JPH0276919A - Tightening method by preventing bolt and nut from being loosened - Google Patents

Abstract

PURPOSE:To prevent a nut from being loosened from a bolt by contacting the ring projected section of a convex nut with the slant projected section of a washer or the slant recessed section on the periphery of a bolt hole opening in the article to be tightened and screwing the convex nut onto the bolt to contact the projected nut. CONSTITUTION:A ring projected section 13 of a projected 1 is contacted with a slant reccessed section 21 of a washer 2 and the nut 1 is screwed onto a bolt 3. As the section 13 of the nut 1 is pressed against the section 21 of the washer 2, a split section 11 of the nut 1 is contracted and the whole nut 1 is contracted to tighten the bolt 3. Since the outer surface of the section 13 of the nut 1 is formed in spherical shape, the section 13 and the section 21 of the washer 2 are contacted with each other evenly on the periphery.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fastening method using bolts and nuts that prevents loosening of the nuts due to external forces such as vibrations after fastening, and the fastening method. This invention relates to nuts and washers used in the method.

[Conventional technology]

The biggest drawback of fastening with bolts and nuts is that they loosen after they are installed and fastened, and various types of locking pads have been devised to prevent this. For example, Jikosho 3
No. 1-1634, as well as Utility Model Publication No. 31-1635 and Utility Model Publication No. 36-32513, as shown in FIG. , the convex nut b is cut along the axial direction, and the cut surfaces of several separate pieces are formed with adhesive, and the convex nut b is a cone into which the leg part a is inserted. It is a double nut which is arranged opposite to a concave nut l-e having a shaped concave part d and is screwed onto a bolt f, and the conical leg part a of the convex nut b is connected to the conical concave part d of the concave nut e. There is one in which the entire convex nut I-b shrinks as it penetrates into the bolt, and the thread carved on its inner surface bites into the thread of the bolt, thereby tightly connecting the two. Also, the Nando shown in Design Registration No. 246707 is made by inserting many incisions i into the top surface of the Nando h to form a reflection part j, as shown in Fig. 11, and compressing this part in the axial direction to form a steel material. When the bolt is screwed in, it generates pressure in the reflection part j and tightens it, thereby producing a loosening effect.

[Problems to be Solved by the Invention] However, in the double nand as shown in FIG. There is a problem that it takes In addition, in the case where a reflection part j is provided as shown in Fig. 11, only one nara 1- is used, but
When screwing the bolt, the resistance due to the reflection part j is large and it is difficult to screw in by hand. Even when temporarily tightening, it is necessary to use a tool such as a wrench from the beginning and tighten the nut further after the bolt is fixed. It was necessary to screw them together using a tool, which resulted in poor workability.

By the way, loosening of screws includes (1) Non-rotational slack, that is, slack that is not caused by the return rotation of the nut but is caused by the settling of unevenness of the seat surface, etc. (2) There is slack due to rotation, that is, slack due to rotation of the nut due to external force such as vibration. In the former case, this can be prevented by stopping the loosening at a certain point or by retightening it, but in the latter case, where the loosening is due to vibration, it is difficult to prevent this and other parts may need to be tightened. The only way to prevent loosening is to use a labor-intensive method such as attaching or gluing. The devices shown in FIGS. 10 and 11 are intended to prevent such loosening. A major factor in the loosening of the nut due to vibrations, etc. is the non-uniformity of the seat pressure. That is, any vibrations applied to the nut will eventually result in horizontal sliding motion of the seat surface, but if the pressure distribution on the seat surface is not uniform at this time, frictional resistance will be concentrated in the area of maximum pressure. However, a nut has a donut-shaped seating surface in the center to allow the bolt to pass through, and if one part of the nut is strongly pressurized, the pressure on the opposite side will be small.
The pressure distribution on the seat surface becomes non-uniform. After the bolt and nut are fastened, the force acting to loosen them is the force applied from all directions, up and down, left and right, due to vibrations, thermal expansion, etc., and is only the force in the direction that tries to rotate the nut. In this case, only horizontal movement occurs between the surface of the fastened object and the seat surface of the nut.

In this case, the nut seating surface slides back and forth on the surface of the object to be fastened while being in pressure contact with the surface. At this time, if there is an uneven pressure distribution on the seat surface as described above, for example, if greater pressure is applied to a part of the left side of the front and back, the frictional resistance of this part will be greater than that of the right part. For,
When the seat is pushed forward, if the screw is right-handed, it will try to rotate in the tightening direction, and when it is pushed back, it will rotate in the loosening direction. However, because a screw inherently has greater resistance to movement in the direction of tightening than resistance to movement in the direction of loosening, even if the seat is moved an equal distance back and forth, the rotation in the direction of loosening is greater, resulting in The screws will eventually loosen. Normally, when a screw is tightened, the male thread and the female thread are pressed against each other, and the frictional force generated between the two resists the force in the loosening direction of the screw, so that the screw does not loosen. However, tightening can cause problems such as sagging, sinking, galling, or cracks between the plates to be fastened due to waving, warping, or curling of the plates, dripping during painting, etc.
Due to uneven peeling of the paint film and foreign substances entering the gaps, the stress of the tightening torque applied to the bearing surface is unevenly applied to the threaded surface of the bolt and the bearing surface of the nut. Non-uniform pressure distribution on the surface, ie non-uniform frictional resistance, causes the nut to loosen and rotate. In addition to the disadvantages of tightening in this manner, the bearing surface of the nut must be perpendicular to the shaft in order to even out the pressure distribution on the bearing surface, but bolts and nuts Since the fastening method uses a spiral thread, there is essentially no left-right imbalance, and the threaded hole may be unavoidably provided at a slight angle due to the design, or the threaded hole may be tilted due to the precision of the workmanship. However, the pressure distribution on the nut seating surface tends to be uneven, which causes the nut to loosen.

The present invention relates to the loosening of nuts when fastening bolts and nuts, and solves the problems with the conventional fastening methods as described above, as well as the non-uniformity of the pressure distribution on the nut seating surface, which is a major cause of the loosening inherent in nuts. In view of this, it is an object of the present invention to provide a fastening method using bolts and nuts that can save labor during fastening and reliably prevent loosening after fastening without increasing costs.

[Means to solve the problem]

In order to achieve the above object, the fastening method using bolts and nuts according to the present invention has an annular convex portion formed on the seat surface with a spherical outer circumferential surface and a cut portion on one side, or at least the annular convex portion is provided on one side. A convex nut having at least two longitudinal grooves at a position including the convex portion and a washer having an inclined concave portion that receives the annular convex portion of the convex nut, or an opening in a bolt hole of the object to be fastened. A convex nut is formed by providing a slanted concave portion on the edge, and by screwing the bolt with the annular convex portion of the convex nut facing the slanted concave portion of the washer or the slanted concave portion of the bolt hole opening edge of the object to be fastened. It is characterized by being able to narrow down. Furthermore,
In order to more reliably generate torque, that is, axial force, and a loosening effect when tightening with bolts and nuts as described above, it is necessary to adjust the bolt axis line of the inclined surface of the inclined recess at the opening edge of the washer or bolt hole. It is preferable that the angle with respect to the recess becomes smaller toward the bottom of the recess.

[For production]

The fastening method using bolts and nuts according to the present invention is configured as described above, and as the bolt is screwed into the convex nut and tightened, the annular convex part of the convex nut and the washer or the bolt hole opening edge of the object to be fastened are connected. The convex nut becomes narrower as it fits deeper into the recess provided in the convex nut, and by tightening the bolt, loosen rotation between the bolt and nut is prevented, and the annular convex portion of the convex nut has a spherical outer peripheral surface. For example, in the case of conventional bolt and nut fastening, the nut has a 1° tapped hole 15 as shown in Figure 8 (a).
If the bolt 3 is provided obliquely to the bolt axis, or if the axis of the bolt 3 is inclined to the fastened object 4 as shown in Fig. 8 (b), the nut 1° and washer 2° or the surface of the object to be fastened 4 does not make complete contact, resulting in uneven pressure distribution and easily loosening due to external forces such as vibrations. However, in the present invention, as shown in FIG. Even when the hole 15 is oblique (Fig. 8 (a)) or the axis of the bolt 3 is inclined (Fig. 8 (b)), the annular convex portion 13 of the convex nut 1 By uniformly contacting the inclined surface of the inclined recess 21 of the washer 2 over the entire circumference of the surface, there is no uneven pressure distribution on the seat surface, and the pressure distribution on the nut seat surface is improved even when external forces such as vibrations are applied. Due to the non-uniformity of the nut, rotation and loosening of the nut can be more reliably prevented.

Furthermore, when tightening bolts and nuts, it is necessary to generate sufficient axial force (torque for tightening in the axial direction of the bolt), and the nut may shrink before this axial force is generated. If the bolt cannot rotate relative to the bolt, the generation of axial force will be insufficient. Therefore, the inclined surface of the inclined recess 21 provided at the bolt hole opening of the washer 2 or the object to be fastened 4 is formed into a spherical shape as shown in FIG. By forming it so that it stands up,
As shown in FIG. 9(A), when the engagement between the annular protrusion 13 of the nut 1 and the recess 21 of the washer 2 is shallow at the beginning of screwing, the seat surface of the nut 1 is aligned with the inclined surface of the recess 21 of the washer 2. Of the force F received from the contact portion of As the convex portion 13 of the washer 1 enters the concave portion 7 of the washer 2 and the engagement between the two becomes deeper, the nut 1 becomes smaller and acts in the horizontal direction as shown in FIG. 8 (b), tightening the bolt. By increasing the force f2, the increase in axial force is large at the beginning of screwing, and after sufficient axial force is generated by fastening, by further tightening, the bolt tightens due to the tightening of the nut. By setting the force to increase, it is possible to prevent the bolt from being tightened by the nut before sufficient axial force is generated, making rotation between the two impossible and resulting in insufficient axial force generation. .

〔Example〕

Examples will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a nut 1 used in the fastening method using bolts and nuts according to the present invention, in which one side of the nut l is cut to form a cut portion 11, and the cut portion 11 is A vertical cut groove 12 is formed on the inner surface of the opposite side to enable narrowing. Also, Natsu 1
An annular convex portion 13 having a spherical outer surface is provided on the lower surface of the
is formed as a convex nut. Said convex nut 1
In order to perform fastening using a bolt, as shown in FIG. This uses a washer 2 formed with an inclined recess 21 capable of receiving. Then, by disposing the annular convex portion 13 of the convex nut 1 and the inclined concave portion 21 of the washer 2 and screwing the bolt 3 together, the annular convex portion of the convex nut 1 is screwed together. As the fitting between the portion 13 and the inclined recess 21 of the washer 2 deepens, the width of the cut portion 11 of the convex nut 1 decreases, and the convex nut 1 becomes narrower as a whole. is prevented. Furthermore, in the above-mentioned fastening using bolts and nuts, since the outer surface of the annular convex portion 13 of the convex nut l is formed into a spherical shape, the annular convex portion 13 and the inclined concave portion 21 of the washer 2 are completely connected to each other. Uniform contact over the circumference prevents uneven pressure distribution, and loosening due to external forces such as vibrations can be reliably prevented.

In the above case, the annular convex portion 1 of the convex nut 1
3 and the inclined recess 21 of the washer 2, that is, the angle of inclination of the inclined recess 21 of the washer 2 is preferably about 25 to 30 degrees with respect to the bolt axis. As the contact angle increases, the pressure on the nut seating surface increases and the axial force generated by fastening increases, and as the contact angle becomes less inclined with respect to the bolt axis, the nut becomes smaller and the force that clamps the bolt increases, making it more effective at preventing loosening. is large, and the contact angle, that is, the inclination angle of the inclined recess 21 of the washer 2 may be set as appropriate depending on the application. For example, if the object to be fastened is made of a relatively soft material such as wood or aluminum, the contact angle, that is, the angle of inclination of the inclined recess 21 with respect to the bolt axis, may be set to be relatively small to prevent excessive fastening. The generation of axial force prevents damage to the object to be fastened, and also makes it possible to firmly tighten the bolt 3 with the nut 1 and effectively prevent loosening.

Further, it is preferable that the width of the cut portion 11 is set to such a degree that a slight gap remains when the bolt is fastened.

Further, the inclined recess 21 of the washer 2 is formed into a convex spherical shape as shown in FIG. 3, and the angle of inclination with respect to the bolt axis becomes smaller as the recess 21 goes downward. After generating sufficient axial force to fasten the objects to be fastened at the beginning of the connection, as the annular convex part 13 of the convex nut 1 formed in a spherical shape is deeply fitted into the concave part 21, the bolt axis By causing the convex nut 1 to tighten the bolt 3 by increasing the acting force of constriction in the direction, the convex nut 1 decreases and tightens the bolt 3 before sufficient axial force is generated, making it impossible to rotate. This can prevent insufficient axial force.

Furthermore, in the present invention, instead of using the washer 2, as shown in FIG. By providing the inclined recess 42, it is possible to fasten bolts and nuts while preventing loosening.

5 and 6 show other embodiments of the convex nut 1 used in the present invention, in which an annular convex portion 13 of the nut 1 is formed instead of forming a cut portion in the nut 1. Vertical grooves 14 are formed at two or more positions including
3 fits into an inclined recess provided in the washer 2 or the object to be fastened 4, the convex nut 1 becomes smaller and the bolt can be tightened. In this way, the convex nut 1 is not limited to those of the above embodiments, and the convex nut 1 can be formed by fitting the annular convex portion 13 provided on the lower surface into the inclined concave portion of the washer or the object to be fastened. 1 may be made into a shape that can narrow down. In this case, the more grooves 14 are provided, the easier the nut l will become narrower.
The number of grooves may be appropriately set depending on the material of the object to be fastened and other various conditions. For example, if the object to be fastened is made of a relatively soft material such as wood or aluminum, by setting a large number of grooves 14, excessive axial force will be generated and the object to be fastened will be damaged. In order to prevent this, the bolt 3 is securely tightened with the nut 1 to produce a loosening effect, and when the object to be fastened is relatively hard and durable such as a steel plate, the number of grooves 14 is It is also possible to increase the axial force by decreasing the axial force.

Experiments The results of axial force (torque) tests and vibration tests using the above-mentioned fastening method using bolts and nuts according to the present invention are shown in Attached Tables 1 and 2.

〔Effect of the invention〕

As described above, according to the present invention, one NAND is lightly screwed onto a bolt in the usual manner without using a washer and a nut, or a washer, and the final tightening torque is used to connect the annular protrusion of the nut and the washer or By fitting the inclined recess provided in the object to be fastened at a stable angle, the nut can be tightened even when the screw hole or bolt shaft of the nut is tilted or the surface of the object to be fastened is uneven. It can be fastened without causing uneven pressure distribution on the seat surface,
Furthermore, since the bolt can be tightened with a nut during fastening, it is possible to prevent loosening due to external forces such as vibrations and maintain a secure fastened state. In addition, when loosening the nut, the nut returns to its original state due to elastic deformation, and can be easily removed and reused.

Therefore, according to the present invention, when fastening with bolts and nuts, the single nut eliminates the trouble and high cost of the fastening work required with conventional double nuts, and achieves a loosening prevention effect equal to or greater than that of double nuts. It's Uruchino.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of a nut used in the bolt-nut fastening method according to the present invention, in which (A) is a front view, (B) is a bottom view, and (C) is a view in the bottom view. A longitudinal sectional view taken along the line A-A, FIGS. 2 to 4 are explanatory longitudinal sectional views showing various embodiments of the fastening method using bolts and nuts according to the present invention, and FIG. 5 shows another embodiment of the nut. , (A) is a front view thereof, (B) is a bottom view, (C) is a vertical sectional view taken along the line B-B in the bottom view, and FIG. 6 shows still another embodiment of the nut. , (a) is its front view,
(B) is a bottom view, (C) is a cross-sectional view taken along line C-C in the front view, FIG. 7 is an explanatory diagram of the fastened state of bolts and nuts in the present invention, and FIG. 8 is a bolt and nut in the conventional method. Figures 9 (a) and 9 (b) illustrate the state in which axial force and bolt tightening force are generated due to changes in the fitted state between the washer's inclined recess and the nut's annular protrusion. The explanatory drawings, FIGS. 10 and 11, show a conventional locking nut. l: Convex nut, 11: Cut portion, 13: Annular convex portion, 1
4: Cut groove, 2: Washer, 21: Slanted recess, 3:
Bolt, 4: Object to be fastened, 42: Inclined recess. Attached Table 2 Vibration Test Note) Nut: M12X1.75 Bolt: SCM3, thread accuracy grade 2 Test method: After tightening the specimen to the torque value shown in the table, the test was conducted under the vibration conditions shown below. Testing machine: NS type high speed screw slack tester Vibration conditions: Vibration frequency: 30H2 vibration table Stroke: 11M Impact stroke: 19m Vibration direction: Vertical Figure 7 Figure 8 Figure 6 Figure 5 Figure 10 Figure 11 Figure 9 (a) (b)

Claims (1)

[Scope of Claims] 1) The seat surface has an annular convex portion having a spherical outer peripheral surface, and a cut portion is provided on one side, or at least two vertically extending portions are provided at a position including the annular convex portion. A convex nut having a kerf and a washer having an slanted recess for receiving the annular convex portion of the convex nut, or a slanted recess is provided at the opening edge of the bolt hole of the object to be fastened, and the convex nut The convex nut can be narrowed by disposing the annular convex portion of the nut in opposition to the inclined concave portion of the washer or the inclined concave portion of the bolt hole opening edge of the object to be fastened, and then screwing the bolt together. A fastening method using bolts and nuts that prevent loosening. 2) A method for preventing loosening as set forth in claim 1, wherein the inclined recess is formed at the opening edge of the washer or the bolt hole, and the angle of the inclined surface with respect to the bolt axis decreases as it goes downwards of the recess. Fastening method using bolts and nuts. 3) The seat surface has an annular protrusion formed by forming the outer peripheral surface into a spherical shape, and a cut part is provided on one side, or at least two longitudinal grooves are provided at a position that includes the annular protrusion. A nut. 4) A washer characterized in that an inclined recess is formed at the opening edge of the bolt insertion opening, and the angle of inclination of the inclined surface with respect to the bolt axis decreases as it goes downward.