JP5953420B1 - Fastener and fastening method thereof - Google Patents

Abstract

To provide a novel fastener capable of reliably preventing a nut from loosening with a simple structure. A bolt 10 and a nut 20 are provided, and a long hole 13 for injecting a coolant into a shaft portion of a screw portion 12 of the bolt 10 is provided, and the outer diameter of the screw portion 12 is set to an inner diameter of the nut 20 in a normal temperature range. Larger than. Then, if a coolant is injected from the elongated hole 13 of the bolt 10 to cool the screw portion 12 and thermally contract in the radial direction, and then the nut 20 is screwed, then the screw portion 12 is thermally expanded and the nut 20 Screw it tightly so that it pushes in and spreads. As a result, the nut 20 is not loosened. Further, since the structure is simple, the manufacturing cost is low. [Selection] Figure 1

Description

  The present invention relates to a fastener for preventing loosening of a nut screwed to a bolt and a fastening method thereof.

  Bolts and nuts that are indispensable for constructing steel structures and machinery and equipment may loosen or fall off due to long-term vibration. As a method of preventing such a nut from loosening, for example, a method of using a spring washer or the like, such as bonding a nut screwed to a bolt with an adhesive, connecting a bolt and a nut with a split pin, is known. However, various other methods have been proposed.

  For example, Patent Document 1 below proposes a locking nut that prevents a nut from loosening by using a double nut including an upper nut and a lower nut. Patent Document 2 proposes a fastening body loosening prevention mechanism in which a nut is covered with a cap to prevent the nut from loosening or falling off. Further, Patent Document 3 proposes a nut / bolt that can exhibit a loosening prevention effect by specially processing the thread surface. Further, Patent Document 4 proposes a locking nut that prevents the nut from loosening by using a friction piece for generating friction torque.

JP 2002-195236 A JP 2005-3068 A JP 2013-249944 A JP2015-102207A

  By the way, all of the conventional methods as described above have a problem that the structure is complicated and the cost is high because a special device is applied to the bolt or the nut itself.

  Therefore, the present invention has been devised to solve these problems, and an object of the present invention is to provide a novel fastener capable of reliably preventing the nut from loosening with a simple structure.

  In order to solve the above-mentioned problem, the first invention comprises a bolt and a nut, has a long hole for injecting a coolant into the shaft portion of the screw portion of the bolt, and has an outer diameter of the screw portion in a normal temperature range. Is a fastener that is larger than the inner diameter of the nut. According to such a configuration, the coolant can be easily fastened by injecting a coolant into the elongated hole of the bolt, thermally shrinking the screw portion in the radial direction, and screwing the nut into the screw portion before thermal expansion. . Further, after that, the threaded portion is returned to room temperature, and is thermally expanded so as to push the nut so as to bite into the thread groove. This prevents the nut from loosening even if vibration is applied to the bolt. Further, since the structure is simple, the manufacturing cost is low. The “normal temperature range” in the present invention refers to a temperature at which an outdoor structure is usually exposed throughout the year, for example, a range of 0 ° C. to 40 ° C. (hereinafter the same).

  According to a second invention, in the first invention, the bolt is any one of SUS301, SUS304, SUS304L, SUS309S, SUS310S, SUS316, SUS316L, SUS317, SUS321, and SUS347. is there. Since these stainless steels have a larger coefficient of thermal expansion than other metal screw materials, the screw thread portion of the bolt strongly bites into the nut due to thermal expansion, and the nut can be prevented from loosening more reliably.

  According to a third invention, in the first or second invention, a coolant is injected into the elongated hole of the bolt to thermally contract the screw portion in the radial direction, and the nut is attached to the screw portion before thermal expansion. It is the fastening method characterized by screwing together. According to such a fastening method, the heat-shrinked bolt and nut can be easily fastened, and when the bolt is subsequently thermally expanded, the threaded portion is firmly screwed into the nut. This prevents the nut from loosening even if vibration is applied to the bolt.

  A fourth invention comprises a bolt, a nut, and an insertion pin, and a long hole for inserting the insertion pin is formed in a shaft portion of the screw portion of the bolt, and when the outer diameter of the insertion pin is at room temperature, the length is long. The fastener is characterized by being larger than the inner diameter of the hole. According to such a configuration, if the insertion pin is cooled to a room temperature or lower, and a nut is screwed into the bolt, and then the insertion pin is press-fitted into the long hole of the bolt, the insertion pin will eventually reach room temperature. As a result, it thermally expands to expand the threaded portion of the bolt. As a result, the threaded portion is screwed tightly so as to push the nut and bite into the thread groove, so that the nut does not loosen even if vibration is applied to the bolt.

  According to a fifth invention, in the fourth invention, the insertion pin is composed of any one of SUS301, SUS304, SUS304L, SUS309S, SUS310S, SUS316, SUS316L, SUS317, SUS321, and SUS347. It is. Since these stainless steels have a larger coefficient of thermal expansion than other metal screw materials, the screw thread portion of the bolt strongly bites into the nut due to thermal expansion, and the nut can be prevented from loosening more reliably.

  According to a sixth invention, in the fourth or fifth invention, the insertion pin is cooled to a room temperature or lower, and a nut is screwed into the bolt, and then the insertion pin is press-fitted into a long hole of the bolt. It is the fastening method characterized by these. According to such a fastening method, if the nut is screwed into the bolt and then the insertion pin is press-fitted into the elongated hole of the bolt, the insertion pin eventually reaches a normal temperature and is thermally expanded, so that the screw portion of the bolt is removed. Expand the diameter. As a result, the threaded portion is screwed tightly so as to push the nut and bite into the thread groove, so that the nut does not loosen even if vibration is applied to the bolt.

  A seventh invention is a fastener having a bolt, a nut, and a press-fit pin, and having a slit for press-fitting the insertion pin in a screw portion of the bolt. According to such a configuration, if the nut is screwed into the bolt and then the press-fit pin is press-fitted into the slit of the bolt, the threaded portion is screwed firmly so that the diameter of the screw expands and the nut is pushed wide. Even when vibration is applied to the bolt, the nut will not loosen. Further, since the structure is simple, the manufacturing cost is low.

  According to the present invention, the threaded portion of the bolt is firmly screwed so as to bite into the threaded groove by expanding the diameter by thermal expansion or the like and pushing the nut. As a result, the nut is not easily loosened even if vibration is applied to the bolt. Further, since the structure is simple, the manufacturing cost is low.

1 is a perspective view showing a first embodiment of a fastener 100 according to the present invention. 4 is an explanatory diagram showing the relationship between the diameter (outer diameter) d1 of the thread of the threaded portion 12 and the diameter (inner diameter) d2 of the thread groove of the nut 20. FIG. It is explanatory drawing which shows the fastening method which concerns on 1st Embodiment. It is a perspective view which shows 2nd Embodiment of the fastener 100 which concerns on this invention. 4 is an explanatory diagram showing the relationship between the diameter d3 of the insertion pin 30 and the diameter d4 of the elongated hole 14 of the bolt 10. FIG. It is explanatory drawing which shows the fastening method which concerns on 2nd Embodiment. It is a perspective view which shows the cooling box 40 which cools the insertion pin 30. FIG. It is a perspective view which shows 3rd Embodiment of the fastener 100 which concerns on this invention. It is explanatory drawing which shows the fastening method which concerns on 2nd Embodiment.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
[First Embodiment]
FIG. 1 is a perspective view showing a first embodiment of a fastener 100 according to the present invention. As shown in the figure, the fastener 100 includes a bolt 10 and a nut 20 that is screwed into the bolt 10. The bolt 10 has a hexagonal bolt head 11 and a screw portion 12 integrated with the hexagonal bolt head 11, and the shaft portion of the screw portion 12 penetrates the bolt head 11 from its tip. A long hole 13 is formed.

The bolt 10 is made of a metal having a thermal expansion coefficient larger than that of other general metals, for example, stainless steel such as SUS301, SUS304, SUS304L, SUS309S, SUS310S, SUS316, SUS316L, SUS317, SUS321, and SUS347. Yes. The average thermal expansion coefficients (10 ⁻⁶ / ° C., 0 to 100 ° C.) of these stainless steels are 16.9 for SUS301, 17.3 for SUS304 and SUS304L, 14.9 for SUS309S, 14.4 for SUS310S, and SUS316. SUS316L and SUS317 are 16.0, SUS321 and SUS347 are 16.7, and about 1.5 times to 2.times higher than other stainless steels and other screw materials such as ordinary steel, carbon steel, alloy steel and the like. It has a high thermal expansion coefficient of about zero.

  Then, the outer diameter d1 (thread) of the threaded portion 12 of the bolt 10 is as shown in FIG. 2 at a normal temperature (for example, in a temperature range of 0 to 40 ° C.). It is slightly larger than the inner diameter d2 of the 20 thread groove, and is equal to or less than the inner diameter d2 of the thread groove so that it can be screwed into the nut 20 by thermal contraction at a low temperature (for example, cooled to −10 to −50 ° C.). It becomes the size that becomes.

  FIG. 3 shows a fastening method of the fastener 100 according to the present invention having such a configuration. First, as shown in FIG. 2A, a spray-type instantaneous coolant is injected into the elongated hole of the bolt 10 before fastening to cool the entire bolt 10 to a temperature below the freezing point, for example, about -10 to 40 ° C. The spray type instantaneous coolant used here is not particularly limited, and commercially available products can be used. For example, if a product (trade name “Loctite (registered trademark) freeze & release”) manufactured by Henkel Japan Co., Ltd. is used, the entire bolt 10 can be cooled to −43 ° C. at a stroke by spraying for several seconds to several tens of seconds. .

  When the bolt 10 is cooled to about −40 ° C. in this way, it has been confirmed that the outer diameter d1 of the screw portion 12 is about 10% smaller than that at normal temperature (for example, 20 ° C.) due to thermal contraction. . Then, if the nut 20 is screwed into the screw portion 12 as shown in FIG. 4B while maintaining this cooling state, the fastening operation can be performed smoothly. Thereafter, if left in that state, the bolt 10 is thermally expanded as the temperature of the bolt 10 rises to the normal temperature range as shown in FIG. 3C, and the outer diameter d1 of the threaded portion 12 gradually becomes the original size. Come back to.

  Since the outer diameter d1 of the screw portion 12 in the normal temperature region is slightly larger than the inner diameter d2 of the screw groove of the nut 20 as described above, the screw portion 12 becomes a screw groove of the nut 20 as the temperature rises. The nut 20 expands so that it gradually bites in, and eventually closes tightly so that the thread groove of the nut 20 is pushed and expanded. As a result, the nut 20 is securely screwed onto the bolt 10, so that the nut 20 is not easily loosened even when vibration is applied to the bolt 10.

  When the nut 20 is removed from this state, if the spray-type instantaneous coolant is sprayed into the elongated hole 13 of the bolt 10 for several seconds to several tens of seconds, the heat shrinks and the outside of the screw portion 12 is removed. Since the diameter d1 becomes small, the nut 20 can be easily removed. In addition, the long hole 13 formed in the bolt 10 may not be penetrated, and may have a structure drilled from the distal end side of the screw portion 12. The bolt 10 is not limited to stainless steel as described above, and may be carbon steel, titanium, aluminum, or other metals or resins.

[Second Embodiment]
Next, FIG. 4 thru | or FIG. 7 shows 2nd Embodiment of the fastener 100 which concerns on this invention. As shown in the drawing, the fastener 100 includes a bolt 10, a nut 20 that is screwed with the bolt 10, and an insertion pin 30. And the long hole 14 is formed in the axial part of the thread part 12 of the volt | bolt 10 so that this may be penetrated, and the said insertion pin 30 is inserted in this long hole 14. As shown in FIG.

  The insertion pin 30 has a distal end portion 31 whose distal end has a slightly tapered diameter, and a flat portion 32 for driving is integrally formed on the top portion, and the overall shape thereof is substantially a nail shape. It has become. And the step part 14a is formed in the bolt head 11 side of the long hole 14 formed in the volt | bolt 10, When this insertion pin 30 is inserted in the long hole 14 from the front-end | tip part 31 side, The flat portion 32 is fitted into the step portion 14a so that the surface thereof is substantially flush.

  As in the first embodiment, the insertion pin 30 has a larger coefficient of thermal expansion than other general metals, such as SUS301, SUS304, SUS304L, SUS309S, SUS310S, SUS316, SUS316L, SUS317, SUS321, It is made of stainless steel such as SUS347.

  The outer diameter d3 of the insertion pin 30 is slightly larger than the inner diameter d4 of the long hole 14 of the bolt 10 at room temperature (for example, in the temperature range of 0 to 40 ° C.) as shown in FIG. At times (for example, −10 to −50 ° C.), the size becomes equal to or less than the inner diameter d4 of the long hole 14 due to thermal contraction.

  FIG. 6 shows a method of fastening the fastener 100 according to the present invention having such a configuration. First, as shown in FIG. 2A, the insertion pin 30 before insertion is cooled and the whole is cooled to about −40 ° C. all at once. As a method of cooling the insertion pin 30, a method of directly spraying a spray-type instantaneous coolant as in the above-described embodiment and cooling the whole may be used. If the dedicated cooling box 40 as shown in FIG. 5 is used, the coolant can be efficiently cooled without wasting the coolant.

  The cooling box 40 has a plurality of insertion holes 42 formed on the upper surface of a cubic housing 41 and a coolant injection hole 43 formed on the side surface thereof. Then, as shown in the figure, the spray type instantaneous coolant as in the above-described embodiment is supplied from the coolant injection hole 43 while the insertion pins 30 are inserted into the insertion holes 42 and held so as to be hung. If it is injected into the inside for several seconds to several tens of seconds, the plurality of insertion pins 30 held in each insertion hole 42 can be cooled to about -40 ° C. at a stretch safely and efficiently.

  When the insertion pin 30 is cooled to about −40 ° C. in this way, it has been confirmed that the diameter d3 is about 10% smaller than that at normal temperature (for example, 20 ° C.) due to thermal contraction. Then, while maintaining this cooling state, the taper is inserted into the elongated hole 14 of the bolt 10 from the tapered tip 31 as shown in FIG. In this operation, since the diameter d3 of the insertion pin 30 is reduced, the insertion can be smoothly performed. However, if not, the head 32 may be struck by a hammer or the like for press-fitting.

  Thereafter, if left in that state, as shown in FIG. 3C, the insertion pin 30 is thermally expanded as the temperature of the insertion pin 30 rises to the normal temperature range, and the outer diameter d3 also returns to the original size. As described above, since the outer diameter d3 of the insertion pin 30 in the normal temperature region is slightly larger than the diameter d4 of the elongated hole 14 of the bolt 10, it strongly adheres to the surface of the elongated hole 14 of the bolt 10 as the temperature rises. The diameter is increased so that the long holes 14 will be expanded.

  Then, similarly to the first embodiment, the threaded portion 12 of the bolt 10 expands so as to gradually bite into the surface of the thread groove of the nut 20, and eventually comes into close contact with the nut 20 so as to expand the thread groove of the nut 20. As a result, the bolt 10 and the nut 20 are firmly screwed together, so that the nut 20 is not easily loosened even if vibration is applied to the bolt 10.

  When the bolt 10 is removed from this state, if the spray type instantaneous coolant is sprayed on the head 31 of the insertion pin 30 or the entire bolt 10, the insertion pin 30 or the entire bolt 10 is thermally contracted and its threaded portion. Since the outer diameter d1 of 12 becomes small, the nut 20 can be easily removed. Moreover, since the fastener 100 of the present embodiment is also simple in structure, the manufacturing cost is low. In addition, the long hole 14 formed in the bolt 10 may not be penetrated, or the screw portion 12 may be perforated from the tip side and the insertion pin 30 may be inserted from the tip side. Further, the insertion pin 30 is not limited to stainless steel as described above, and may be carbon steel, titanium, aluminum, or other metals or resins.

[Third Embodiment]
Next, FIGS. 8 and 9 show a third embodiment of the fastener 100 according to the present invention. As shown in the figure, the fastener 100 includes a bolt 10, a nut 20 that is screwed to the bolt, and a press-fit pin 50. A slit (cut) S is formed in the screw portion 12 of the bolt 10, and the press-fit pin 50 is press-fitted into the slit S. This slit S is formed over substantially the whole from the tip side of the screw portion 12, and the screw portion 12 can be divided in the vertical direction from the tip side.

  On the other hand, the entire press-fit pin 50 has a diameter that is slightly tapered toward the distal end side, and a flat portion 51 for driving is integrally formed at the top, and the overall shape is substantially the same. It has a thumbtack shape. The press-fit pin 50 is also made of a material having high strength such as carbon steel or stainless steel.

  FIG. 9 shows a fastening method of the fastener 100 according to the present invention having such a configuration. First, as shown in FIGS. 4A and 4B, a nut 20 is screwed into the threaded portion 12 of the bolt 10 in the same manner as a normal bolt. At this time, as shown in FIG. 4B, when the nut 20 is screwed to a specified position, the screw portion 12 has the screw portion 12 so that the tip of the screw portion 12 protrudes from the nut 20 by a predetermined length, for example, about 10 to 20 mm. The bolt 10 is selected.

  When the nut 20 is screwed to the specified position, the press-fit pin 50 is press-fitted into the slit S from the tip end side of the screw portion 12 protruding from the nut 20 as shown in FIG. Since this bolt 10 is usually made of a high hardness material such as carbon steel or stainless steel, it is difficult to press-fit with bare hands. For example, the press-fit pin 50 is lightly inserted into the tip of the slit S with a finger and held. Striking it with a hammer in the condition.

  Then, as shown in FIG. 6C, the press-fit pin 50 is press-fitted into the slit S at the tip of the screw portion 12, and at the same time, the slit S is separated into the left and right so as to expand radially outward. As a result, as in the above-described embodiment, the screw portion 12 is firmly in contact with the nut 20 so as to spread the nut 20, so that the nut 20 is not loosened even if vibration is applied to the bolt 10. Further, in the present embodiment, after the fastening, the outer diameter of the screw portion 12 becomes larger as it goes to the tip end side, so that even if the nut 20 is loosened, it will fall off from the tip end of the screw portion 12 as it is. There is nothing wrong. Further, since the structure is simple in this embodiment, the manufacturing cost is also low.

  If a small hole H or a tapered groove M connected to the slit S is further formed at the tip of the screw portion 12, and the press-fit pin 50 is press-fitted using the small hole H or the groove M as a guide, it is more reliable and easy. The diameter-expanding work of the screw part 12 can be performed. Further, the slit S may be plural, and may have a structure in which the threaded portion 12 can be divided into three or more.

DESCRIPTION OF SYMBOLS 100 ... Fastener 10 ... Bolt 11 ... Head 12 ... Screw part 13, 14 ... Long hole 20 ... Nut 30 ... Insertion pin 40 ... Cooling box 41 ... Housing 42 ... Insertion hole 43 ... Injection hole 50 ... Press-fit pin S …slit

Claims (3)

It consists of a bolt, a nut, and an insertion pin, and has a long hole for inserting the insertion pin in the shaft portion of the screw portion of the bolt, and the diameter of the insertion pin is larger than the diameter of the long hole in a normal temperature range , And the fastener characterized by being equivalent to the diameter of the said long hole or smaller than that by the heat shrink in the low temperature range below -10 degreeC. The fastener according to claim 1 ,
The fastener is characterized in that the insertion pin is made of any one of SUS301, SUS304, SUS304L, SUS309S, SUS310S, SUS316, SUS316L, SUS317, SUS321, and SUS347. A fastening method using the fastener according to claim 1 or 2 ,
The insertion pin is cooled to a temperature whose diameter is equal to or smaller than the diameter of the elongated hole, and after inserting a nut into the bolt, the insertion pin is press-fitted into the elongated hole of the bolt. The fastening method characterized by the above-mentioned.

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