JP3706561B2 - Bolt caulking structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a caulking structure of a bolt, particularly a bolt that needs to prevent a bolt head from dropping when it is broken.
[0002]
[Prior art]
When the bolt after it is broken for some reason, it usually breaks at the lower part of the neck of the bolt, but if the broken bolt head falls, there is a risk of causing trouble in the operation of the device that was fastened There is. For example, the baffle former bolt 03 of the nuclear reactor shown in FIG. 6 is an example, and FIG. 6 is a cross-sectional explanatory view of a main part of a baffle former bolt fastening portion between a former portion and a baffle plate in a conventional nuclear reactor. .
[0003]
The baffle former bolt 03 that fastens the former part 1 and the baffle plate 2 in the nuclear reactor is not subject to frequent maintenance in the reactor even if the neck of the bolt breaks due to severe usage conditions. In addition, it is necessary to be able to operate continuously for a certain period of time without any trouble, so it is necessary to prevent the bolt head 04 from falling into the furnace.
[0004]
Conventionally, as shown in FIG. 6, a bolt head 04 is welded and fixed to a bolt counterbore hole 05 with a washer-like stopper 06, and even if the bottom of the bolt is broken, etc. 04 stayed in that position.
[0005]
In FIG. 6, the baffle former bolt 03 is shown as a hexagon socket head bolt, but the same applies to a normal hexagon head bolt.
[0006]
[Problems to be solved by the invention]
However, in the fixing structure of the baffle former bolt 03 described above, it is difficult to replace and remove the bolt because of welding, and the fixing work at the time of fastening the bolt is complicated and the working conditions are restricted.
[0007]
The present invention can prevent the bolt head from falling even if the bolt breaks after fastening, can ensure the soundness of the structure to which the bolt is fastened, and hinders the operation of the equipment and plant in which the bolt is used. It is an object of the present invention to provide a bolt caulking structure that can prevent the occurrence of the occurrence of the trouble, and can easily replace, fasten, and fix the bolt, and also facilitate the remote work of the fastening work when the bolt is fastened.
[0008]
[Means for Solving the Problems]
  (1) The present invention has been made to solve such a problem, and as its first means, a flange portion projecting from the lower portion of the bolt head, and an outer periphery provided on the outer periphery of the flange portion. A flare portion that forms an annular wall, and a counterbore hole that is provided at an upper portion of the bolt hole and has an inner diameter that is slightly larger than the outer diameter of the flange portion and into which the bolt head including the flare portion and the flange portion is immersed. A plurality of caulking grooves provided at intervals in the circumferential direction of the side wall of the counterbore hole on the side of the flare portion, and formed by caulking the flare portion in a state where the bolt is fastened. The caulking protrusion is fitted into the caulking groove, and the height of the flare portion is set so that the flare top protrudes above the caulking groove at the position where the caulking protrusion is generated in the fitted state. Surface of the projection is pressed against the upper edge of the caulking grooveThe counterbore has an arc cross section or an inclined cross section in a direction in which the side wall closes the counterbore upward.A bolt caulking structure is provided.
[0009]
  According to the first means, it is possible to easily replace and fix the bolt for fixing by caulking without using welding, and in addition, the height of the flare portion is set so that the flare top part protrudes above the caulking groove. As the caulking projection is set, the convex surface is elastically pressed against the upper edge of the caulking groove, and when the bolt breaks, the bolt head does not move and the fall is prevented. Rotation and vibration of the part are also prevented.In addition, since the upper edge of the caulking groove provided on the side wall of the counterbore has a cross-section that slightly protrudes into the counterbore hole, the restraint on the bolt caulking protrusion from being pulled upward from the caulking groove is strengthened. The
[0010]
(2) As a second means, in the bolt caulking structure of the first means, the flare portion is vertically arranged in the axial direction of the bolt on both sides of the portion where the caulking protrusion is formed before the caulking process. A bolt caulking structure characterized by being provided with a slit is provided.
[0011]
According to the second means, in addition to the action of the first means, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated.
[0012]
(3) Further, as a third means, in the bolt caulking structure of the first means, the flare portion is laterally arranged in the circumferential direction of the bolt below a portion where the caulking protrusion is formed before the caulking process. A bolt caulking structure characterized by being provided with a slit is provided.
[0013]
According to the third means, in addition to the action of the first means, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated.
[0016]
  (4No.4As a means of the first handSteppedIn the bolt caulking structure, the bolt provides a bolt caulking structure characterized in that the flare portion forms an arc cross section or an inclined cross section in a direction in which the annular wall opens upward.
[0017]
  First4According to the means of the first handSteppedIn addition to the action, the flared portion of the bolt has a cross-section in which the upper edge slightly protrudes to the outside of the bolt, so that restraining the caulking protrusion from coming out of the caulking groove is strengthened.
[0018]
  (5) Furthermore5As a means, a flange portion projecting from the lower portion of the bolt head, a flare portion formed on the outer periphery of the flange portion and forming an annular wall extending upward, and a bolt is inserted and mounted below the bolt head A washer, a bolt hole provided at an upper portion of the bolt hole and having an inner diameter slightly larger than an outer diameter of the flange portion, the bolt head including the flare portion and the flange portion, and a counterbore hole for immersing the washer, A plurality of caulking grooves provided at intervals in the circumferential direction of the side wall of the same counterbore hole on the side of the flare portion, and formed by caulking the flare portion in a state where the bolt is fastened. The caulking protrusion is fitted into the caulking groove, and the height of the flare portion is set so that the flare top is located inside and below the upper edge of the caulking groove at the position where the caulking protrusion is generated in the fitted state. Is, a state where elastic compression distance of the washer in a state in which the bolt is fastened is fitted aboveInThe bolt caulking structure is characterized in that it is set to be larger than a gap distance formed between the top of the flare and the upper edge of the caulking groove.
[0019]
  First5According to the above means, the bolts can be easily replaced and fixed for caulking without using welding, and the top of the flare is located below the upper edge of the caulking groove and completely enters the caulking groove. Because the flare height is set in this way, the upper edge of the caulking protrusion engages with the upper edge of the caulking groove, and the elastic reaction force of the washer lifts the bolt head when the bolt breaks. Since the flared top of the caulking projection is pressed against and fixed to the upper edge of the caulking groove, the bolt head can be prevented from falling down, and the bolt head can be prevented from rotating and vibrating.
[0020]
  (6) Also,6As a means of5In the bolt caulking structure of the above means, the flare portion is formed by adding longitudinal slits in the axial direction of the bolt on both sides of the portion where the caulking projection is formed before the caulking process. Provides a caulking structure for bolts.
[0021]
  First6According to the means5In addition to the action of the means, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated.
[0022]
  (7No.7As a means of5In the bolt caulking structure of the above-mentioned means, the flare portion is obtained by adding a lateral slit in the circumferential direction of the bolt below a portion where the caulking protrusion is formed before the caulking process. Provides a caulking structure.
[0023]
  First7According to the means5In addition to the action of the means, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
  A bolt caulking structure according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional explanatory view of a main part of a baffle former bolt fastening portion between a former portion and a baffle plate in a nuclear reactor, and FIG. 2 is a view taken along the line AA in FIG. 3A and 3B are perspective views of modifications of the flare portion of the baffle former bolt according to the present embodiment, respectively, and FIGS. 4A and 4B are seats of the baffle plate according to the present embodiment. On the side wall of the holepreferableFIG. 4C and FIG. 4D are sectional views of modified examples of the flare portion of the baffle former bolt according to the present embodiment.
[0025]
In FIG. 1, 3 is a baffle former bolt, the bolt head 4 has a hexagonal portion, and a flange portion 8 projecting sideways is integrally formed below the head portion 4. Has a flare portion 6 having a thin wall (for example, about 0.5 mm thick) and a substantially vertical annular wall formed at a certain height upward.
[0026]
The bolt head 4 is inserted into a counterbore 5 provided in the upper part of the bolt hole 7 of the baffle plate 2 together with the flange portion 8, and the male screw portion of the baffle former bolt 3 (not shown) is screwed with the female screw portion of the former portion. It is concluded.
[0027]
The side wall 5a of the counterbore 5 has an inner diameter slightly larger than the outer diameters of the flare portion 6 and the flange portion 8, and the side wall 5a located on the side of the flare portion 6 of the fastened baffle former bolt 3 has Four caulking grooves 5b are provided on the entire circumference.
[0028]
In a state after the baffle former bolt 3 is fastened, the tip of the caulking tool 10 is inserted between the bolt head 4 and the flare portion 6, and the caulking tool 10 is in a position facing the caulking groove 5b. 3. A caulking process is performed by applying a caulking force F to the flare portion 6 from the central axis X 3 toward the outer periphery, and caulking projections 6a are formed on the flare portion 6 to be pushed out into the caulking groove 5b.
[0029]
On the other hand, the flare portion 6 is provided at a height where the flare top portion 6t is slightly protruded from the upper edge of the caulking groove 5b at the portion where the caulking protrusion 6a is formed, and the caulking protrusion 6a is formed in the caulking groove 5b. It is deformed into a convex shape in a state of being hooked on the peripheral edge and is fitted into the caulking groove 5b.
[0030]
In addition, although the example which provided the four crimping grooves 5b was shown, you may provide several appropriate places at intervals. Further, although the caulking operation is shown in FIG. 1 at one location, the caulking operation may be performed simultaneously at both locations on the opposite side of the central axis X, and at the same time all locations are performed simultaneously. There may be.
[0031]
In the present embodiment as described above, the bolts can be easily replaced and fixed for fixing by caulking tools without using welding as in the conventional bolt fixing structure shown in FIG. The bolt caulking structure has the following characteristics.
[0032]
When the baffle former bolt 3 is fastened, the flare portion 6 and the flange portion 8 have an outer diameter smaller than the inner diameter of the side wall 5a of the counterbore hole 5, so that the baffle former bolt 3 is screwed for fastening in the side wall 5a. The flare portion 6 is in a state adjacent to the caulking groove 5b of the counterbore hole 5 at the stage where it passes through and is fastened.
[0033]
After that, the caulking force F is applied to the flare portion 6 with the caulking tool 10 to perform caulking, and as shown in FIGS. 1 and 2, the caulking projection 6a is generated and the caulking groove 5b is caulked. The fitting of the projection 6a and the caulking groove 5b prevents the bolt head 4 from coming off and has a function of preventing the bolt head 4 from rotating.
[0034]
That is, the height of the flare portion 6 is set so that the flare top portion 6t leaves the protrusion a above the caulking groove 5b at the place where the caulking projection 6a occurs, and therefore, the caulking projection 6a has its convex surface. The caulking groove 5b is elastically pressed against the upper edge, and the movement is elastically restricted.
[0035]
Accordingly, if the baffle former bolt 3 is broken at the neck lower portion 3a or the like and loses the fastening force, the caulking protrusion 6a of the flare portion 6 is elastically restrained by the caulking groove 5b. The part 4 does not move and is prevented from dropping, and the rotation and vibration of the bolt head 4 are also prevented by elastic restraint, and damage that may occur over time due to vibration is also prevented.
[0036]
For this reason, even after the baffle former bolt 3 is broken, the bolt head 4 is prevented from vibrating and stops at that position, so that the soundness in the reactor can be secured and the operation of the reactor can be continued without any trouble.
[0037]
A modification of the present embodiment will be described with reference to FIG. The flared portion 6 of the modified example of FIG. 3A is applied in advance in the longitudinal direction (center axis X of the baffle former bolt 3) before crimping on both sides of the portion where the caulking force 6 is formed by applying the caulking force F. Direction) vertical slit 6b.
[0038]
According to this modification, the rigidity of the flare portion 6 can be reduced, and the caulking force F when the caulking tool 6 is processed by the caulking tool 10 can be reduced.
[0039]
Therefore, the caulking process by remote operation with the caulking tool 10 mounted on a robot or the like having a large caulking force F is also facilitated. In addition, the vertical slit 6b can be easily constructed and can be applied in a wide range.
[0040]
The flared portion 6 of the modified example of FIG. 3B is applied in advance in the lateral direction (around the central axis X of the baffle former bolt 3) before the caulking process below the portion where the caulking force F is applied and the caulking projection 6a is formed. The circumferential slit 6c is added.
[0041]
According to this modification, the rigidity of the flare portion 6 can be reduced, and the caulking force F when the caulking tool 6 is processed by the caulking tool 10 can be reduced.
[0042]
Therefore, the caulking process by remote operation with the caulking tool 10 mounted on a robot or the like having a large caulking force F is also facilitated. Further, the horizontal slit 6c can be easily provided and can be applied in a wide range.
[0043]
  Of this embodimentPreferred examples andStill another modification will be described with reference to FIG. FIG. 4 (a)ExampleThe counterbore 5 'of the baffle plate 2 has an arc cross section with an appropriate radius r1 in a direction in which the side wall 5a' closes the counterbore 5 'upward.
[0044]
  FIG. 4 (b)ExampleThe counterbore 5 ″ of the baffle plate 2 has an inclined cross section with an appropriate inclination angle θ1 in a direction in which the side wall 5a ″ closes the counterbore 5 ″ upward.
[0045]
Further, the baffle former bolt 3 ′ of the modified example of FIG. 4 (c) has an arc cross section with an appropriate radius r2 so that the flare portion 6 ′ warps outward in the direction of opening the annular wall upward. It is what forms.
[0046]
The baffle former bolt 3 ″ of the modification of FIG. 4 (d) has an inclined cross section with an appropriate inclination angle θ2 in which the flare portion 6 ″ is inclined in a direction to open the annular wall upward. It is.
[0047]
  These in FIG.Preferred examples andWhen the modified example is used, that is, in the case of the counterbore 5 ′, 5 ″ of (a) or (b), the upper edge of the caulking groove 5b ′ or 5b ″ provided therein is the inside of the counterbore Since it has a slightly protruding cross section, the restraint against the caulking protrusion 6a of the flare portion 6 of the baffle former bolt 3 from being pulled upward is strengthened, and the intended effect of preventing the bolt head 4 from falling when it breaks. Can be made more reliable.
[0048]
In the case of the baffle former bolts 3 'and 3 "in (c) or (d), the flare portions 6' and 6" have a cross section in which the upper edge slightly protrudes to the outside of the bolt, so that the upper edge of the caulking groove 5b It is possible to reinforce the engagement of the caulking projection 6a to the upper side and strengthen the restraint against the upward movement from the caulking groove 5b, thereby further ensuring the expected effect of preventing the bolt head 4 from falling when it breaks. it can.
[0049]
And the counterbore 5 ', 5 "of FIG. 4 (a) or (b) and the flare portions 6', 6" of FIG. It is possible to enhance the prevention of falling when the portion 4 is broken.
[0050]
In any one of the above-described FIGS. 4A to 4D or a combination thereof, the flare portion 6, 6 ′ or 6 ″ is larger than the inner diameter of the upper edge portion of the counterbore 5, 5 ′ or 5 ″. The outer diameter of the edge (flare top 6t) may be slightly larger, but if the outer diameter of the flange 8 is set smaller than the inner diameter of the upper edge of the counterbore 5, 5 'or 5 " Since the flare portion 6, 6 'or 6 "is formed to be relatively thin and elastic, the flare portion 6, 6' or 6" is moved as the baffle former bolt 3, 3 'or 3 "is screwed for fastening. By being elastically deformed, it can enter into the counterbore 5, 5 'or 5 ", and at the stage of fastening, the caulking operation can be performed in the same state as shown in FIG.
[0051]
A bolt caulking structure according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional explanatory view of the main part of the bolt part of the former part 1 and the baffle plate 2 in the nuclear reactor as in FIG. 1, and the same reference numerals are given to the same parts as in the first embodiment of FIG. A description thereof will be omitted, and different points in the present embodiment will be mainly described below.
[0052]
The left half surface of the central axis X of the baffle former bolt 3 in FIG. 5 is a normal fastening state, and the right half surface is an explanatory view showing when the baffle former bolt 3 is broken.
[0053]
In the left half surface of FIG. 5, the baffle former bolt 3 has a bolt head portion 4 forming a hexagonal portion, and a flange portion 8 projecting laterally under the bolt head portion 4. A flare portion 61 having a thin wall (for example, about 0.5 mm thick) and forming a substantially vertical annular wall is formed at a certain height upward.
[0054]
The baffle former bolt 3 has a washer 11 mounted under the bolt head 4 around the neck lower portion 3 a, and the bolt head 4 together with the flange portion 8 and the flare portion 61 together with the bolt hole 7 of the baffle plate 2. The male screw portion of the baffle former bolt 3 (not shown) is screwed and fastened with the female screw portion of the former portion.
[0055]
The washer 11 is elastically deformed in the direction of the central axis X when the baffle former bolt 3 is tightened, and may be an ordinary spring washer or a material that is elastically compressed in the direction of the central axis X uniformly. Yes, bolts are generally selected according to their use conditions.
[0056]
The side wall 5a of the counterbore 5 has an inner diameter that is slightly larger than the outer diameters of the flare portion 61 and the flange portion 8, and is located on the side wall 5a located on the side of the flare portion 61 of the fastened baffle former bolt 3. Are provided with four caulking grooves 5b on the entire circumference.
[0057]
In a state after the baffle former bolt 3 is fastened, the tip of the caulking tool 10 is inserted between the bolt head 4 and the flare 61, and the caulking tool 10 is in a position facing the caulking groove 5b. 3. A caulking force F is applied to the flare portion 61 from the central axis X toward the outer peripheral direction to perform caulking, and a caulking projection 61a is formed on the flare portion 61 to be pushed out and fitted into the caulking groove 5b.
[0058]
On the other hand, the flare portion 61 has a flare apex 61t at the portion where the caulking projection 61a is formed, inside the upper edge of the caulking groove 5b (herein, "inner" means "in the caulking groove 5b") However, in the state after the insertion, the upper edge of the caulking protrusion 61a (flare top 61t) and the upper part of the caulking groove 5b are formed as shown in the figure. A certain amount of gap b is formed between the edges.
[0059]
Note that the elastic compression distance of the washer 11 in the state where the baffle former bolt 3 is fastened, that is, elastically return to the direction of the central axis X when the tightening force of the baffle former bolt 3 is removed. The distance is set to be greater than the gap b.
[0060]
Further, as in the first embodiment described above, the example in which the four caulking grooves 5b are provided has been described. However, an appropriate plurality of places may be provided in the circumferential direction at intervals. Further, although the caulking operation is shown in FIG. 5 at one location, the caulking operation may be performed simultaneously at both locations on the opposite side of the central axis X, and at the same time all locations are performed simultaneously. There may be.
[0061]
In the present embodiment as described above, the bolts can be easily replaced and fixed for fixing by caulking tools without using welding as in the conventional bolt fixing structure shown in FIG. The bolt caulking structure has the following characteristics.
[0062]
When the baffle former bolt 3 is fastened, the flare portion 61 and the flange portion 8 have an outer diameter smaller than the inner diameter of the side wall 5a of the counterbore hole 5, so that the baffle former bolt 3 is screwed for fastening in the side wall 5a. The flare portion 61 is in a state adjacent to the caulking groove 5b of the counterbore hole 5 at the stage where it passes through and is fastened.
[0063]
After that, when the caulking force F is applied to the flare portion 61 with the caulking tool 10 to form the caulking projection 61a as shown in FIG. 5 and the caulking groove 5b is fitted, the caulking projection 61a and the caulking groove 5b are fitted. In this case, the bolt head 4 can be prevented from coming off and the bolt head 4 can be prevented from rotating.
[0064]
That is, at the place where the caulking protrusion 61a is generated, the upper edge of the flare portion 61 (flare top portion 61t) is located inside and below the upper edge of the caulking groove 5b, and the flare portion 61 is completely inserted into the caulking groove 5b. Since the height is set, the upper edge of the caulking protrusion 61a engages with the upper edge of the caulking groove 5b, and the movement is restricted.
[0065]
Therefore, in the unlikely event that the baffle former bolt 3 breaks at the neck lower portion 3a as shown by the Y portion in the right half of FIG. 5 and loses the fastening force, the elastic reaction force of the washer 11 is as shown by the arrow R. The flared top 61t (upper edge) of the caulking projection 61a is pressed against and fixed to the step on the upper edge of the caulking groove 5b, and the bolt head 4 is reliably prevented from falling. Rotation and vibration of the bolt head 4 are also prevented, and damage that may occur over time due to vibration is also prevented.
[0066]
For this reason, even after the baffle former bolt 3 is broken, the bolt head 4 is prevented from vibrating and stops at that position, so that the soundness in the reactor can be secured and the operation of the reactor can be continued without any trouble.
[0067]
In the second embodiment, the modification in which the vertical slit 6b or the horizontal slit 6c of the flare portion 6 shown in FIG. 3 described in the first embodiment is provided can be similarly applied. In that case, the rigidity of the flare portion 61 can be reduced, the caulking force F when the caulking tool 61 is machined by the caulking tool 10 can be reduced, and the caulking process by remote operation by the caulking tool 10 mounted on a robot or the like becomes easy. The same can be done with a wide range of applications.
[0068]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications may be made to the specific structure within the scope of the present invention. .
[0069]
For example, although the said embodiment showed the thing of a hexagon head bolt as an example in the said embodiment, the kind of bolt heads, such as a hexagon socket head bolt, is not limited.
[0070]
In the above embodiment, the baffle former bolt that is extremely effective in carrying out the present invention has been described as an example. However, the present invention can be applied to general bolts that are desired to prevent the bolt head from dropping when the bolt breaks. It is.
[0071]
Further, in this specification (including claims), the expressions of “up”, “down”, “right”, and “left” are described with reference to the states shown in FIGS. In the description of the configuration, the relationship between the directions shown in the drawings is prescribed, but it does not mean that the bolt and the caulking structure of the bolt according to the present invention are used only in the direction shown in the drawings. For example, it includes a case where the central axis X of the baffle former bolt shown in the embodiment is horizontally arranged, arranged obliquely, or inverted and arranged.
[0072]
【The invention's effect】
  (1) According to the invention of claim 1, the bolt caulking structure has a flange portion projecting from the lower portion of the bolt head portion, and a flare that forms an annular wall provided on the outer periphery of the flange portion and extending upward. And a counterbore hole that is provided at an upper portion of the bolt hole and has an inner diameter slightly larger than an outer diameter of the flange portion and into which the bolt head including the flare portion and the flange portion is inserted, and a side of the flare portion A plurality of caulking grooves provided at intervals in the circumferential direction of the side wall of the counterbored hole, and the caulking protrusions formed by caulking the flare portion in a state where the bolts are fastened. The height of the flare portion is set so that the top of the flare protrudes above the caulking groove at the position where the caulking protrusion is generated in the fitted state, and the surface of the caulking protrusion is above and below the caulking groove. left It is pressed against the edgeThe counterbore has an arc cross section or an inclined cross section in a direction in which the side wall closes the counterbore upward.Therefore, the bolts can be easily replaced and fixed for caulking without using welding, and the height of the flare remains so that the top of the flare protrudes above the caulking groove. As the caulking projection is set, the convex surface is elastically pressed against the upper edge of the caulking groove, and when the bolt breaks, the bolt head does not move and the fall is prevented. Rotation and vibration of the part are also prevented, and damage that may occur over time due to vibration is also prevented.In addition, since the upper edge of the caulking groove provided on the side wall of the counterbore has a cross-section that slightly protrudes into the counterbore hole, the restraint on the bolt caulking protrusion from being pulled upward from the caulking groove is strengthened. Moreover, the fall prevention at the time of a fracture | rupture of a bolt head becomes more reliable.For this reason, even after the rupture of the bolt, the soundness of the structure to which the bolt is fastened can be secured, and the operation of the used apparatus and plant can be continued without any trouble.
[0073]
(2) According to the invention of claim 2, in the bolt caulking structure according to claim 1, the shaft of the bolt is formed on both sides of the portion where the flare portion forms the caulking projection before the caulking process. In addition to the effect of the first aspect of the invention, the flare portion can be reduced in rigidity and the caulking force can be reduced, so that the caulking process is facilitated and mounted on a robot or the like. The caulking process by remote operation with a caulking tool is also facilitated. Moreover, the vertical slit itself can be easily constructed and can be applied in a wide range.
[0074]
(3) According to the invention of claim 3, in the bolt caulking structure according to claim 1, the flare portion is provided in a circumferential direction of the bolt below a portion where the caulking protrusion is formed before the caulking process. In addition to the effect of the invention of claim 1, the flare portion can be reduced in rigidity and the caulking force can be reduced, so that the caulking process is facilitated and mounted on a robot or the like. The caulking process by remote operation with a caulking tool is also facilitated. Moreover, the installation which provides a horizontal slit itself is easy, and it can be made into a thing with a wide application range.
[0076]
  (4Claim4According to the invention of claim1In the bolt caulking structure described above, the bolt is configured such that the flare portion forms an arc cross section or an inclined cross section in a direction in which the annular wall opens upward.1'sIn addition to the effects of the invention, the flared portion of the bolt has a cross section with its upper edge slightly protruding outward from the bolt, so that the restraint of the caulking projection from coming out of the caulking groove is strengthened, and when the bolt head breaks Fall prevention is more reliableBecome.
[0077]
  (5This claim5According to the invention, the bolt caulking structure includes a flange portion projecting from the lower portion of the bolt head portion, a flare portion that is provided on the outer periphery of the flange portion and forms an annular wall extending upward, and the bolt is inserted. A washer mounted below the bolt head, and a bolt head and washer provided at an upper portion of the bolt hole and having an inner diameter slightly larger than an outer diameter of the flange portion, including the flare portion and the flange portion. A counterbore hole to be immersed and a plurality of caulking grooves provided at intervals in the circumferential direction of the side wall of the counterbore hole on the side of the flare part, and the bolt is fastened to the flare part The caulking protrusion formed by caulking is fitted into the caulking groove, and the flare top is located below the upper edge of the caulking groove at the position where the caulking protrusion is generated in the fitted state. State where the set height of the flared part is elastically compressed length of the washer in a state in which the bolt is fastened is fitted aboveInSince it is configured to be set larger than the gap distance that can be formed between the top of the flare and the upper edge of the caulking groove, the bolts can be easily replaced and fixed for caulking without using welding. Since the top of the flare is located inside and below the upper edge of the caulking groove and the height of the flare is set so as to completely enter the caulking groove, the upper edge of the caulking protrusion is within the upper edge of the caulking groove. When the bolt breaks when engaged, the elastic reaction force of the washer works so as to lift the bolt head, and the flared top of the crimping projection is pressed against the step on the upper edge of the crimping groove to fix it. In addition to reliably preventing the fall, rotation and vibration of the bolt head are also prevented, and damage that may occur over time due to vibration is also prevented. For this reason, even after the rupture of the bolt, the soundness of the structure to which the bolt is fastened can be secured, and the operation of the used apparatus and plant can be continued without any trouble.
[0078]
  (6Claim6According to the invention of claim5In the bolt caulking structure described above, the flare portion is configured such that longitudinal bolts in the axial direction of the bolt are added to both sides of the portion where the caulking protrusion is formed before the caulking process. , Claims5In addition to the effects of the invention, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated, and the caulking process by remote operation with caulking tools mounted on a robot or the like is facilitated. In addition, the vertical slit can be easily installed, and can be applied in a wide range.
[0079]
  (7Claim7According to the invention of claim5In the bolt caulking structure described above, since the flare portion is configured such that a lateral slit in the circumferential direction of the bolt is added below a portion where the caulking projection is formed before the caulking process. Claim5In addition to the effects of the invention, the rigidity of the flare portion can be reduced and the caulking force can be reduced, so that the caulking process is facilitated, and the caulking process by remote operation with caulking tools mounted on a robot or the like is facilitated. Moreover, the installation which provides a horizontal slit itself is easy, and it can be made into a thing with a wide application range.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a caulking structure of a bolt according to a first embodiment of the present invention, and is a cross-sectional view of a main part of a baffle former bolt fastening portion between a former portion and a baffle plate in a nuclear reactor.
FIG. 2 is a view taken along the line AA in FIG.
FIGS. 3A and 3B are perspective views of modifications of the flare portion of the baffle former bolt according to the first embodiment. FIG.
FIGS. 4A and 4B are views of the side wall of the counterbore of the baffle plate according to the first embodiment.preferableIt is sectional drawing of an example, (c), (d) is sectional drawing of the modification of the flare part of the baffle former volt | bolt of 1st Embodiment, respectively.
FIG. 5 is an explanatory view of a caulking structure of a bolt according to a second embodiment of the present invention, and is a cross-sectional view of a main part of a baffle former bolt fastening portion between a former portion and a baffle plate in a nuclear reactor.
FIG. 6 is an explanatory diagram of a conventional bolt caulking structure, and is a cross-sectional view of a main part of a baffle former bolt fastening portion between a former portion and a baffle plate in a nuclear reactor.
[Explanation of symbols]
1 Former
2 Baffle plate
3, 3 ', 3' baffle former bolt
3a lower neck
4 bolt head
5, 5 ', 5 "counterbore
5a, 5a ', 5a "sidewall
5b, 5b ', 5b "Caulking groove
6, 6 ', 6 "flare
6a Caulking projection
6b Vertical slit
6c Horizontal slit
6t flare top
7 Bolt hole
8 Flange
10 Caulking bracket
11 Washer
61 Flare
61a Caulking protrusion
61t Flare top

Claims (7)

A flange portion that protrudes below the bolt head, a flare portion that forms an annular wall provided on the outer periphery of the flange portion and extends upward, and is slightly larger than the outer diameter of the flange portion provided at the upper portion of the bolt hole A plurality of counterbore holes that have an inner diameter and that immerse the bolt head including the flare part and the flange part, and are provided at intervals in the circumferential direction of the side wall of the counterbore hole on the side of the flare part. A caulking groove that is formed by performing caulking on the flare portion in a state in which the bolt is fastened, and is fitted into the caulking groove. The height of the flare portion is set so that the top portion protrudes above the caulking groove, the surface of the caulking protrusion is pressed against the upper edge of the caulking groove, and the counterbore hole has the side wall that is Upward Only in the closing direction of the arcuate cross-sectional or caulking structure of the bolt, characterized in that the oblique section is formed comprising,.   2. The bolt caulking structure according to claim 1, wherein the flare portion is formed by adding longitudinal slits in the axial direction of the bolt on both sides of a portion where the caulking protrusion is formed before the caulking process. The caulking structure of the bolt that is characteristic. 2. The bolt caulking structure according to claim 1, wherein the flare portion is obtained by adding a lateral slit in the circumferential direction of the bolt below a portion where the caulking protrusion is formed before the caulking process. caulking structure of the bolt to be. 2. The bolt caulking structure according to claim 1 , wherein the bolt is formed by forming an arc cross section or an inclined cross section in a direction in which the flare portion opens the annular wall upward. Construction. A flange portion projecting from the lower portion of the bolt head, a flare portion formed on the outer periphery of the flange portion and forming an annular wall extending upward, and a washer inserted through the bolt and attached to the lower portion of the bolt head A bolt hole provided in an upper portion of the bolt hole and having an inner diameter slightly larger than an outer diameter of the flange portion, including the flare portion and the flange portion, and a counterbore hole for immersing the washer, and a side of the flare portion A plurality of caulking grooves provided at intervals in the circumferential direction of the side wall of the counterbore, and the caulking protrusion formed by caulking the flare portion in a state where the bolt is fastened. The height of the flare portion is set so that the flare top is positioned inside and below the upper edge of the caulking groove at the place where the caulking protrusion is generated in the fitted state. Bolts elastic compression distance of the washer in a state in which bets are fastened, characterized in that formed by larger than the gap distance can be between the upper edge of the flare top and caulking groove definitive state fitted above Caulking structure. 6. The bolt caulking structure according to claim 5 , wherein the flare portion is formed by adding longitudinal slits in the axial direction of the bolt on both sides of the portion where the caulking protrusion is formed before the caulking process. The caulking structure of the bolt that is characteristic. 6. The bolt caulking structure according to claim 5 , wherein the flare portion is obtained by adding a lateral slit in the circumferential direction of the bolt below a portion where the caulking projection is formed before the caulking process. The bolt caulking structure.

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