JP6529671B2 - Locking prevention nut and fastening method - Google Patents

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a loosening prevention nut and a fastening method, which are tightened on a mating member such as a bolt and prevented from loosening due to return rotation caused by vibration or the like.

  Conventionally, bolts and nuts are used as fasteners to secure various building components or machine parts. In bolts and nuts used as fastening parts, the nuts may rotate in the return direction due to slippage due to vibration or rotation of the parts to be fastened. As a result, the nut returns and loosens due to rotation, which causes a problem of reduction in the fastening effect.

  In order to prevent the looseness due to the return rotation, various bolt and nut structures have been proposed (see Patent Documents 1 and 2).

  For example, in the technique described in Patent Document 1, when the nut is tightened to a bolt, the tip of a projection formed on the bearing surface of the nut bites into the male screw portion of the bolt. And the protrusion which bited in the external thread part is crushed, and the locking effect is heightened by the rise of the frictional force taken in by the external thread part of a bolt.

  Further, in the technique described in Patent Document 2, a part of the female screw part of the nut is broken by the broken part of the male screw part of the bolt. Thus, the nut screwed into the bolt does not come loose.

JP-A-11-315820 Japanese Patent Application Laid-Open No. 62-86409

  In the technique described in Patent Document 1, a part of the nut is deformed to contribute to the improvement of the frictional force with respect to the bolt to be screwed, thereby preventing the loosening. However, the improvement of the frictional force is used as a method until it gets tired. For this reason, when a to-be-fastened member receives a vibration, or when a to-be-fastened member rotates etc., the loosening by the return rotation which made the slip of a fastening part a cause can not be prevented.

  In the technique described in Patent Document 2, the external thread portion of the bolt has a breaking portion, and loosening is prevented by breaking a portion of the internal thread portion of the nut. However, the bolt is not a structure that can improve the loosening of a nut having an external thread.

  The present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to provide a loosening preventing nut and a fastening method which more securely prevent loosening due to return rotation of the nut.

The loosening prevention nut according to the present invention is continuous from the opening opened at one end face, and is continuous from the female screw portion screwed with the external thread of the mating member and the opening opened at the other end face, A hole having a diameter smaller than the external diameter of the external thread of the external thread of the member and larger than the diameter of the external thread valley, and attached from the side of the internal thread to the mating member The screw thread of the male screw portion of the mating member is plastically deformed at the hole portion when it is tightened and rotated with respect to the mating member to be engaged .

  In the fastening method according to the present invention, the mating member is continuous from the opening opened at one end face, and is continuous from the female screw portion screwed to the male screw portion of the mating member and the opening opened at the other end face And a hole having a diameter smaller than the external diameter of the external thread of the external thread and a diameter larger than the diameter of the external thread from the side of the internal thread relative to the counter member. The screw thread of the male screw portion of the mating member is plastically deformed at the hole when the screw is tightened and rotated with respect to the mating member to be attached and screwed.

  According to the loosening prevention nut and the fastening method of the present invention, the loosening prevention nut having the female screw portion and the hole portion is attached to the mating member from the female screw portion side, and is screwed onto the mating member At the time of tightening and rotating, the thread of the male screw of the mating member is plastically deformed at the hole. The plastically deformed external thread does not screw into the internal thread of the loosening prevention nut. For this reason, the loosening prevention nut does not rotate back in the backward direction of the plastically deformed external thread. Therefore, the loosening prevention nut can prevent the loosening due to the return rotation more firmly.

It is sectional drawing which shows the loosening prevention nut which concerns on Embodiment 1 of this invention. It is a figure which shows the state by which the loosening prevention nut which concerns on Embodiment 1 of this invention is tightened to a volt | bolt. It is a figure which shows the state which the internal thread part of the loosening prevention nut which concerns on Embodiment 1 of this invention screw-engages with the external thread part of a volt | bolt. It is a figure which shows the state which the hole part of the loosening prevention nut which concerns on Embodiment 1 of this invention plastically deforms the external thread part of a volt | bolt. It is a partially expanded view which shows the external thread part of the volt | bolt which concerns on Embodiment 1 of this invention. It is a partially developed view which shows the boundary which the external thread part of the volt | bolt based on Embodiment 1 of this invention plastically deformed. It is sectional drawing which shows the loosening prevention nut which concerns on Embodiment 2 of this invention.

Hereinafter, embodiments of the present invention will be described based on the drawings.
In the drawings, the same reference numerals denote the same or corresponding parts, which are common to the whole text of the specification.
Furthermore, the form of the component shown in the specification full text is an illustration to the last, and is not limited to these descriptions.

Embodiment 1
A loosening prevention nut 100 according to a first embodiment of the present invention will be described.
FIG. 1 is a cross-sectional view showing a loosening prevention nut 100 according to a first embodiment of the present invention. FIG. 2 is a view showing a state in which the loosening prevention nut 100 according to Embodiment 1 of the present invention is tightened to the bolt 40. As shown in FIG.
The loosening prevention nut 100 shown in FIG. 1 includes a female screw 20 and a hole 30.
The loosening prevention nut 100 has a general outer shape such as a hexagonal, octagonal or tetragonal shape.

  As shown in FIG. 2, the female screw portion 20 is continuous from an opening opened in one end face 21 of the side attached to the bolt 40 which is a mating member, and is screwed into the male screw portion 41 of the bolt 40. The female screw portion 20 is formed with a thread 22 having a hook height according to a predetermined lead angle and pitch.

The hole 30 is continuous from an opening opened at the other end face 31 opposite to the side attached to the bolt 40. The hole diameter of the hole 30 is smaller than the external diameter 42 of the external thread of the external thread 41 of the bolt 40 and larger than the external diameter 43 of the external thread.
Specifically, the hole 30 plastically deforms the screw thread 44 of the male screw portion 41 of the bolt 40 so that the screw groove 45 of the male screw portion 41 of the bolt 40 is embedded, and the male screw of the bolt 40 becomes the outer peripheral surface 46 The hole diameter is such that the portion 41 has a diameter larger than the inner diameter 23 of the female screw portion 20.
The hole diameter of the holes 30 is the same hole diameter dimension extending in the axial direction at the same center line.

  The female screw portion 20 and the hole 30 have a center line extending in the axial direction coincident with each other. Further, the female screw portion 20 and the hole portion 30 are directly and continuously formed inside the loosening prevention nut 100.

The loosening prevention nut 100 configured as described above has the hole 30 continuously with the female screw 20 in the reverse direction opposite to the tightening and rotating direction. When the loosening prevention nut 100 is tightened and rotated in the rotational direction, the hole 30 squeezes the screw thread 44 of the male screw 41 of the bolt 40 and does not screw with the female screw 20 of the loosening prevention nut 100 Let
The loosening prevention nut 100 has a hole 30 continuous with the female screw 20. For this reason, when the loosening prevention nut 100 is tightened and rotated in the tightening rotational direction by the user using a jig, a large force is necessary for the hole 30 to plastically deform the screw thread 44 of the male screw portion 41 of the bolt 40 is there. However, when the user plastically deforms the thread 44 of the male screw portion 41 of the bolt 40 with a large force, the plastically deformed portion of the male screw portion 41 of the bolt 40 is difficult to deform again.

  FIG. 3 is a view showing a state in which the female screw portion of the loosening prevention nut according to the first embodiment of the present invention is screwed to the male screw portion of the bolt. FIG. 4 is a view showing a state in which the hole portion of the loosening prevention nut according to the first embodiment of the present invention plastically deforms the male screw portion of the bolt.

  First, as shown in FIG. 2, a female member opened at one end face 21 of the loosening prevention nut 100 with respect to the bolt 40 having a male screw portion 41 which protrudes upward through the mounting hole 51 of the member 50 to be fastened. The screw portion 20 is screwed.

  Next, the loosening prevention nut 100 is tightened and rotated in the tightening and rotating direction by the user using a jig, and advances toward the to-be-fastened member 50 side. As shown in FIG. 3, when the loosening prevention nut 100 is screwed into the bolt 40, the hole 30 of the loosening prevention nut 100 contacts the tip of the male screw portion 41 of the bolt 40.

  When the anti-loosening nut 100 is further tightened, the hole 30 of the anti-loosening nut 100 does not deform plastically and tries to move in the rotational direction. At this time, the hole diameter of the hole 30 of the loosening prevention nut 100 is smaller than the outer diameter 42 of the male screw 41 of the bolt 40 to be screwed. Therefore, as shown in FIG. 4, the hole 30 plastically deforms the thread 44 of the male screw 41 of the bolt 40 so as to be embedded in the screw groove 45. The outer diameter of the outer circumferential surface 46 of the externally threaded portion 41 of the plastically deformed bolt 40 substantially matches the hole diameter of the hole 30 of the loosening prevention nut 100.

  FIG. 5 is a partially developed view showing the male screw portion 41 of the bolt 40 according to the first embodiment of the present invention. FIG. 6 is a partially developed view showing a boundary 47 where the external thread portion 41 of the bolt 40 according to Embodiment 1 of the present invention is plastically deformed.

  As shown in FIG. 5, before plastic deformation, the screw thread 44 and the screw groove 45 of the male screw portion 41 of the bolt 40 are clearly separated so that they can be screwed to the female screw portion 20 of the loosening prevention nut 100.

  On the other hand, as shown in FIG. 6, when the loosening prevention nut 100 advances in the tightening and rotating direction and the hole 30 plastically deforms the thread 44 of the male screw 41 of the bolt 40, the male screw 41 of the bolt 40 is The screw thread 44 and the screw groove 45 form an outer circumferential surface 46 of substantially constant diameter. That is, as shown by the arrows in FIG. 4, the thread groove 45 of the male screw portion 41 of the bolt 40 which is plastically deformed by passing through the hole 30 of the loosening prevention nut 100 is buried in the plastically deformed thread 44. Therefore, the female screw portion 20 of the loosening prevention nut 100 can not be screwed with the male screw portion 41 of the plastically deformed bolt 40.

  Thus, after the loosening prevention nut 100 is tightened, the female screw portion 20 of the loosening prevention nut 100 and the outer peripheral surface 46 which is a portion of the plastically deformed bolt 40 do not engage with each other. Therefore, the loosening prevention nut 100 can not return and rotate in the direction opposite to the tightening rotational direction of the bolt 40. That is, the loosening prevention nut 100 does not cause loosening due to return rotation even when receiving slippage of the fastening portion due to vibration or rotation of the member 50 to be fastened.

  Further, even if the plastically deformed outer peripheral surface 46 of the bolt 40 tries to deform in the loosening direction due to the return rotation, the plastically deformed portion of the bolt 40 is continuous from the location of the boundary 47. Therefore, the looseness due to the return rotation of the loosening prevention nut 100 is firmly prevented by the continuous plastically deformed outer peripheral surface 46 of the bolt 40. Alternatively, even if a part of the outer peripheral surface 46 is deformed from the boundary 47, the outer peripheral surface 46 continues from that part. Thereby, the loosening due to the return rotation of the anti-loosening nut 100 is limited to a minimum. Therefore, it is possible to prevent the loosening due to the return rotation of the loosening prevention nut 100 from becoming worse.

According to the first embodiment, the loosening prevention nut 100 is provided with the female screw portion 20 which is continuous from the opening portion opened at the one end face 21 and which is screwed to the male screw portion 41 of the bolt 40. The loosening prevention nut 100 is continuous with an opening opened at the other end face 31 and includes a hole 30 having a diameter smaller than the external thread diameter 42 of the external thread 41 of the bolt 40.
According to this configuration, the loosening prevention nut 100 having the female screw portion 20 and the hole portion 30 is attached to the bolt 40 from the female screw portion 20 side, and is tightened and rotated with respect to the screw 40 to be screwed At this time, the thread 44 of the male screw 41 of the bolt 40 is plastically deformed at the hole 30. The plastically deformed external thread portion 41 is not screwed into the internal thread portion 20 of the loosening prevention nut 100. For this reason, the loosening prevention nut 100 does not rotate back in the backward direction of the plastically deformed external thread portion 41. Therefore, the loosening prevention nut 100 can prevent the loosening due to the return rotation more firmly.

The centerline of the female screw 20 and the hole 30 coincide with each other.
According to this configuration, when the loosening prevention nut 100 is tightened and rotated with respect to the bolt 40 to be screwed, the thread 44 of the male screw portion 41 of the bolt 40 can be plastically deformed in the hole 30.

The female screw 20 and the hole 30 are formed continuously.
According to this configuration, a large force is required for the male screw 41 of the bolt 40 to enter the hole 30 when the loosening prevention nut 100 is tightened and rotated by the user using a jig. However, when the user plastically deforms the thread 44 of the male screw portion 41 of the bolt 40 with a large force, it is difficult for the plastically deformed portion to be deformed again. Therefore, the loosening prevention nut 100 can prevent the loosening due to the return rotation more firmly.

The loosening prevention nut 100 is attached to the bolt 40 from the female screw 20 side, and when it is tightened and rotated with respect to the screw 40 to be screwed, the screw thread 44 of the male screw 41 of the bolt 40 Plastically deform.
According to this configuration, the plastically deformed external thread portion 41 is not screwed into the internal thread portion 20 of the loosening prevention nut 100. For this reason, the loosening prevention nut 100 does not rotate back in the backward direction of the plastically deformed external thread portion 41. Therefore, the loosening prevention nut 100 can prevent the loosening due to the return rotation more firmly.

In the hole 30, the thread 44 of the male screw 41 of the bolt 40 is plastically deformed so that the screw groove 45 of the male screw 41 of the bolt 40 is embedded, and the male screw 41 of the bolt 40 becomes the inner diameter 23 of the female screw 20. It is a hole diameter configured to be larger than the diameter.
According to this configuration, the plastically deformed external thread portion 41 is deformed to the outer diameter dimension which is the outer peripheral surface 46 which is not screwed to the internal thread portion 20 of the loosening prevention nut 100.

The loosening prevention nut 100 is provided with a female screw portion 20 which is continuous from an opening opened at one end face 21 and which is screwed to the male screw portion 41 of the bolt 40. The loosening prevention nut 100 is continuous with an opening opened at the other end face 31 and includes a hole 30 having a diameter smaller than the external thread diameter 42 of the external thread 41 of the bolt 40. In the fastening method, the anti-loosening nut 100 is attached to the bolt 40 from the female screw 20 side. In the fastening method, the thread 44 of the male screw portion 41 of the bolt 40 is plastically deformed at the hole 30 when it is tightened and rotated with respect to the bolt 40 to be screwed.
According to this configuration, the loosening prevention nut 100 has the internal thread 20 screwed with the bolt 40. Therefore, when the loosening prevention nut 100 is tightened to the bolt 40, the loosening prevention nut 100 can be rotated in the advancing direction which is the tightening rotational direction. Further, the loosening prevention nut 100 has a hole 30 continuously to the female screw 20. Then, when the screw 40 is tightened and rotated, the screw thread 44 of the male screw portion 41 of the bolt 40 is plastically deformed in the hole 30. Therefore, the bolt 40 is plastically deformed so as not to engage with the female screw portion 20 of the loosening prevention nut 100. Therefore, the loosening prevention nut 100 can not rotate in the reverse direction which is the return rotation direction.
In particular, the force to return and rotate due to the vibration of the fastened building component or the rotation of the mechanical component is weaker than the force that plastically deforms the thread 44 of the male screw 41 of the bolt 40 at the hole 30. Therefore, the loosening prevention nut 100 does not return to rotate and deform the outer peripheral surface 46 of the male screw portion 41 of the bolt 40 again. Therefore, the loosening prevention nut 100 can prevent the loosening due to the return rotation caused by the vibration of the fastened building component or the rotation of the mechanical component more firmly.

Second Embodiment
FIG. 7 is a cross-sectional view showing a loosening prevention nut 200 according to a second embodiment of the present invention. In the second embodiment, points different from the first embodiment will be mainly described.

The loosening prevention nut 200 shown in FIG. 7 includes a female screw portion 20, a tapered portion 60, and a hole 30.
The female screw portion 20, the tapered portion 60, and the hole portion 30 have central lines extending in the axial direction coincide with each other.
In addition, the female screw portion 20 and the hole portion 30 are continuously formed via the taper portion 60.

The tapered portion 60 has a truncated cone-shaped inner circumferential surface whose diameter decreases from the female screw portion 20 toward the hole 30.
The female screw portion 20 and the hole 30 have the same configuration as that of the first embodiment.

The loosening prevention nut 200 configured as described above has a tapered portion 60 continuously with the female screw portion 20 in the reverse direction opposite to the tightening rotational direction. The loosening prevention nut 100 has a hole 30 extending in the axial direction with the same hole diameter continuously to the minimum hole diameter of the tapered portion 60. The taper portion 60 gradually crushes the screw thread 44 of the male screw portion 41 of the bolt 40 so as not to be screwed with the female screw portion 20 of the loosening prevention nut 100 when the loosening prevention nut 100 is tightened and rotated. Plastically deform. Finally, the hole 30 plastically deforms the thread 44 of the male screw 41 of the bolt 40 to the hole diameter of the hole 30.
For this reason, the force when the loosening prevention nut 200 is rotated by the user using the jig in the tightening and rotating direction may be smaller than in the case where the loosening prevention nut 100 of the first embodiment is rotated.

According to the second embodiment, the female screw 20 and the hole 30 are continuously formed via the tapered portion 60 whose diameter decreases from the female screw 20 toward the hole 30.
According to this configuration, when passing through the tapered portion 60, the thread 44 of the male screw portion 41 of the bolt 40 gradually performs plastic deformation to reduce the diameter. For this reason, the force when the loosening prevention nut 200 is tightened and rotated by the user using the jig may be small.

  20 female screw part, 21 end face, 22 thread, 23 inner diameter, 30 hole part, 31 end face, 40 bolt, 41 male screw part, 42 male screw outer diameter, 43 male thread valley diameter, 44 thread, 45 thread groove, 46 outer circumferential surface, 47 boundary, 50 to-be-fastened member, 51 mounting hole, 60 taper portion, 100 loose lock nut, 200 loose lock nut.

Claims (6)

A female screw portion which is continuous from the opening portion opened to one end face and which is screwed to the male screw portion of the mating member;
A hole which is continuous with an opening at the other end face and which has a diameter smaller than the external diameter of the external thread of the external thread of the mating member and which is larger than the diameter of the external thread valley;
Equipped with
A looseness which plastically deforms a screw thread of an external thread portion of the mating member when it is attached to the mating member from the female screw side and tightened and rotated with respect to the mating member to be screwed together Prevent nut.   The loosening prevention nut according to claim 1, wherein a center line of the female screw portion and the hole portion coincide with each other.   The loosening prevention nut according to claim 1 or 2, wherein the female screw portion and the hole portion are formed continuously.   The loosening prevention nut according to claim 1 or 2, wherein the female screw portion and the hole portion are continuously formed via a tapered portion whose diameter decreases from the female screw portion toward the hole portion. In the hole, the thread of the male thread of the mating member is plastically deformed to fill the thread groove of the male thread of the mating member, and the male thread of the mating member is larger than the inner diameter of the female thread. The loosening prevention nut according to any one of claims 1 to 4, which is a hole diameter configured to a diameter.   An external thread is formed continuously from an opening opened in one end face, and an external thread is continued from an opening opened in the other end face, and an external thread is formed on the other end of the external thread. A loosening prevention nut having a hole smaller than the diameter and larger than the diameter of the external thread valley is attached to the opposing member from the female screw side, and the screw is engaged The fastening method of plastically deforming the screw thread of the external thread part of the other member at the hole when tightening and rotating the member.

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