JP6231807B2 - Bolt locking structure - Google Patents

Description

  The present invention relates to a bolt loosening prevention structure, and more particularly, to a structure that can securely loosen a bolt without incurring manufacturing complexity.

  The method of fastening using bolts is adopted in many structures. The bolt is simply screwed and tightened to the female screw formed on the member to be fastened, or simply screwed into the nut on the back side through the member to be fastened and tightened. There is a concern that loosening of the fastening may occur due to initial looseness due to roughness, waviness or shape error of the contact portion, return rotation of the nut due to static fluctuation or dynamic fluctuation of the axial force, and the like.

  In contrast, a plurality of elastic claws are provided on the outer surface of the bolt head or the inner surface of the hole into which the bolt head to be fastened is fitted, and the plurality of claws swing in the bolt tightening direction. In the loosening direction, a bolt loosening prevention structure that is pressed against the inner surface of the hole to be fastened or the outer side surface of the bolt head in the loosening direction to prevent rotation in the loosening direction is provided. It has been proposed (Patent Document 1).

JP 2007-255429 A

  However, since the claw body is pressed against the inner surface of the hole or the outer surface of the bolt head in the loosening prevention structure described in Patent Document 1, a plurality of claw bodies are provided to securely prevent the bolt from loosening. It was necessary and the production was complicated.

  In view of such problems, an object of the present invention is to provide a bolt loosening prevention structure capable of securing the loosening prevention performance without incurring manufacturing complexity.

  Therefore, in the bolt loosening prevention structure according to the present invention, an inner cylindrical cap is press-fitted into the hole of the fastening member into which the bolt is inserted, and an operation tool is placed on the top surface of the outer cylindrical shape of the bolt. A polygonal recessed portion that can be fitted is formed, and the bolt head is rotatably fitted to the cap while the recessed portion is fitted on the outer surface of the bolt head or the inner surface of the hole of the fastened member. The bottom of the fitting recess is formed in a shape that gradually becomes shallower toward the advancing side in the bolt tightening direction with respect to the outer side surface of the bolt head or the inner side surface of the hole of the fastening member, A rollable stopper whose outer shape is spherical or cylindrical is housed in the fitting recess, and the stopper is biased toward the bolt tightening direction advance side on the bolt tightening direction delay side of the stopper. Spring member is provided When the bolt rotates in the tightening direction, the stopper rolls against the biasing force of the spring member to the delayed side of the bolt tightening direction, thereby allowing the bolt head to rotate in the tightening direction. When the bolt rotates in the slack direction, the stopper is rolled to the slack direction in the slack direction of the bolt by the biasing force of the spring member, and the bottom face of the bolt head or the fitting recess of the cap and the inner peripheral face of the cap or the bolt head. It is characterized in that rotation in the slack direction of the bolt head is prevented by being pinched between the outer peripheral surface of the part.

  One of the features of the present invention is that a fitting recess is formed on the outer side surface of the outer cylindrical head of the bolt or the inner side surface of the inner cylindrical cap, and the bottom surface of the fitting recess is advanced in the bolt tightening direction. In this point, it is formed in a shape that gradually becomes shallower toward the end, and a stopper having a rollable shape is housed in the fitting recess and is urged toward the advancing side in the bolt tightening direction by a spring member. .

  As a result, when the bolt is rotated in the tightening direction, the stopper is slidably contacted with the inner surface of the cap or the outer surface of the bolt head, thereby rotating the bolt toward the bolt tightening direction delay side against the biasing force of the spring member. Since it is moved and located in the deep part of the bottom of the insertion recess, the stopper can be smoothly rotated without obstructing the rotation of the bolt head in the tightening direction.

  On the other hand, when the tightening of the bolt is completed, the stopper is rolled toward the slack direction of the bolt by the biasing force of the spring member. If the bolt tries to rotate in the slack direction in this state, the bolt head or the cap insertion recess bottom surface and the cap inner peripheral surface or the bolt head outer peripheral surface will be strongly sandwiched, The stopper prevents the rotation in the slack direction.

  In addition, since the rollable stopper is firmly sandwiched between the bottom surface of the insertion recess and the inner peripheral surface of the cap or the outer peripheral surface of the bolt head, it prevents rotation of the bolt head in the slack direction. As in the structure described in Document 1, the force to prevent rotation is large compared to the method in which the claw body is stretched to prevent rotation, and it is possible to reliably prevent loosening with a small number of, for example, one stopper.

  Furthermore, since it is only necessary to set a stopper and a spring member in the fitting recess, the bolt can be prevented from loosening with a simple structure, and the manufacturing is not complicated.

  The insertion recess may have a shape such that the bottom surface gradually becomes shallower toward the advancing side of the bolt tightening direction, and the bolt head or the top surface side of the cap may remain closed or may be opened. In particular, when opened, the stopper can be fitted into the recess from the top surface side, and the assembly work can be performed smoothly.

  The stopper is not particularly limited as long as it has an outer spherical shape or an outer cylindrical shape and can roll in the insertion recess.

  The cap has only to be cylindrical with an inner diameter, and the outer shape is not particularly limited. If a cap having an arbitrary thickness is prepared, it is possible to deal with holes of various sizes in the fastened member with only one bolt.

It is a section lineblock diagram showing a desirable embodiment of a bolt loosening prevention structure concerning the present invention. It is a top view which shows the said embodiment. It is a figure for demonstrating the effect | action in the said embodiment. It is a top view which shows 2nd Embodiment. It is a figure for demonstrating the effect | action in the said embodiment.

  Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. 1 to 3 show a preferred embodiment of the bolt locking structure according to the present invention. In the figure, the loosening prevention structure of this example is composed of a combination of a bolt 10 and a cap 20. The bolt 10 has a male screw formed on the shaft portion, while the head portion 10A of the bolt 10 has an outer cylindrical shape, and a hexagonal recess 10B is formed on the top surface of the bolt head 10A. A hexagon wrench (operating tool) can be fitted and rotated.

  A plurality of, for example, four insertion recesses 10-C are formed on the outer surface of the bolt head portion 10A at equal angular intervals. The insertion recess 10C is formed in such a shape that the bottom surface 10C-1 gradually becomes shallower toward the advancing side of the bolt tightening direction with respect to the outer surface of the bolt head 10A, and the top surface side of the bolt head 10A is It is open.

  Further, a stopper 11 made of a metal ball is slidably accommodated in the insertion recess 10C, and a rectangular plate spring 12 is disposed on the side of the stopper 11 that is delayed in the bolt tightening direction, and the bottom surface 10C. The stopper 11 is urged toward the advancing side in the bolt tightening direction.

  On the other hand, the cap 20 has a cylindrical shape with a predetermined inner and outer diameter, is press-fitted into a hole 31 into which the bolt head 10A of the fastened member 30 is inserted, and the bolt head 10A is rotatably fitted in the cap 20. Yes.

  Now, when the bolt 10 is screwed into the fastened member 30, after the cap 20 is press-fitted into the hole 31 of the fastened member 30, the shaft portion of the bolt 10 is inserted into the hole 31 of the fastened member 30 and screwed into the female screw. When the bolt 10 is rotated in the tightening direction, the stopper 11 rolls against the urging force of the leaf spring 12 by slidingly contacting the inner surface of the cap 20 as shown in FIG. It is located in the vicinity of the deepest position of the insertion recess 10C, is held in the vicinity of the deepest position of the insertion recess 10C while being in sliding contact with the inner surface of the cap 20 and rotating in the insertion recess 10C. The bolt head 10A is smoothly rotated in the tightening direction without disturbing the rotation of the bolt head 10A.

  On the other hand, when the tightening of the bolt 10 is completed, the stopper 11 is positioned in the vicinity of the shallowest position of the fitting recess 10C by the urging force of the leaf spring 12 as shown in FIG. In such a situation, when the bolt 10 tries to rotate in the slack direction, the bolt 10A is strongly sandwiched between the bottom surface 10C-1 of the fitting recess 10C and the inner side surface of the cap 20, and the bolt head 10A rotates in the slack direction. Therefore, the bolt 10 can be surely prevented from loosening.

  4 and 5 show a second embodiment. In this example, a fitting recess 20 </ b> C is formed on the inner side surface of the cap 20, and the fitting recess 20 is such that the bottom surface 20 </ b> C- 1 gradually becomes shallower toward the advancing side in the bolt tightening direction with respect to the inner side surface of the cap 20. While being formed in a shape, the top surface side of the cap 20 is opened.

  Further, a stopper 11 made of a metal ball is slidably accommodated in the fitting recess 20C, and a rectangular plate spring 12 is disposed on the side of the stopper 11 that is delayed in the bolt tightening direction, and the bottom surface 20C. The stopper 11 is urged toward the advancing side in the bolt tightening direction.

  Now, when the bolt 10 is screwed into the fastened member 30, when the bolt 10 is rotated in the tightening direction, the stopper 11 is brought into sliding contact with the outer surface of the bolt head 10A as shown in FIG. Rolled against the urging force of the leaf spring 12, is positioned in the vicinity of the deepest position of the insertion recess 20C, and is slidably brought into contact with the outer surface of the bolt head 10A while being rotated in the insertion recess 20C. The bolt head 10A is smoothly rotated in the tightening direction without being held near the deepest position of the recess 20C and the stopper 11 obstructing the rotation of the bolt head 10A.

  When the tightening of the bolt 10 is completed, the stopper 11 is positioned in the vicinity of the shallowest position of the fitting recess 20C by the urging force of the leaf spring 12, as shown in FIG. In this situation, when the bolt 10 tries to rotate in the slack direction, the bolt head 10A is strongly sandwiched between the bottom surface 20C-1 of the insertion recess 20C and the outer surface of the bolt head 10A, and the bolt head 10A rotates in the slack direction. This prevents the bolt 10 from loosening.

10 bolt 10A head 10B recess 10C insertion recess 10C-1 bottom surface 11 stopper 12 leaf spring 20 cap 20C insertion recess 20C-1 bottom surface 30 fastened member 31 hole

Claims (2)

The fastened member (30) has an inner cylindrical cap (20) having a press-fit structure in a hole (31) of the fastened member (30) into which the bolt (10) is inserted , and the bolt (10) is an outer circle. The columnar head (10A) has a polygonal recess (10B) into which the operation tool can be fitted on the top surface , and the bolt head (10A) and the cap (20) have a rotatable loose fitting structure. on the other hand,
The bolt head (10A) or the fastened member (30) is fitted into the outer surface of the bolt head (10A) or the inner surface of the hole (31) of the fastened member (30) (10C, 20C) , and the insertion recesses (10C, 20C) are surfaces that stand in the radial direction with respect to the outer peripheral surface of the bolt head (10A) or the inner surface of the hole (31) of the fastened member (30). Continuing on the edge of the standing surface, the outer surface of the bolt head (10A) or the inner surface of the hole (31) of the fastened member (30) gradually becomes shallower toward the advancing direction of the bolt tightening direction. The bottom surface (10C-1, 20C-1) has a shape, and the top surface side of the fitting recess (10C, 20C) is opened , and the outer shape is spherical in the fitting recess (10C, 20C). Or a cylindrical stopper (11) that can be rolled is stored. The fitting narrowing recess (10C, 20C) rising surface and the bottom surface is in the (10C-1,20C-1) plane ∠ is pressed against the shape of the leaf spring (12) is interposed, the leaf spring ( 12) urges the stopper (11) toward the advancing side of the bolt tightening direction ,
When the bolt rotates in the tightening direction, the stopper (11) rolls in the bolt tightening direction delay side against the biasing force of the leaf spring (12), thereby rotating the bolt head (10A) in the tightening direction. While accepting
When the bolt rotates in the slack direction, the stopper (11) is rolled to the slack direction of the bolt by the urging force of the leaf spring (12), and the bolt head (10A) or the cap (20) is fitted. The bolt head is clamped between the bottom surface (10C-1, 20C-1) of the recessed recess (10C, 20C) and the inner peripheral surface of the cap (20) or the outer peripheral surface of the bolt head (10A). A bolt loosening prevention structure characterized in that rotation in the loosening direction is prevented.   The bolt loosening prevention structure according to claim 1, wherein the stopper (11) is constituted by a metal ball, a metal round bar, or a metal round pipe.

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