JP2007327535A - Screw anti-loosening structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw anti-loosening structure for eliminating the need for additional components including a split pin while actualizing highly reliable anti-loosening effects only with fastening work. <P>SOLUTION: The screw anti-loosening structure comprises a bolt 110 having a shaft portion 110B on which a male screw portion 111 is provided and on the outer peripheral face of which a recessed portion 112 is formed, a nut 120 having a female portion 121 to be threaded to the male screw portion 111 and a plastically deformable portion 122 to be plastically deformable, and a washer 130 having an introducing portion 132 for introducing the plastically deformable portion 122 of the nut 120 to the recessed portion 112 of the bolt 110 in accompany with the fastening of the bolt 110 to the nut 120. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a screw locking structure, and more particularly to a screw locking structure that can achieve locking only by a fastening operation.

  Conventionally, when two or more members are fastened, screw fastening with bolts and nuts is often used, but how to prevent this screw from loosening is a long-standing problem, and various screw locking prevention A structure has been proposed.

For example, (1) a method using a grooved nut and a split pin, (2) a method using a tongue washer, (3) a method using a lock wire, (4) a method using a double nut, (5 ) A method of using a screw lock agent is known, and (6) A method of inserting a rotation-preventing pin between a male screw portion and a female screw portion (for example, see Patent Document 1) is also newly proposed. Has been.
JP 2000-220624 A

  However, in the conventional screw locking structure as described above, it is necessary to perform a locking operation in addition to the fastening operation, and there is a problem that workability deteriorates. Furthermore, in (1), (3), (4), (5) and (6), there is a problem that the cost increases due to an increase in the number of parts. In (1) and (6), the pin is inserted into the hole. Therefore, there is a problem that a sufficient fastening force cannot be obtained depending on the positional relationship between the two.

  SUMMARY OF THE INVENTION In view of such circumstances, the present invention is intended to provide a screw locking structure that not only provides a reliable locking effect only by fastening work but also does not require an additional part such as a split pin. It is.

  The present invention relates to a screw locking structure and is achieved by the following means.

  (1) The present invention has a shaft portion provided with a male screw portion, a bolt having a recess formed on the outer peripheral surface of the shaft portion, a female screw portion screwed into the male screw portion, and plastic deformation is possible. A nut having a plastic deformation portion, and a washer having an introduction portion that guides the plastic deformation portion of the nut to the concave portion of the bolt when the bolt and the nut are fastened. This is a screw locking structure that is characterized.

  (2) In the present invention, the plastic deformation portion is a cylindrical body that protrudes from the seat surface of the nut and has a shape whose outer diameter decreases toward the tip, and the concave portion is a circle of the shaft portion. It is a belt-like groove formed over the entire circumference in the circumferential direction, and the introduction portion is a tapered hole formed at a position facing the cylindrical body and having an inner diameter expanding toward the cylindrical body. The screw locking structure according to (1) above.

  (3) The present invention is also characterized in that the cylindrical body projecting from the seating surface of the nut is divided into a plurality of parts in the circumferential direction, and the loosening prevention of the screw according to (2) above Structure.

  According to the screw locking structure according to claims 1 to 3 of the present invention, it is possible to obtain a reliable locking effect only by fastening work, and an additional part such as a split pin is not required. Can have an effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, the structure of the screw locking structure 100 according to the embodiment of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view showing a configuration of a screw locking structure 100 according to this embodiment. FIGS. 2A and 2B are a schematic front view and a schematic view of a nut 120 according to this embodiment. It is a bottom view.

  As shown in FIG. 1, the screw locking structure 100 according to the present invention includes a bolt 110, a nut 120, a tapered washer (washer according to the present invention) 130, and a plain washer 140. Fastened materials 150 and 151 are fastened.

  In the drawing, the bolt 110 and the nut 120 are in a state before being fastened.

  The bolt 110 includes a hexagonal columnar head portion 110A and a columnar shaft portion 110B. The shaft portion 110B has a threaded portion 111 on the outer peripheral surface and a belt-like groove portion 112. This groove portion 112 is located in the vicinity of a position separated from the proximal end of the shaft portion 110B by the thicknesses h1 and h2 of the fastened materials 150 and 151 and the thickness h3 of the tapered washer 130 in the vicinity of the shaft portion 110B. In the direction, it is formed over the entire circumference with a substantially arc-shaped cross-sectional shape.

  As shown in FIGS. 2 (a) and 2 (b), the nut 120 has a hexagonal columnar shape, and is screwed into the internal threaded surface 111 of the bolt 110 with the inner peripheral surface of the hole 120B formed in the center. A threaded portion 121 is provided, and a plastically deformable cylindrical body 122 projects integrally from the seating surface 120 </ b> A toward the tapered washer 130. The cylindrical body 122 has a first tapered portion 122A and a second tapered portion 122B whose outer diameter decreases toward the tip, and is divided into a plurality of portions in the circumferential direction by slits 122C.

  Returning to FIG. 1, the tapered washer 130 has a disk shape, and is formed in the center, and is coaxial with the hole 131 on the side facing the nut 120 and the hole 131 through which the shaft part 110 </ b> B of the bolt 110 passes. And has a tapered hole 132 whose inner diameter increases toward the nut 120.

  In the present embodiment, the tapered hole 132 and the first tapered portion 122A of the cylindrical body 122 have the same slope so that they can slide smoothly after contacting each other. However, the gradient or shape may be different depending on the material, the lubrication condition of the contact portion, and the like.

  Next, the operation of the screw locking structure 100 according to this embodiment will be described.

  3A and 3B are schematic cross-sectional views showing the operation of the screw locking structure 100. FIG.

  As shown in FIG. 5A, when the nut 120 is tightened to the bolt 110 in the fastening operation, first, the first tapered portion 122A of the cylindrical body 122 contacts the tapered hole 132 of the tapered washer 130.

  As the nut 120 is further tightened, the first taper portion 122A slides along the inclined surface of the taper hole 132, and the entire cylindrical body 122 is plastically deformed so as to project radially inward. When the tapered portion 122B comes into contact with the tapered hole 132, the tip of the cylindrical body 122 comes into contact with the bottom of the groove portion 112 of the bolt 110 and is crushed. For this reason, the cylindrical body 122 is plastically deformed so as to fill the groove 112 of the bolt 110 as the nut 120 is tightened.

  When the fastening is completed, as shown in FIG. 5B, the entire cylindrical body 122 is completely filled in the groove portion 112 and the tapered hole 132 of the bolt 110 by plastic deformation, and thereby the plastically deformed cylindrical body. 122 is securely locked to the groove 112 of the bolt 110.

  As described above, since the cylindrical body 122 of the nut 120 that is plastically deformed is locked to the groove 112 of the bolt 110, the axial movement of the nut 120 is limited. Rotation along 111 can be prevented. That is, it is possible to prevent the bolt 110 and the nut 120 from being loosened.

  In this embodiment, since the cylindrical body 122 is divided into eight in the circumferential direction by the slits 122C, it is possible to easily plastically deform the cylindrical body 122 inward with a small force. For this reason, an excessive force is not required for the fastening force.

  Note that the number of divisions of the cylindrical body 122 is not limited to eight, and an optimum number of divisions may be employed depending on the material, size, shape, and the like, and may not be divided at all depending on conditions.

  As described above, according to the screw locking structure 100 according to the present embodiment, the shaft portion 110B provided with the male thread portion 111 is provided, and the concave portion (groove portion in the present embodiment) is formed on the outer peripheral surface of the shaft portion 110B. ) 112, a nut 120 having a female thread portion 121 screwed with the male thread portion 111, and a plastic deformation portion (cylindrical body in this embodiment) 122 capable of plastic deformation, a bolt 110 and a nut 120. And a washer (tapered washer in this embodiment) 130 having an introduction portion (tapered hole in this embodiment) 132 that guides the plastic deformation portion 122 of the nut 120 to the recess 112 of the bolt 110 in accordance with the fastening. By being configured, a highly reliable loosening prevention effect can be obtained only by a fastening operation, and an excellent effect of not requiring an additional part such as a split pin can be obtained.

  The plastic deformation portion 122 is a cylindrical body 122 that protrudes from the seating surface 120A of the nut 120 and has a shape whose outer diameter decreases toward the tip, and the recess 112 includes all of the shaft portion 110B in the circumferential direction. It is a belt-like groove portion 112 formed over the circumference, and the introduction portion 132 is a tapered hole 132 that is formed at a position facing the cylindrical body 122 and whose inner diameter increases toward the cylindrical body 122. Since the cylindrical body 122 that has been plastically deformed is reliably locked to the groove portion 112 by being smoothly guided to the groove portion 112 and filled with the groove portion 112 by 132, it is more efficient and reliable while performing only the fastening operation. High anti-loosening effect can be obtained.

  Further, since the cylindrical body 122 protruding from the seat surface 120A of the nut 120 is divided into a plurality of parts in the circumferential direction, the cylindrical body 122 can be plastically deformed with a small force. Since the required force can be prevented from becoming excessive, a highly reliable anti-loosening effect can be obtained without deteriorating workability.

  It should be noted that the screw locking structure according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, the groove portion 112, the cylindrical body 122, and the tapered hole 132 are not limited to the shapes shown in the present embodiment, but depending on the size and material of the bolt 110 and the nut 120, the magnitude of the force acting on them, and the like. Various shapes can be employed.

  In this embodiment, the cylindrical body 122 is formed integrally with the nut 120. However, the present invention is not limited to this. For example, the cylindrical body 122 that is easily plastically deformed is difficult to be plastically deformed. It is good also as a structure joined to the nut 120 of material by welding etc.

  In this embodiment, the bolt 110 has the male threaded portion 111 in the entire length of the shaft portion 110B. However, the present invention is not limited to this, and for example, the nut 120 on the tip side of the groove portion 112 is used. It is good also as a structure which has the thread part 111 only in the part screwed with the female thread part 121. FIG.

  The screw locking structure of the present invention can be particularly used in the field of screw fastening widely used in industry.

It is a schematic sectional drawing which shows the structure of the locking structure of the screw which concerns on the Example of this invention. It is the schematic front view (a) and schematic bottom view (b) of the nut which concern on the Example of this invention. It is a schematic sectional drawing (a) and (b) which shows the effect | action of the screw locking structure which concerns on the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Screw loosening prevention structure 110 ... Bolt 110B ... Shaft part 111 ... Male thread part 112 ... Groove part 120 ... Nut 120A ... Seat surface 121 ... Female thread part 122 ... Cylinder 130 ... Tapered washer 132 ... Tapered hole

Claims (3)

A bolt having a shaft portion provided with a male screw portion and having a recess formed on the outer peripheral surface of the shaft portion;
A nut having a female thread part that is screwed with the male thread part and a plastic deformation part capable of plastic deformation;
A screw locking structure comprising: a washer having an introduction portion that guides the plastic deformation portion of the nut to the recess of the bolt when the bolt and the nut are fastened. . The plastic deformation portion is a cylindrical body that protrudes from the seat surface of the nut and has a shape whose outer diameter decreases toward the tip.
The recess is a strip-shaped groove formed over the entire circumference of the shaft portion in the circumferential direction,
The introduction part is a tapered hole formed at a position facing the cylindrical body and having an inner diameter expanding toward the cylindrical body.
The screw locking structure according to claim 1. The cylindrical body projecting from the seat surface of the nut is divided into a plurality in the circumferential direction,
The screw locking structure according to claim 2.

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