JP6757101B2 - Loosening prevention fastening structure - Google Patents

Description

The present invention relates to a fastening structure for tightening and fixing an object to be fastened with a fastener made of a nut and a bolt, and more particularly to a locking structure having a suitable locking action.

Nuts and bolts are widely used in various fields as fastening members used for tightening and fixing parts and members. These nuts and bolts are for tightening and fixing parts and members, but there is a problem that the nuts and bolts loosen when vibrations repeatedly act on these fastening parts, so the nuts and bolts should be prevented from loosening. A wide variety of means and methods have been proposed for the purpose, some of which have been put to practical use.

For example, Patent No. 4495849 discloses locking nut disclosed in (Patent Document 1) is an application of the locking action of the double nut, consists of a lower nut and the upper nut threaded hole is formed, The lower nut is formed with an eccentric convex portion having a tapered outer peripheral surface, the upper nut is formed with a concave portion into which the convex portion of the lower nut is fitted, and the convex portion and the concave portion are eccentric to both. Each nut is radially displaced with respect to the center of the screw hole, and radial stress is applied to the screw shaft to prevent loosening.

In addition to the double nut type, various structures have been proposed in which a washer is used to prevent loosening. For example, Japanese Patent Application Laid-Open No. 2015-17657 (Patent Document 2), Japanese Patent Application Laid-Open No. 2011-220387 (Patent Document 3), Japanese Patent Application Laid-Open No. 2016-223625 (Patent Document 4), and Utility Model Registration No. 3131351 (Patent Document 3). The locking nut disclosed in Document 5) is formed by arranging a plurality of inclined surfaces that allow the rotation direction of the bolt and rotation blocking portions that prevent the rotation of the bolt in the circumferential direction on the seat surface of the nut and the surface of the washer. , It is designed to prevent rotation by fitting it into each rotation blocking part.

Further, as another method of preventing loosening by using a washer, the locking nut disclosed in Japanese Patent Application Laid-Open No. 10-153211 (Patent Document 6) has a ring-shaped washer having a gently inclined surface on one surface. When the nut is screwed and tightened, the nut is tilted by the inclined surface to increase the surface pressure on the bolt and prevent it from loosening.

Japanese Patent No. 44955849 Japanese Unexamined Patent Publication No. 2015-17657 Japanese Unexamined Patent Publication No. 2011-220387 JP-A-2016-223625 Utility Model Registration No. 3131351 Japanese Unexamined Patent Publication No. 10-153211

The loosening prevention nut illustrated in Patent Document 1 uses a so-called double nut to prevent loosening. However, the two nuts and the bolts have the same screw direction, and when vibration is repeated, the two nuts are used. Can rotate and the problem of loosening remains unsolved. In addition, since two nuts are used and the structure of each nut is complicated, there is a problem that the cost rises, and it is used only for some special purposes, and there is also a problem that it is not versatile. is there.

Further, in the loosening prevention structure using the washer illustrated in Patent Documents 2 to 5, an inclined surface and a rotation blocking portion are formed on the seat surface of the nut and the surface of the washer, and the rotation blocking portion is used to prevent rotation. However, when the nut is rotated to get over the inclined surface and fit into the rotation blocking portion, the nut moves in the loosening direction in the axial direction, so that the locking action of the nut is reduced and the frictional force of the washer is also reduced. Therefore, when the vibration is repeated, the nut and the washer whose tightening force is reduced rotate together, so that there is a problem that the loosening prevention effect is lost.

Further, the anti-loosening structure using the washer illustrated in Patent Document 6 is formed on one surface of the ring-shaped washer on a gently inclined surface so that the nut is inclined by this inclined surface to increase the surface pressure on the bolt. I have to. However, tilting the nut forcibly bends the bolt, which increases stress on the bolt, which causes a problem of shortening the life. Further, if the entire surface of one surface of the nut is not joined to the inclined surface of the washer, the nut only abuts on a part of the washer and the frictional force is significantly reduced, so that the loosening prevention effect is also lost. It becomes.

The problem to be solved by the present invention is that even if the bolt member or the nut member tries to rotate in the loosening direction due to vibration, the loosening prevention action can be increased by the synergistic action with the washer, even if the configuration is simple and inexpensive. The purpose is to provide a locking structure.

Therefore, the anti-loosening fastening structure according to the present invention is a fastening structure in which a fastener composed of a bolt member and a nut member is screwed to fasten the fastened body, and the head of the fastener and the fastened body are joined to each other. A washer is interposed between the washer, and the washer surface to be surface- joined to the object to be fastened is formed in a plane perpendicular to the axis, and the opposite washer joint surface is formed in an inclined plane and a top is formed. A through hole is formed in the center through which the bolt member is inserted, and a head formed on a washer joint surface opposite to the washer seat surface and the head itself of the fastener to be joined to the washer joint surface. The joint surface is formed on a plane inclined at the same angle as the washer joint surface, and the bottom is formed on the head joint surface, and the inclination angle of these planes is set to the lead of the male screw portion of the to be fastened and the female screw portion of the nut member. The gist is that the friction area of the seat surface, which is formed to be 1 times the angle and surface-joined to the object to be fastened, is larger than the friction area due to the screwing of the male and female threads of the washer.

Further, it is desirable to form one locking portion for locking with respect to the tightening direction of the fastener on the head joint surface of the fastener and the washer joint surface of the washer. Further, engaging portions with which the rotary fasteners are engaged are formed on the head of the fastener and the peripheral edge of the seat, and the engaging portions are the dimensions of the planes of the side surfaces formed on the left and right. Is formed in a substantially C shape with one side small and the other side greatly different, and the rotary fastener is formed in a substantially C shape that engages with the left and right side surfaces of the engaging portion and has an engaging surface. However, it is desirable to allow the rotary fastener to be inserted from the one side and prevent the rotary fastener from being inserted from the other side.

According to the present invention, a washer joint surface of a washer interposed between a head joint surface of the head of a fastener made of a bolt member or a nut member and a body to be fastened so as to be joined to the head joint surface. Is formed on an inclined flat surface, and the seating surface of the washer to be joined to the object to be fastened is formed on a flat surface perpendicular to the axis line, so that the fastener of the bolt member or nut member to which vibration is applied tries to rotate. Since the head joint surface and the washer joint surface are inclined, the washer seat surface presses against the object to be fastened to increase the frictional force, while the male and female threads press the fastener. As a result, the frictional force increases, so that the rotational displacement of the fastener is prevented. Further, when the nut member or the bolt member is rotated and displaced due to vibration, only the top of the washer comes into contact with the inclined head joint surface of the nut member, and a gap is created in other parts. Since the joint area between the part joint surface and the washer joint surface of the washer becomes smaller, the frictional force between the two decreases, the nut member rotates smoothly due to vibration, and the nut member separates from the washer, resulting in looseness. The stopping action is promoted. Moreover, since the inclination angle of these planes is formed to be 1 times that of the male threaded portion of the object to be fastened and the female threaded portion of the nut member, the rotational displacement of the nut member or the like due to vibration becomes easy, and the loosening prevention action is expanded. It becomes possible to. Further, since the friction area of the seat surface to be surface-bonded to the washer to be fastened is formed to be larger than the friction area due to the screwing of the male and female threads of the fastener, the washer is formed by a large frictional force between the washer and the to be fastened. Since the immovable state is maintained and only the nut member or the like rotates, the loosening prevention action can be reliably exerted.

Further, by forming one locking portion that locks with respect to the tightening direction of the fastener on the head joint surface of the fastener and the washer joint surface of the washer, when the fastener is rotated and tightened, the head is tightened. Since the locking portion of the joint surface is engaged with the locking portion of the washer joint surface and comes into contact with each other, the positions of the fastener and the washer in the rotational direction are automatically determined. Therefore, the head joint surface and the washer joint surface The entire surface of the can be surface-joined. As a result, even if the fastener is slightly rotated due to vibration or the like, the fastener and the washer are separated from each other due to the inclination of the head joint surface and the washer joint surface, so that the fastener is rotationally displaced due to an increase in frictional force. Can be stopped in a short time. Further, for example, in addition to the hexagon socket head bolt, even if the hexagon socket head cap screw is used, the rotational displacement of the hexagon socket head bolt is similarly shortened by forming one locking portion on the head joint surface and the washer joint surface. Can be blocked in time.

Furthermore, on the head of the fastener and the peripheral edge of the seat, an engaging portion with which the rotary fastener is engaged is formed, and each engaging portion has dimensions of the flat surfaces of the side surfaces formed on the left and right. The rotary fastener is formed in a substantially C shape that engages with the left and right side surfaces of the engaging portion, while the one side is formed in a substantially C shape with the other side greatly different. As a result, the rotary fastener is allowed to be inserted from one side only when the head joint surface of the fastener and the seat joint surface of the seat are surface-joined, so that both can be tightened from the correct surface-joined state. .. Further, even if the rotation direction of the fastener and the washer is slightly displaced, when the rotary fastener is inserted from one side of the fastener and the washer, the engaging portion of the rotary fastener is the engagement portion of the fastener and the washer. Since one of them automatically rotates and matches along the left and right side surfaces, it is possible to offset the entire surface of the head joint surface and the washer joint surface at the correct position.

It is sectional drawing which shows the fastening state of the loosening prevention fastening structure which concerns on this invention. It is explanatory drawing which shows the inclination angle of the nut member in the loosening prevention fastening structure. It is explanatory drawing which shows the inclination angle of the washer in the loosening prevention fastening structure. (A) and (B) are plan views showing indexes of a nut member and a washer. It is a side view which shows the index of a nut member and a washer in another embodiment. (A) and (B) are explanatory views showing a loosening prevention action. (A) and (B) are explanatory views which show the friction surface of a nut member and a washer. It is sectional drawing which shows the 2nd Example of the loosening prevention fastening structure which concerns on this invention. It is explanatory drawing which shows the inclination angle of the bolt member in the locking structure. It is a side view which shows the 3rd Example of the loosening prevention fastening structure which concerns on this invention. It is an exploded perspective view of the loosening prevention fastening structure shown in FIG. (A) and (B) are explanatory views showing the tightening and loosening prevention action in the third embodiment. It is a top view which shows the fastener as the 4th Example of the loosening prevention fastening structure which concerns on this invention. It is a top view which shows the washer as the 4th Example of the loosening prevention fastening structure which concerns on this invention. (A) and (B) are explanatory views which show the tightening work start state in 4th Example. It is a top view which shows the other Example of the rotary fastener used in 4th Example. It is a side view which shows the 5th Example of the loosening prevention fastening structure which concerns on this invention.

The locking structure for preventing loosening of the present invention is a fastening structure for fastening a fastened body by screwing a fastener composed of a bolt member and a nut member, and is between the head of the fastener and the fastened body. The seat surface to which the washer is surface- joined to the object to be fastened with the washer interposed therebetween is formed in a plane perpendicular to the axis, and the opposite washer joint surface is formed in an inclined plane and a top is formed. A through hole is formed in the center through which the bolt member is inserted, and a washer joint surface opposite to the washer seat surface and a head joint surface formed on the head itself of the fastener to be joined to the washer joint surface. Is formed on a plane inclined at the same angle as the washer joint surface, and a bottom portion is formed on the head joint surface, and the inclination angle of these planes is set to the lead angle of the male screw portion of the fastened body and the female screw portion of the nut member . The friction area of the seat surface that is formed once and surface-joined to the object to be fastened of the washer is formed to be larger than the friction area due to the screwing of the male and female threads of the fastener.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of an anti-loosening fastening structure according to the present invention, and shows a state in which the object to be fastened is fastened by a nut member. For example, a through hole 1a is formed in a substrate 1 made of a metal plate, and a screw portion 2a of a bolt member 2 is inserted through the through hole 1a. The object to be fastened 3 in which the through hole 3a is formed is superposed on the substrate 1, and the threaded portion 2a of the bolt member 2 is inserted into the through hole 3a. The tip end side of the threaded portion 2a of the bolt member 2 protrudes from the fastened body 3. The bolt member 2 is a general commercial product, and the seat surface 2b of the head is joined to the substrate 1 and is immobile due to frictional action in the tightened state.

A nut member 5 is screwed onto the tip end side of the bolt member 2 protruding from the body to be fastened 3 with a washer 4 interposed therebetween. Like a commercially available nut, the nut member 5 has a head portion 5a formed in the shape of a hexagon nut as shown in FIG. 4, and as shown in FIG. 2, a head joint surface to be joined to the washer 4 of the head portion 5a. 5b is formed on an inclined flat surface. A female screw is formed on the inner peripheral surface. The inclination angle θ1 of the head joint surface 5b is set to be one times the lead angle θ2 of the female screw of the nut member 5 and the male screw of the bolt member 2. Further, a bottom portion 5c is formed on the head joint surface 5b by inclining a flat surface.

On the other hand, as shown in FIGS. 3 and 4, the washer 4 has a through hole 4a formed in the center through which the bolt member 5 is inserted, and the outer shape is formed into a hexagon having the same size as the nut member 5. Further, the seat surface 4b to be joined to the fastened body 3 is formed on a plane perpendicular to the axis C of the bolt member 2 and the nut member 5, and the washer joint surface 4c opposite to the seat surface 4b is the nut member 5. The head joint surface 5b is formed at the same angle as the inclination angle θ1, and is set to 1.0 to 3.0 times the lead angle θ2 of the female screw of the nut member 5 and the male screw of the bolt member 2. As a result, when the head joint surface 5b of the nut member 5 is joined to the washer joint surface 4c of the washer 4, the joint portion becomes one line as shown in FIG. Further, a top portion 4d is formed at the thickest portion of the washer joint surface 4c.

As described above, the inclination angle θ1 of the washer joint surface 4c of the washer 4 and the head joint surface 5b of the nut member 5 is set to 1.0 to 3.0 times the lead angle θ2, as will be described later. The nut member 5 rotates in the loosening direction when vibration is applied, in order to exert a loosening prevention effect at this time. That is, when the inclination angle θ1 is set to less than 1.0 times the lead angle θ2, the rotation distance of the nut member 5 until the anti-loosening effect occurs becomes large, and when the nut member 5 loosens slightly, The anti-loosening effect cannot be obtained. Further, when the inclination angle θ1 is set to 3.0 times or more the lead angle θ2, the nut member 5 becomes difficult to rotate due to the steep angle, and the loosening prevention effect cannot be obtained. Therefore, the above angle is set as a range in which the nut member 5 can rotate smoothly and the anti-loosening effect can be obtained in a short time. The inclination angle θ1 is preferably 1. Of the lead angle θ2. It is 1 to 2.2 times.

Further, the reason why the heads of the washer 4 and the nut member 5 are formed in a hexagonal shape is to engage a rotary fastener such as a spanner or a wrench (not shown), and the peripheral portion of the washer 4 and the nut member 5 is formed. The rotary fasteners are engaged with each side of the wrench as an engaging portion. The heads of the washer 4 and the nut member 5 may be hexagonal, quadrangular, or substantially elliptical with engaging portions of surfaces parallel to both sides.

Further, when the washer 4 and the nut member 5 are joined, the thickest top 4d of the washer joint surface 4c of the washer 4 and the thinnest bottom 5c of the head joint surface 5b of the nut member 5 are combined, and the washer joint surface 4c and the head are combined. It is necessary that the partial joint surfaces 5b are surface-bonded. For this reason, FIGS. 4 and 5 are provided with indexes for positioning and surface-joining the two. The positioning indexes 4e and 5d shown in FIG. 4 are examples in which the portion where the two sides of the hexagonal head of the washer 4 and the nut member 5 intersect is cut out flat and used as an index. It is desirable that the positions of the indexes 4e and 5e are formed so that the top 4d of the washer joint surface 4c and the bottom 5c of the head joint surface 5b coincide with each other. Further, the positioning indexes 4f and 5e shown in FIG. 5 are used as indexes by applying paint, and the positions of the indexes 4f and 5e are positioned at the top 4d of the washer joint surface 4c as in the example shown in FIG. , And it is desirable to form the bottom 5c of the head joint surface 5b so as to coincide with each other.

Next, the anti-loosening action of the anti-loosening fastening structure of the present invention will be described with reference to FIG. FIG. 6A shows a state in which the object to be fastened 3 is fastened by the nut member 5 and then vibrated. When the vibration is applied in this way, the nut member 5 first rotates as shown by an arrow. That is, the seat surface 4b of the washer 4 is surface-bonded to the object to be fastened 3 and has a wide friction area F1 as shown in FIG. 7B. On the other hand, the nut member 5 has a narrow friction area F2 as shown in FIG. 7A because the male screw of the bolt member 2 and the female screw of the nut member 5 are screwed together and the threaded portion is joined. .. Moreover, in the normal screwed state, not all the threads of the nut member 5 and the bolt member 2 are joined, and it is generally said that 3 to 5 threads are joined. Therefore, the friction area F2 in the nut member 5 is about one-fifth of the friction area F1 in the seat surface 4b of the washer 4. Therefore, when vibration is applied, the nut member 5 starts to rotate in the loosening direction indicated by the arrow, and the washer 4 is maintained in an immobile state due to a large frictional force with the object to be fastened 3.

After that, the nut member 5 rotates due to the application of vibration, and the state shown in FIG. 6B is obtained. FIG. 6B is a view of FIG. 6A viewed from the left side of the drawing, in which the top portion 4d of the washer 4 and the bottom portion 5c of the nut member 5 are in front of the drawing. As the nut member 5 rotates, the bottom portion 5c of the nut member 5 tends to move to the right in the drawing with respect to the top portion 4d of the washer 4. At this time, since the side of the bottom portion 5c of the nut member 5 is an inclined surface that becomes higher, the nut member 5 is separated from the washer 4 by the rotation of the nut member 5, as shown in FIG. 6 (B). As shown by the arrow, the washer 4 is pressed downward in the drawing, and the washer 4 is pressed in the direction of the object to be fastened 3, so that the frictional force between the washer 4 and the object to be fastened 3 is enhanced. On the other hand, the nut member 5 is forcibly pressed upward in the drawing as shown by an arrow, presses the threads of the nut member 5 and the bolt member 2 against each other, and the frictional force is increased so that the nut member 5 cannot rotate. As a result, the nut member 5 that tends to rotate in the loosening direction due to vibration is stopped. The rotation of the nut member 5 in the loosening direction is stopped when the frictional force is increased by the action of the inclined surface and the nut member 5 reaches an immobile state. When the nut member 5 is rotated by applying vibration in this way, the head joint surface 5b of the nut member 5 and the washer joint surface 4c of the washer 4 are formed on an inclined flat surface. When the bottom portion 5c is displaced, as shown in FIG. 6B, only the top portion 4d of the washer 4 comes into contact with the inclined head joint surface 5b of the nut member 5, and a gap is formed in the other portion. As a result, the joint area between the head joint surface 5b of the nut member 5 and the washer joint surface 4c of the washer 4 becomes smaller, and the frictional force between the two decreases, so that the nut member 5 rotates smoothly due to vibration. As a result, the nut member 5 is separated from the washer 4, so that the locking action is promoted.

When the nut member 5 is screwed into the bolt member 2 to fasten the object to be fastened 3, the indexes 4e and 5d of both are matched, and the washer joint surface 4c and the head joint surface 5b are joined together. However, when the nut member 5 is loosened by the rotary fastener, even if only the nut member 5 is rotated in the loosening direction to be removed, the nut member 5 cannot be rotated by the above-mentioned anti-loosening action. When removing the nut member 5, the rotary fastener is engaged with the engaging portions of both the nut member 5 and the washer 4 and rotated together, so that the nut member 5 can be rotated and removed in the same manner as a normal nut. ..

FIG. 8 shows a second embodiment of the anti-loosening fastening structure according to the present invention, and shows a state in which the object to be fastened is fastened by a bolt member. For example, a blind hole 10a is formed in the substrate 10 made of a metal plate, and a female screw portion 10b is formed in the inner circumference. A male screw portion 11a of the bolt member 11 is screwed into the blind hole 10a. The substrate 10 on which the blind hole 10a is formed is equivalent to a nut member with respect to the bolt member 11. In the present invention, the substrate 10 shown in FIG. 8 and the screw hole penetrating the substrate 10 (not shown). Is also defined as a nut member.

A body to be fastened 3 having a through hole 3a formed is superposed on the substrate 10, and a bolt member 11 is inserted through the substrate 10. As shown in FIG. 9, the bolt member 11 has a seating surface under the neck of the head portion 11b, which is 1.0 to 3.0 more than the lead angle θ2 of the male screw of the bolt member 11 as in the nut member 5 described above. A head joint surface 11c set to a double inclination angle is formed. On the other hand, as shown in FIG. 9, the washer 4 which is fitted into the male screw portion 11a of the bolt member 11 and is interposed between the body to be fastened 3 and the bolt member 11 is configured in the same manner as in the above-described embodiment and is fastened. The washer surface 4b to be joined to the body 3 is formed on a plane perpendicular to the axes of the bolt member 2 and the nut member 5, and the washer joint surface 4c opposite to the seat surface 4b is the head joint surface of the bolt member 11. It is formed at the same angle as the inclination angle θ1 of 11c.

Further, the head portion 11b and the washer 4 of the bolt member 11 are formed in a hexagonal shape, for example, in the same manner as in the above-described embodiment, so that each side thereof is an engaging portion. This engaging portion is engaged with a rotary fastener such as a spanner or a wrench. Further, on the side surface of the head portion 11b of the bolt member 11 and the side surface of the washer 4, as in the above-described embodiment, notch shapes or indicators 11d and 4e for positioning by applying paint are formed. ing.

Next, the anti-loosening action of the anti-loosening fastening structure according to the second embodiment of the present invention described above will be described. As shown in FIG. 8, when the object to be fastened 3 is fastened to the substrate 10 by the bolt member 11, the bolt member 11 first rotates in the loosening direction due to external vibration. As described with reference to FIG. 7, this has a wide friction area F1 in the surface-bonded state between the seat surface 4b of the washer 4 and the object to be fastened 3, whereas it is formed on the bolt member 11 and the substrate 10. This is because the friction area F2 due to the joining of the blind hole 10a with the female screw portion 10b is a fraction or less, so that the bolt member 11 having a small frictional force rotates. At this time, the seat surface 4b of the washer 4 and the object to be fastened 3 have a large frictional force, so that the immovable state is maintained.

After that, when the bolt member 11 tries to rotate due to the application of vibration, the bottom portion 11e of the head joint surface 11c of the bolt member 11 tries to climb the inclined surface with respect to the top portion 4d of the washer 4, so that the bolt member 11 Presses the washer 4 toward the fastened body 3 in an attempt to separate it from the washer 4, further increasing the frictional force between the washer 4 and the fastened body 3. On the other hand, since the bolt member 11 is forcibly pressed upward in the opposite drawing, the threads of the bolt member 11 and the female threaded portion 10b of the substrate 10 are pressed in the axial direction, so that the frictional force is increased and the rotation is increased. It becomes immobile. As a result, the bolt member 11 that tries to rotate in the loosening direction due to vibration cannot rotate in the loosening direction. As a result, the rotation of the bolt member 11 in the loosening direction is stopped when the frictional force is increased by the action of the inclined surface and the bolt member 11 reaches the immobile state. When the bolt member 11 is rotated by applying vibration in this way, the head joint surface 11c of the bolt member 11 and the washer joint surface 4c of the washer 4 are formed on an inclined flat surface, so that the bolt member 11 When the bottom portion 11e is displaced, only the top portion 4d of the washer 4 comes into contact with the inclined head joint surface 11c of the bolt member 11, and a gap is formed in the other portion. As a result, the joint area between the head joint surface 11c of the bolt member 11 and the washer joint surface 4c of the washer 4 is reduced, and the frictional force between the two is reduced, so that the bolt member 11 rotates smoothly due to vibration. As a result, the bolt member 11C is separated from the washer 4, so that the anti-loosening action is promoted.

When the bolt member 11 is loosened by the rotary fastener, the rotary fastener is usually engaged with the engaging portions of both the bolt member 11 and the washer 4 and rotated together, as in the above-described embodiment. It can be removed by rotating it in the same way as the bolt.

FIG. 10 shows a third embodiment of the anti-loosening fastening structure according to the present invention, and is a locking portion that locks the head joint surface of the fastener and the washer joint surface of the washer with respect to the tightening direction of the fastener. Is formed in one place each. The nut member 5 and the washer 4 shown in FIG. 10 are substantially the same as the above-described configuration, and the nut member 5 is formed on a plane inclined on the head joint surface 5b to be joined to the washer 4 of the head 5a. There is. Further, the washer 4 has a flat surface inclined at the same angle as the inclination angle of the head joint surface 5b of the nut member 5 on the washer joint surface 4c opposite to the washer surface 4b to be joined to the object to be fastened 3. .. Therefore, the difference from the nut member 5 described above is that one locking portion 5g is formed on the inclined head joint surface 5b, and the locking portion is also formed on the inclined washer joint surface 4c of the washer 4. It means that 4 g was formed in one place. As shown in FIG. 10, the locking portion 5g of the nut member 5 is formed on the thinnest bottom portion 5c of the head joint surface 5b, and the locking portion 4g of the washer 4 is formed on the thickest top portion 4d of the washer joint surface 4c. Although illustrated so as to be formed, the positions of the locking portions 4g and 5g may be other positions as long as the head joint surface 5b and the washer joint surface 4c are surface-bonded.

As shown in FIGS. 10 and 11, the locking portions 4g and 5g are steps formed on the head joint surface 5b and the washer joint surface 4c, and are formed so that the vertical surfaces of the steps face each other and come into contact with each other. Has been done. In order to form such a step, the inclined flat surface of the head joint surface 5b of the nut member 5 and the inclined flat surface of the washer joint surface 4c of the washer 4 form a step at the locking portion 4g and 5g. It has a tilt angle like this.

When the locking portions 4g and 5g of the head joint surface 5b of the nut member 5 and the washer joint surface 4c of the washer 4 are formed in this way, first, the washer 4 is inserted into the bolt member 2 and the washer surface 4b is fastened. Join to body 3. Next, when the nut member 5 is screwed into the bolt member 2 and the head joint surface 5b is rotated while approaching the washer joint surface 4c of the washer 4, the locking portion 4g of the washer 4 is engaged with the locking portion of the nut member 5. 5 g abuts as shown in FIG. 12 (A). The position where the locking portions 4g and 5g are in contact with each other is determined to be the optimum position where the entire circumference of the head joint surface 5b and the washer joint surface 4c is surface-bonded as shown in the figure. The illustrated nut member 5 is for a right-hand screw that is widely used, and when the nut member 5 is tightened, it is rotated clockwise as shown by an arrow. Therefore, the locking portion 5g of the nut member 5 and the locking portion 4g of the washer 4 are formed in a direction in which the nut member 5 is locked when it is rotated clockwise. By rotating and tightening the nut member 5 from this state, the seat surface 4b of the washer 4 is joined to the fastened body 3 in a pressure contact state. When the nut member 5 is for a left-handed screw, the directions of the locking portions 4g and 5g of the head joint surface 5b of the nut member 5 and the washer joint surface 4c of the washer 4 are reversed.

When vibration is applied from the state where the object to be fastened 3 is fastened by the nut member 5, the nut member 5 is loosened in the loosening direction as shown by the arrow shown in FIG. 12B, as in the first embodiment described above. It rotates in a certain counterclockwise direction. At this time, the washer 4 does not rotate due to vibration due to the large friction area between the washer 4b and the object to be fastened 3. After that, when the nut member 5 tries to rotate counterclockwise due to the application of vibration, the head joint surface 5b of the nut member 5 becomes an inclined surface. Therefore, as shown in FIG. 12B, the nut member The washer 4 is pressed downward in the drawing in an attempt to be separated from the washer 4 by the inclined surface, and the washer 4 is pressed in the direction of the fastened body 3 as shown by the arrow, so that the washer 4 and the fastened body 3 rub against each other. The force is increased. On the other hand, the nut member 5 is forcibly pressed upward in the drawing as shown by an arrow, presses the threads of the nut member 5 and the bolt member 2 against each other, and the frictional force is increased so that the nut member 5 cannot rotate. As a result, the nut member 5 that tends to rotate in the loosening direction due to vibration is stopped. The rotation of the nut member 5 in the loosening direction is stopped when the frictional force is increased by the action of the inclined surface and reaches an immobile state, and the nut member 5 is prevented from loosening any more. At this time, when the rotation distance of the nut member 5 due to vibration is large, as shown in FIG. 12B, the locking portions 4g and 5g that were initially in contact with each other are slightly separated.

13 to 15 show a fourth embodiment of the anti-loosening fastening structure according to the present invention, in which engaging portions with which the rotary fasteners are engaged are formed on the head of the fastener and the peripheral edge of the seat. Each of the engaging portions is formed in a substantially C shape in which the dimensions of the planes of the side surfaces formed on the left and right are made smaller on one side and greatly different on the other side, and the rotary fasteners are formed on the left and right sides of the engaging portion. It is formed in a substantially C shape that engages with the side surface of the rotary fastener, and has an engaging surface that allows insertion from one side of the rotary fastener and prevents insertion from the other side.

As described above, when the washer 4 and the nut member 5 are joined, the thickest top 4d of the washer joint surface 4c of the washer 4 and the thinnest bottom 5c of the head joint surface 5b of the nut member 5 are aligned and the washer joint surface. It is necessary that the 4c and the head joint surface 5b are surface-bonded. In the examples shown in FIGS. 4 and 5 described above, positioning indexes 4e and 5d are provided on the washer 4 and the nut member 5 in order to position and face-join the two. However, since the washer 4 and the nut member 5 are visually positioned, the workability at the time of tightening the nut member 5 may be hindered, and the two may be displaced at the time of tightening. In order to solve this problem, in the fourth embodiment, the engaging portion between the washer 21 and the nut member 20 is deformed so that positioning can be performed almost automatically.

As shown in FIG. 13, the head of the nut member 20 is formed in a substantially hexagonal shape, but the engaging portions 20a formed on the left and right have the dimensions of the planes on the side surfaces smaller on one side and smaller on the other side. It is formed in a roughly C-shape with a large difference. That is, the left and right planes are formed in a substantially C shape by making the dimension L2 between the planes below the drawing smaller than the dimension L1 between the planes above the drawing. On the other hand, as shown in FIG. 14, the washer 21 is formed in a substantially hexagonal shape having the same shape as the nut member 20, but the engaging portions 21a formed on the left and right have the dimensions of the planes on one side. Is formed in a substantially C shape with a small size and a large difference on the other side. That is, the left and right planes are formed in a substantially C shape by making the dimension L4 between the planes below the drawing smaller than the dimension L3 between the planes above the drawing. The engaging portion 20a of the nut member 20 and the engaging portion 21a of the washer 21 are the same, and the dimensions L1 and L3, and the dimensions L2 and L4 are formed to have the same dimensions.

Further, as the rotary fastener 22, the spanner (or wrench) shown in FIG. 15 is exemplified. This rotary fastener 22 is substantially the same as a well-known spanner, but the inner wall facing the diameter portion 22a provided at the tip of the handle 22b is engaged with the engaging portion 20a of the nut member 20 and the washer 21. It is formed in the same substantially C shape as the joint portion 21a.

When performing the tightening work using the rotary tightening tool 22, first, the engaging portions 20a and 21a of the nut member 20 and the washer 21 are made to substantially match, and then, as shown in FIG. 15A, a small flat surface is used. The diameter portion 22a of the rotary fastener 22 is inserted into the nut member 20 and the washer 21 from the directions in which the dimensions are L2 and L4. As a result, the inner wall of the diameter portion 22a formed in a substantially C shape of the rotary fastener 22 joins the nut member 20 and the washer 21 to the engaging portions 20a and 21a even if they are slightly displaced in the rotational direction. Since the washer 21 is forcibly rotated so as to be performed, the nut member 20 and the washer 21 are positioned and surface-joined. After that, the rotary fastener 22 is rotated to perform the tightening work of the nut member 20. Even during this tightening operation, the positions of the nut member 20 and the washer 21 in the rotational direction are determined by the diameter portion 22a of the rotary fastener 22, so that the washer 21 can be pressed against the object to be fastened 3 with a predetermined pressure. it can.

On the other hand, when the rotary fastener 22 is inserted from the directions of the dimensions L1 and L3 between the large planes, the diameter portion 22a of the rotary fastener 22 is substantially C-shaped as shown in FIG. 15B. Since it is formed in a shape, it cannot be inserted into the engaging portions 20a and 21a of the nut member 20 and the washer 21. Therefore, the rotary fastener 22 is allowed to be inserted only when the nut member 20 and the washer 21 are in the correct positions, and cannot be inserted in an improper state. Therefore, the nut member 20 and the washer 21 are in the offset state at the correct position in the face-joined state. It is possible to make it.

FIG. 16 shows another example of the rotary fastener, in which the diameter portion is formed in a substantially annular shape. The rotary fastener 23 is formed in a shape in which the diameter portion 23a is allowed to be inserted into the engaging portions 20a and 21a of the nut member 20 and the washer 21. Then, when performing the tightening work using the rotary tightening tool 23, after the engaging portions 20a and 21a of the nut member 20 and the washer 21 are aligned, the diameter portion 13a of the rotary tightening tool 23 is inserted from above. .. At this time, when the positions of the engaging portions 20a and 21a of the nut member 20 and the washer 21 are aligned, the rotary fastener 23 is engaged with both, and if they are not aligned, the insertion is prevented, so that the nut member 20 and the nut member 20 The positioning state of the washer 21 can be determined. After the rotary fastener 23 is engaged with both of them, it is rotated to perform the tightening work of the nut member 20.

FIG. 17 shows a fifth embodiment of the anti-loosening fastening structure according to the present invention, in which an adhesive film of a temporary fixing adhesive is applied between the head joint surface of the fastener and the washer joint surface of the washer. , The surface joint state of the head joint surface and the washer joint surface before tightening with the rotary fastener is maintained. The nut member 5 and the washer 4 as the fastener have the same configuration as shown in FIGS. 1 to 3 described above, and the nut member 5 is inclined to the head joint surface 5b to be joined to the washer 4 of the head 5a. It is formed on a flat surface. Further, the washer 4 has a flat surface inclined at the same angle as the inclination angle of the head joint surface 5b of the nut member 5 on the washer joint surface 4c opposite to the washer surface 4b to be joined to the object to be fastened 3. ..

As described above, when the washer 4 and the nut member 5 are joined, the thickest top 4d of the washer joint surface 4c of the washer 4 and the thinnest bottom 5c of the head joint surface 5b of the nut member 5 are aligned and the washer joint surface. It is necessary that the 4c and the head joint surface 5b are surface-bonded. Therefore, an adhesive film 30 for temporary fixing is applied between the head joint surface 5b of the nut member 5 and the washer joint surface 4c of the washer 4, and the thickest top 4d of the washer joint surface 4c of the washer 4 is formed. In a state where the thinnest bottom portion 5c of the head joint surface 5b of the nut member 5 is previously aligned, the head joint surface 5b and the washer joint surface 4c are held so as to be in a surface joint state. When the tightening operation is performed by a rotary tightening tool made of a spanner or a wrench, the nut member 5 and the washer 4 are rotated at the same time, so that both are tightened in a coincident state.

As the temporary fixing adhesive to which the adhesive film 30 is applied, an aqueous adhesive containing a vinyl acetate resin as a component, a water-soluble polyvinyl alcohol (PVAL), or an adhesive for paper containing starch as a main component is preferable. It is desirable that the adhesive can be stretched to form an ultrathin adhesive film 30, and that the adhesive loses its viscosity in a solidified state. This is to prevent the viscosity of the adhesive from hindering the sliding of the head joint surface 5b and the washer joint surface 4c. When vibration is applied, the head joint surface 5b and the washer joint surface 4c slide, so that the nut member 5 rotates in the loosening direction. Therefore, as described above, the nut member 5 rotates in the loosening direction. However, due to the action of the inclined surface, the frictional force is increased and the nut becomes immobile. In the tightened state, the adhesive between the head joint surface 5b and the washer joint surface 4c is discharged due to the strong pressing force of the nut member 5, but even if a small amount remains, the adhesive is discharged. If a pressing force for pressing the washer 4 in the direction of the object to be fastened 3 and a pressing force for pressing the threads of the nut member 5 and the bolt member 2 are obtained, the loosening prevention effect is not hindered.

In the present invention, suitable examples have been described. In addition to this example, in the embodiment shown in FIG. 1, a through hole 3a is formed in the substrate 1 and a general bolt member 2 is inserted through the substrate 1, but a threaded portion of the bolt member is formed in the through hole 3a formed in the substrate 1. The base end portion is caulked and fixed, or welded and fixed, and the substrate 1 is defined as the head of the bolt member, which is defined as the bolt member in the present invention.

Although the present invention has been specifically described above based on the examples, it goes without saying that the present invention is not limited to the above examples and can be variously modified without departing from the gist thereof. Bolts and nuts can be applied to and are not limited to JIS screws and inch screws.

The present invention can be applied to fastening members to be fastened used in machinery / equipment, electrical machinery / equipment, vehicles, construction, construction, railways, and the like.

1 Board 2 Bolt member 2a Threaded part 3 To be fastened 4 Washer
4a Through hole 4b Seat surface 4c Washer joint surface 4e Index 4d Top 5 Nut member 5a Head 5b Head joint surface 5c Bottom 5e Index θ1 Tilt angle θ2 Lead angle C Axis

Claims (2)

It is a fastening structure in which a fastener composed of a bolt member and a nut member is screwed to fasten the object to be fastened.
A washer is interposed between the head of the fastener and the body to be fastened.
The seat surface of the washer that is surface- joined to the object to be fastened is formed in a plane perpendicular to the axis, and the opposite washer joint surface is formed in an inclined plane and a top is formed, and the bolt is formed in the center. A through hole is formed to penetrate the member,
When the washer joint surface opposite to the washer seat surface and the head joint surface formed on the head itself of the fastener to be joined to the washer joint surface are formed on a plane inclined at the same angle as the washer joint surface. At the same time, a bottom portion is formed on the head joint surface, and the inclination angle of these planes is formed to be 1 times the lead angle of the male screw portion of the object to be fastened and the female screw portion of the nut member.
A locking structure for preventing loosening, wherein the friction area of the seat surface of the washer that is surface-bonded to the object to be fastened is formed to be larger than the friction area of the male screw and the female screw of the fastener. Engagement portions with which the rotary fasteners are engaged are formed on the head of the fastener and the peripheral edge of the seat, and each of the engaging portions has the dimensions of the planes of the side surfaces formed on the left and right sides. The rotary fastener is formed in a substantially C shape with a small side and a large difference in the other side, and the rotary fastener is formed in a substantially C shape to engage with the left and right side surfaces of the engaging portion and has an engaging surface. The locking structure according to claim 1, wherein the rotary fastener is allowed to be inserted from one side and cannot be inserted from the other side.