfaces. This is achieved by a locking nut having an internally threaded portion that is screwed together.

  In this locking nut, the upper nut can be formed such that the pitch of the small-diameter female screw portion is larger than the pitch of the large-diameter female screw portion.

  The spiral direction of the small-diameter female screw portion and the large-diameter female screw portion in the upper nut is preferably opposite to the spiral direction of the female screw portion on the inner peripheral surfaces of the lower nut and the intermediate nut.

  Moreover, the said engaging part can be comprised from the protrusion provided in any one of the said lower nut and the inside nut, and the notch part formed in the other. In this case, it is preferable to provide a spacer on the bottom surface of the notch.

  Moreover, it is preferable that the said upper nut and a lower nut have a holding part in an outer peripheral surface.

  According to the locking nut according to the present invention, it is possible to easily perform a tightening operation and to obtain an excellent locking effect.

  Hereinafter, actual forms of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side sectional view of a locking nut 1 according to an embodiment of the present invention.

  The locking nut 1 includes an upper nut 10, a lower nut 20, and an intermediate nut 30. These materials can be appropriately selected from ordinary steel, stainless steel, high-tensile steel, non-ferrous metal, and the like.

  The upper nut 10 is formed with an upper gripping portion 18 having a predetermined two-surface width on one side of the outer peripheral surface. On the inner peripheral surface of the upper nut 10, a small-diameter female screw portion 10a is formed on one side, and a large-diameter female screw portion 10b having a diameter larger than that of the small-diameter female screw portion 10a is formed on the other side. The stopper 19 which consists of is formed. The small-diameter female screw portion 10a and the large-diameter female screw portion 10b have the same screw spiral direction, and are left-handed in this embodiment. Further, the pitch of the small-diameter female screw portion 10a is different from the pitch of the large-diameter female screw portion 10b, and in this embodiment, the pitch of the small-diameter female screw portion 10a is formed to be larger.

  As for the lower nut 20, the internal thread part 25 is formed in the internal peripheral surface. The spiral direction of the female screw portion 25 is opposite to the spiral direction of the small-diameter female screw portion 10a and the large-diameter female screw portion 10b in the upper nut 10, and is a right-hand screw in this embodiment. On one side of the outer peripheral surface of the lower nut 20, a male screw portion 26 that is screwed into the large-diameter female screw portion 10b of the upper nut 10 at the same pitch is formed. Further, on the other side of the outer peripheral surface of the lower nut 20, a lower gripping portion 27 formed with a substantially two-surface width as the upper gripping portion 18 of the upper nut 10 is formed.

  A cutout portion 22 that engages with a protrusion 32 described later is formed on one end face of the lower nut 20, and a spacer 23 is provided on the bottom surface of the cutout portion 22. The spacer 23 can be formed by applying and curing an adhesive such as an epoxy resin.

  The inner nut 30 is formed with an inner thread surface 35 having the same diameter and pitch as the inner thread portion 25 of the lower nut 20. Bolts 100 are screwed into the inner thread portions 25 and 35 at the same pitch. Is done. A male screw portion 36 is formed on the outer peripheral surface of the intermediate nut 30 and is screwed into the small diameter female screw portion 10a of the upper nut 10 at the same pitch. A projecting portion 32 that engages with the notched portion 22 of the lower nut 20 is provided at the lower end portion of the intermediate nut 30 so as to protrude in the axial direction, and the notched portion 22 and the projecting portion 32 constitute an engaging portion. ing.

  The above-described upper nut 10, lower nut 20, and middle nut 30 are assembled as follows.

  First, the intermediate nut 30 and the lower nut 20 are overlapped so that the protrusion 32 and the notch 22 are engaged, and then the small-diameter female screw portion 10a and the large-diameter female screw portion 10b of the upper nut 10 are respectively connected to the intermediate nut. The screw 30 is screwed into the male screw portion 36 and the male screw portion 26 of the lower nut 20. The rotation of the middle nut 30 and the lower nut 20 is mutually restricted by the protrusion 32 and the notch 22, and the pitch of the small-diameter female screw portion 10a is larger than the pitch of the large-diameter female screw portion 10b. As the screw is screwed in, the distance between the middle nut 30 and the lower nut 20 gradually increases. For example, when the pitch of the small-diameter female screw portion 10a and the pitch of the large-diameter female screw portion 10b are 1.5 mm and 1 mm, respectively, when the upper nut 10 rotates once, the middle nut 30 and the lower nut 20 It moves 1.5 mm and 1 mm relative to the nut 10. As a result, the distance d between the middle nut 30 and the lower nut 20 increases by the difference (0.5 mm) in the amount of movement between the two.

  Thus, by screwing the upper nut 10 until the stopper 19 comes into contact with the upper end of the lower nut 20, the locking nut 1 in which the upper nut 10, the lower nut 20, and the middle nut 30 are integrated is assembled. As described above, the locking nut 1 of the present embodiment can be handled as a single component in which the upper nut 10, the lower nut 20, and the intermediate nut 30 are integrated. It can be carried out.

  Then, the spacer 23 is formed by applying an adhesive to the lower surface of the notch 22 and curing it. Thus, by forming the spacer 23, even if the upper nut 10 is rotated in the reverse direction, the lower nut 20 and the intermediate nut 30 do not return to the original contact state. And it can prevent that the inside nut 30 isolate | separates unexpectedly.

  Next, a method for performing a tightening operation using the locking nut 1 configured as described above will be described.

  First, the locking nut 1 configured as shown in FIG. 1 is screwed into the bolt 100 inserted into the bolt hole 110 of the fastened member 105 from the lower nut 20 side as shown in FIG. Tighten while turning clockwise with a wrench. As a result, the lower nut 20 and the middle nut 30 are screwed into the bolt 100. Thus, the lower nut 20 is tightened until it comes into contact with the fastened member 105, and is tightened with a predetermined torque.

  Next, the upper gripping portion 18 is turned clockwise with a torque wrench or the like. Since the inner peripheral surface of the upper nut 10 is a left-hand thread, the upper nut 10 moves upward relative to the middle nut 30 and the lower nut 20 when rotated to the right. As described above, since the pitch of the small-diameter female screw portion 10a is larger than the pitch of the large-diameter female screw portion 10b, the distance d between the middle nut 30 and the lower nut 20 gradually decreases as the upper nut 10 rotates. As a result, the screwed portion of the bolt 100 receives a pressing force in the direction indicated by the arrow A from the middle nut 30, and receives a pressing force in the direction indicated by the arrow B from the lower nut 20. Directional force will act (FIG. 3). Thus, by tightening the upper nut 10 with a predetermined torque, a sufficient locking force acts between the bolt 100 and the locking nut 1 and an excellent locking effect can be obtained.

  Further, as in the present embodiment, the spiral direction of the female screw portions 25 and 35 in the lower nut 20 and the intermediate nut 30 is opposite to the spiral direction of the small-diameter female screw portion 10a and the large-diameter female screw portion 10b in the upper nut 10. By doing so, the tightening direction of the lower nut 20 and the tightening direction of the upper nut 10 can be matched, and the tightening operation can be facilitated.

  When removing the locking nut 1 from the bolt 100, the procedure opposite to the tightening operation described above is performed. That is, the upper nut 10 is rotated counterclockwise until the stopper 19 comes into contact with the lower nut 20, the locking force applied to the bolt 100 by the lower nut 20 and the intermediate nut 30 is released, and then the lower nut 20 is rotated counterclockwise. The locking nut 1 can be removed from the bolt 100.

  As mentioned above, although one Embodiment of this invention was explained in full detail, the specific aspect of this invention is not limited to the said embodiment. For example, in the present embodiment, the upper nut 10 is formed such that the pitch of the small-diameter female screw portion 10a is larger than the pitch of the large-diameter female screw portion 10b, but the pitch of the small-diameter female screw portion 10a is large-diameter female screw. You may form so that it may become smaller than the pitch of the part 10b. In this configuration, when the upper nut 10 is tightened, the distance between the lower nut 20 and the intermediate nut 30 is increased, so that a force in the tensile direction acts on the bolt 100. Therefore, even in this case, a sufficient locking force can be applied between the bolt 100 and the locking nut 1.

  In the present embodiment, the spiral direction of the female screw portions 25 and 35 in the lower nut 20 and the intermediate nut 30 is opposite to the spiral direction of the small-diameter female screw portion 10a and the large-diameter female screw portion 10b in the upper nut 10. However, they can also be in the same direction.

  In the present embodiment, the notch 22 is formed in the lower nut 20 and the protrusion 32 is formed in the middle nut 30 to constitute the engaging portion, but the protrusion is formed in the lower nut 20. However, a cutout portion may be formed in the inner nut 30.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to this embodiment.

  A loosening prevention nut 1 shown in FIG. 1 was used in the example, and only the lower nut 20 was used in the comparative example, and a vibration loosening test based on the NAS (National Aerospace Standard) 3350 standard was performed. In both the examples and the comparative examples, the lower nut 20 was M16 × 2, and the tightening torque of each nut was set as shown in Table 1 and the test was performed.

表１から明らかなように、実施例は比較例より耐震時間が長く、優れた緩み止め効果が得られることを確認した。

As is clear from Table 1, it was confirmed that the examples had a longer seismic resistance time than the comparative examples, and an excellent locking effect was obtained.

It is side surface sectional drawing of the locking nut which concerns on one Embodiment of this invention. It is sectional drawing which shows the state in the middle of clamping of the locking nut shown in FIG. It is sectional drawing which shows the state after the fastening of the locking nut shown in FIG. It is sectional drawing which shows the conventional fastener.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Locking nut 10 Upper nut 10a Small-diameter internal thread part 10b Large-diameter internal thread part 18 Upper side grip part 20 Lower nut 22 Notch part 23 Spacer 25 Internal thread part 26 Male thread part 27 Lower side grip part 30 Middle nut 32 Protrusion part 35 Internal thread part 36 Male thread Part 100 Bolt 105 Fastened member 110 Bolt hole

Claims (5)

An upper nut having a small-diameter female screw portion formed on one side of the inner peripheral surface and a large-diameter female screw portion having a larger diameter than the small-diameter female screw portion on the other side;
A lower nut screwed into the large-diameter female thread portion;
An intermediate nut to be screwed into the small diameter female thread portion,
The upper nut is formed such that the pitches of the small-diameter female screw portion and the large-diameter female screw portion are different from each other,
The lower nut and the middle nut are engaged with each other through an engagement means so that the axes coincide with each other in a state in which relative rotation is restricted, and a bolt is screwed on each inner peripheral surface. A locking nut having a female threaded portion.   2. The locking nut according to claim 1, wherein the upper nut is formed such that a pitch of the small-diameter female screw portion is larger than a pitch of the large-diameter female screw portion.   The loosening prevention according to claim 1 or 2, wherein the spiral direction of the small-diameter female screw portion and the large-diameter female screw portion in the upper nut is opposite to the spiral direction of the female screw portion on the inner peripheral surface of the lower nut and the middle nut. nut. The engaging portion is composed of a protrusion provided on one of the lower nut and the intermediate nut, and a notch formed on the other,
The locking nut according to any one of claims 1 to 3, wherein the notch has a spacer on the bottom surface. The said upper nut and lower nut are locking nuts in any one of Claim 1 to 4 which has a holding part in an outer peripheral surface.

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