Patent Publication Number: US-2020300287-A1

Title: Caulking bolt

Description:
TECHNICAL FIELD 
     The present invention relates to a caulking bolt. 
     BACKGROUND ART 
     As described in Patent Literature 1, a caulking bolt that is crimp-fixed to a plate-like crimped member is known. The caulking bolt described in Patent Literature 1 has a groove which is formed in the outer circumference of the shank so that removal force is secured. In addition, a protrusion for whirl-stop is provided on the bearing face so as to extend in the longitudinal direction of the shank. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: JP 2017-155860 A 
       
    
     Meanwhile, in the configuration described in Patent Literature 1, machining is required for both the shank and the bearing face. Also, with the configuration described in Patent Literature 1, the distance between the bearing face and the regular thread start is long. With such a caulking bolt, if the thickness of the crimped member is thin, there is a possibility that the caulking bolt cannot be fastened to the nut. In addition, when a member made of a soft material such as aluminum is used for the crimped member, even if an attempt is made to perform the whirl-stop by the protrusion provided around the shank of the bearing face, it is not possible to exhibit a sufficient function. 
     SUMMARY OF INVENTION 
     Technical Problem 
     The inventors of the present invention have solved this problem by intensively studying this point. An object of the present invention is to make it possible to use the bearing face for securing whirl-stop and removal force. 
     Solution to Problem 
     In order to solve the above problem, according to the present invention, there is provided a caulking bolt including a shank and a head, wherein a bearing face of the head has, along an outer circumference of the shank, a groove having a ring shape into which a crimped member is fitted, and wherein the caulking bolt includes a projection and a depression for whirl-stop in the groove. 
     In addition, it is preferable that the groove be configured such that a deep portion spreads more outward than a shallow portion. 
     It is preferable that the angle formed by the outer peripheral face of the groove and the outer peripheral reference face of the head be 10 degrees or more and 20 degrees or less, and the groove have a plurality of projections and depressions. 
     Further, it is preferable that the depth of the groove be 0.9 mm or more and 1.3 mm or less. 
     Further, it is preferable that the crimped member be plastically deformed and allowed to flow into a regular thread start of the shank. 
     It is also preferable that the shank have a regular thread start at a position where a shortest distance between the regular thread start and the bearing face is 1.2 mm or less. 
     Further, it is also preferable that a crimping structure in which an aluminum crimped member is crimped into the caulking bolt be provided. 
     It is also preferable that a crimping structure in which a regular thread start provided on the caulking bolt is positioned in a hole of a crimped member be provided. 
     Advantageous Effects of Invention 
     In the present invention, the bearing face can be used for securing whirl-stop and removal force. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view of a caulking bolt according to an embodiment. 
         FIG. 2  is a view of a caulking bolt according to the embodiment as viewed from the tip of a shank. 
         FIG. 3  is a cross-sectional view taken along the line in  FIG. 2 . 
         FIG. 4  is a partial enlarged view of the IV region of  FIG. 3 . 
         FIG. 5  is a partial enlarged view of the V region of  FIG. 2 . 
         FIG. 6  is a side view showing a state in which a caulking bolt according to the embodiment and a crimped member are crimped. However, it partially shows a cross section. 
         FIG. 7  is a side view of a caulking bolt according to another embodiment. 
         FIG. 8  is a cross-sectional view showing a state where the caulking bolt shown in  FIG. 7  and a crimped member are crimped as viewed from the side. 
         FIG. 9  is a view of a caulking bolt of a modification in which the outer shape of the head is changed as viewed from the tip of the shank. 
         FIG. 10  is a view of a caulking bolt of a modification in which a protrusion having a whirl-stop function is provided in a groove as viewed from the tip of the shank. 
         FIG. 11  is a view of a caulking bolt of a modification in which projections having a whirl-stop function are provided on an inner peripheral face of a groove as viewed from a tip end side of a shank. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, modes for carrying out the invention will be described. In the following description, a caulking bolt  1  will be described by taking an iron M6 bolt as an example. As can be understood from  FIGS. 1 to 3 , the caulking bolt  1  of the embodiment includes a shank  2  and a head  3 . A bearing face  31  of the head  3  has a groove  32  into which a crimped member  5  is fitted. The bearing face  31  of the head  3  has, along the outer circumference of the shank  2 , the groove  32  having a ring shape into which the crimped member  5  is fitted. Therefore, the crimped member  5  can be plastically deformed so as to be fitted into the groove  32 . This makes it easier to secure removal force. In addition, the groove  32  has projections and depressions for whirl-stop. Therefore, the bearing face  31  can be used for securing whirl-stop and removal force. In the embodiment, a crimping structure  10  is formed by crimping the crimped member  5  made of aluminum, which is relatively soft, into the caulking bolt  1 . The caulking bolt  1  having such a configuration can secure crimping strength with the crimped member  5 . 
     As can be understood from  FIGS. 2 and 3 , on the bearing face  31  of the caulking bolt  1  of the embodiment, the groove having a ring shape  32  is provided around the shank  2 . The groove  32  is a portion into which part of the plastically deformed crimped member  5  flows when the crimped member  5  is crimped into the caulking bolt  1 . The depth L 2  of the groove  32  is preferably 0.9 mm or more and 1.3 mm or less. It is more preferable that it be 1.0 mm or more and 1.1 mm or less. 
     Further, as shown in  FIG. 4 , in this example, the groove  32  is configured such that a deep portion spreads more outward than a shallow portion. Since the groove  32  is formed so that the outer diameter at the deep portion is larger than that at the shallow portion, the crimped member  5  plastically deformed so as to fit in the groove  32  and the caulking bolt  1  are easily maintained in a coupled state. In this case, from the viewpoint of crimping strength and formability, it is preferable that the angle θ formed by an outer peripheral face  33  of the groove  32  and an outer peripheral reference face  34  of the head  3  be 10 degrees or more and 20 degrees or less. If this angle θ is less than 10 degrees, there is a possibility that removal force shortage may occur, and if it exceeds 20 degrees, the non-defective rate decreases due to manufacturing difficulty. The outer peripheral reference face  34  is a portion positioned on the outer circumference of the head  3  and extends in the longitudinal direction of the shank  2 . 
     In addition, it is preferable that a plurality of projections  35  be provided in the groove  32  as projections and depressions for whirl-stop. With such a configuration, it is possible to perform whirl-stop of the caulking bolt  1 . The projections  35  of the embodiment are provided on the outer peripheral face  33  of the groove  32 . Therefore, it is possible to apply a force of whirl-stop to the caulking bolt  1  from the outer circumference of the crimped member  5  which has flowed into the groove  32 . As can be understood from  FIG. 5 , the projections  35  of the embodiment each are formed in a triangular shape in a plan view and are arranged at equal intervals on the outer peripheral face  33  of the groove  32 . 
     Since the screw thread  21  is provided on the shank  2  from the position where the shortest distance L 1  from the bearing face  31  is 1.2 mm or less toward the tip, the distance L 1  between the screw thread  21  and the bearing face  31  is shortened. Therefore, as shown in  FIG. 6 , the crimping structure  10  is configured such that a regular thread start  24  with which the caulking bolt  1  is provided is positioned in a hole  51  of the crimped member  5 . With such a structure, the screw thread  21  is positioned from the inside of the hole  51  of the crimped member  5  to the tip of the shank  2 . Therefore, it is possible to appropriately screw the female screw member to the caulking bolt  1 . 
     It should be noted that the caulking bolt  1  of the embodiment does not have a circular groove provided on the shank in order to secure the removal force. Instead of this groove, the groove  32  functions so as to ensure removal force. In the prior art, when the crimped member  5  is strongly crimped, the crimped member  5  may be bent as a whole. However, with such a configuration, such bending can be avoided. In addition, as described above, since the groove  32  provided on the bearing face  31  has the function of ensuring the removal force and the function of whirl-stop, restriction of the thickness of the crimped member  5  can be suppressed, and the crimping strength between the groove  32  and the crimped member  5  can be secured. 
     As in the examples shown in  FIGS. 1 to 6 , there is no need for the deep portion to be configured to spread more outward than the shallow portion. As shown in  FIG. 7 , the outer peripheral face  33  of the groove  32  may extend so as to be substantially orthogonal to the bearing face  31 . In the example shown in  FIG. 7 , the outer peripheral face  33  of the groove  32  has projections and depressions for whirl-stop. Further, the incomplete thread portion is provided relatively short, and the distance between the screw thread  21  and the bearing face  31  is set to be relatively short. For this reason, as shown in  FIG. 8 , it is possible to ensure removal force by plastically deforming the crimped member  5  so as to be in contact with the root of the shank  2 . In the example shown in  FIG. 8 , the crimping structure  10  is configured in which the regular thread start  24  provided on the caulking bolt  1  is positioned in the hole of the crimped member  5 . Further, the crimped member  5  can be plastically deformed and allowed to flow into the regular thread start  24  of the shank  2 . 
     In the above-described embodiment, the outer shape of the head  3  is circular when viewed from the tip of the shank  2 , but as an example shown in  FIG. 9 , the outer shape of the head  3  may be quadrangular. Also in the example shown in  FIG. 9 , the groove  32  provided on the bearing face  31  of the head  3  is configured such that the deep portion spreads more outward than the shallow portion. A plurality of projections  35  are provided on the outer peripheral face of the groove  32 . However, as shown in  FIG. 7 , the outer peripheral face  33  of the groove  32  may extend so as to be substantially orthogonal to the bearing face  31 . 
     Instead of the projections  35 , the whirl-stop function may be performed by a protrusion  37  extending from the bottom face of the groove  32  toward the hearing face  31 . In an example shown in  FIG. 10 , a plurality of protrusions  37  extending from the inner peripheral face to the outer peripheral face are radially arranged in the groove  32 . Also in the example shown in  FIG. 10 , the groove  32  provided on the bearing face  31  of the head  3  is configured such that the deep portion spreads more outward than the shallow portion. However, as shown in  FIG. 7 , the outer peripheral face  33  of the groove  32  may extend so as to be substantially orthogonal to the bearing face  31 . 
     Further, as shown in  FIG. 11 , the projections  35  may be provided on the inner peripheral face of the groove  32  so that the whirl-stop function can be performed. Even in the example shown in  FIG. 11 , the groove  32  provided on the bearing face  31  of the head  3  is configured such that the deep portion spreads more outward than the shallow portion. However, as shown in  FIG. 7 , the outer peripheral face  33  of the groove  32  may extend so as to be substantially orthogonal to the bearing face  31 . 
     Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modes can be implemented. For example, the material of the caulking bolt need not be iron, and other materials may be used. In addition, the material of the crimped member need not be aluminum, and other materials may be used. Further, plating treatment may be applied. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1  caulking bolt 
               2  shank 
               3  head 
               5  crimped member 
               10  crimping structure 
               21  screw thread 
               24  regular thread start 
               31  bearing face 
               32  groove 
               33  outer peripheral face of the groove 
               34  outer peripheral reference face of head 
               35  projection 
               51  hole