JP5500444B2 - Screw fastening method - Google Patents

Description

  The present invention relates to a screw fastening method for completing fastening with a predetermined axial force when fastening with bolts or nuts.

  In general, a torque method, a nut rotation angle method, and a torque gradient method (point resistance detection method) are employed as a screw fastening method for managing the screw tightening force. Then, as a final confirmation of whether or not the fastening has been completed after the introduction of a predetermined axial force, the torque coefficient value in the tightening of the bolt in the elastic region is OK with respect to the target set value by the torque wrench even though the torque coefficient value has a large variation. , NG determination is performed.

  However, as described above, in the screw tightening management method using the torque wrench, the determination is OK or NG with respect to the set target value. In the elastic region tightening, a visual check and numerical confirmation of whether or not the predetermined axial force is introduced and the tightening is completed. There was no means. In other words, the screw tightening operator does not have a method of confirming whether or not the tightening has been completed reliably by introducing the prescribed axial force, and relies on a torque wrench without confirming that there are no places to forget to tighten. Reality. For this reason, it seems that the fastening has been completed, but in reality, there has been a problem that there may be a shortage of axial force due to co-rotation and occurrence of slipping.

  As a method for confirming tightening of bolts other than the above, a pin tail portion is provided at the tip of the screw portion via a break groove like a torcia bolt, and when a predetermined torque is reached, a reaction force of the tightening torque is received at the pin tail portion. Bolts that allow visual confirmation and axial force confirmation by breaking the fracture groove part are known, but the use of the pin tail part through the fracture groove at the tip of the screw part is used. The location and application are limited to a narrow range, and most high-strength bolts are currently used without the pin tail.

  Therefore, the present invention can be surely and accurately performed with the axial force that is required for screw fastening by a combination of two specially shaped washers and control with an electric wrench. In addition, the tightening can be confirmed by visual confirmation. It is an object to provide a screw fastening method.

  In order to solve the above problem, the invention according to claim 1 of the present application is a screw fastening method that enables proper fastening without being affected by the torque coefficient, and is relative to the fastening seat surface of the bolt or nut with a head. A polygonal plain washer having a larger contour than the contour of the head or nut interposed in a rotatable manner, a plurality of convex portions on the front surface side, and a back surface interposed between the plain washer and the fastening member A washer with a convex part with a plurality of recesses corresponding to each convex part on the side, a rotating inner wrench that fits into the head or nut of a bolt with a head, and a fixed side that fits into a polygonal flat washer Using an electric wrench having an outer sleeve, the convex part of the washer with the convex part is completely crushed and depressed with an axial force that is required to be lower than the yield point of the bolt with the head or the bolt to which the nut is screwed. While set in each recess A fluid having visibility such as paint or resin is accommodated, and a relief groove extending radially outward from each recess and opened to the outer peripheral surface is provided. Engage the head or nut of the bolt with head and fit the outer sleeve into the flat washer, then drive the electric wrench to rotate the bolt or nut with head using the inner wrench, while the outer sleeve Tighten under the condition that the washer with the convex part is not affected by the rotational torque of the bolt or nut with the head, preventing the flat plain washer from rotating together, and then the shaft to be obtained lower than the above yield point When the force is reached, each convex part of the washer with the convex part is completely crushed and the depression is completed, and the fluid in each concave part oozes out to the outer peripheral part of the washer with the convex part through the escape groove. Electric wrench motor current change point due to the completion of the depression is electrically captured, and the electric wrench is stopped as the change point where the axial force to be obtained by the headed bolt or nut is introduced .

  According to the screw fastening method of the present invention, when the screw is fastened, the headed bolt or nut is rotated by the inner wrench while the outer sleeve of the electric wrench prevents co-rotation of the polygonal flat washer, and the convex portion is formed. When the head washer is tightened under the condition that it is not affected by the rotational torque of the headed bolt or nut, and the axial force that is lower than the yield point of the headed bolt or nut is reached, the washer with the convex portion Each convex part of the electric wrench is completely crushed and collapsed, and the fluid in each concave part oozes out to the outer periphery of the washer with the convex part through each escape groove, while at the same time The electric wrench is stopped as a changing point where an axial force to be obtained by a head-mounted bolt or nut is introduced by electrically detecting the changing point of the motor current. As a result, the axial force is applied to the washer with the convex portion without being affected by the torque coefficient, and the screw force can be reliably and accurately obtained with the axial force to be obtained, and in addition, the collapse of the convex portion of the washer with the convex portion is completed. By visually confirming the seepage of the fluid to the outer peripheral portion, it is possible to visually confirm whether the required axial force has been introduced and screw fastening has been completed. Therefore, two specially shaped washers are required and costly, but this is an effective screw fastening method for fastening important parts that require tightening confirmation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a bolt 1 with a head, a polygonal flat washer 2 and a washer 3 with a convex part used in the screw fastening method according to the present invention.

  As shown in FIG. 1, the head-attached bolt 1 includes a shaft portion 11 having a screw 11 a formed on the outer periphery, and a circular head portion 12 having a hexagonal hole 12 a at the center.

  The polygonal plain washer 2 has a hexagonal shape with a contour larger than the outer diameter of the head 12 of the head-mounted bolt 1 as shown in FIGS. 1 to 3, and the shaft of the head-mounted bolt 1 at the center thereof. A through hole 2a that allows insertion of the portion 11 is formed, and is interposed so as to be relatively rotatable with respect to the seating surface 12b of the head 12 of the head-mounted bolt 1.

  As shown in FIGS. 1, 4, and 5, the washer 3 with a convex portion is disk-shaped and has a through hole 3 a that allows insertion of the shaft 11 of the bolt 1 with a head at the center thereof. A plurality (three in the figure) of convex portions 3b... 3b are formed to bulge on the front surface side, and recesses 3c... 3c corresponding to the convex portions 3b. In that case, each of the convex portions 3b... 3b has a strength that completely collapses when the axial force to be obtained is lower than the axial force at the yield point A of the headed bolt 1 as shown in FIG. Is set. Specifically, the axial force at the time point B when the convex portions 3b... 3b are completed is set based on the formula of axial force at the yield point A × 0.5 to 0.8. Each recess 3c... 3c accommodates a fluid (hereinafter referred to as paint) 4 having a visibility such as paint or resin, and extends radially outward from each recess 3c. Are provided with relief grooves 3d. As shown in FIG. 7, the convex washer 3 is interposed between the polygonal flat washer 2 and a fastened member 7 described later.

  In FIG. 7, reference numeral 5 denotes a rotation-side inner wrench 51 that fits into the hexagonal hole 12 a of the head 12 of the head-mounted bolt 1, and a fixed-side outer that fits around the outer periphery of the polygonal flat washer 2. An electric wrench having a sleeve 52. The electric wrench 5 includes a motor 53, a motor shaft 54 to which the inner wrench 51 is detachably attached, a switch (not shown), and a controller 55. The controller 55 is provided with each convex portion of the washer 3 with a convex portion. The change point of the motor current of the motor 53 accompanying the completion of the depression of the parts 3b... 3b, that is, the change point of the axial force (motor current) -time at the completion of the depression of the convex part as is apparent from FIG. The motor 53 is turned off and the electric wrench 5 is automatically stopped as a changing point where the axial force to be obtained by the head-mounted bolt 1 is introduced.

  FIG. 7 shows a case where the fastened member 7 is screwed to the fastening member 6 using the head-mounted bolt 1, the polygonal flat washer 2, the convex washer 3, and the electric wrench 5. In the fastening member 6, a screw hole 6 a that is screwed with the screw 11 a of the head-mounted bolt 1 is formed, and the shaft member 11 of the head-mounted bolt 1 is inserted into the fastened member 7. An allowing insertion hole 7a is formed.

  Next, an effect | action at the time of fastening the to-be-fastened member 7 to the fastening member 6 using the screw fastening method which concerns on this invention is demonstrated.

  At the time of fastening, first, as shown in FIG. 7, the inner wrench 51 of the electric wrench 5 is fitted into the hexagonal hole 12 a in the head 12 of the headed bolt 1 and the outer sleeve 52 is fitted into the outer periphery of the polygonal flat washer 2. Next, the electric wrench 5 is driven and the head-mounted bolt 1 is rotated by the inner wrench 51, while the outer sleeve 52 prevents the polygonal flat washer 2 from rotating together and receives the reaction force generated in the electric wrench 5. . By utilizing the co-rotation preventing action of the polygonal flat washer 2, the convex washer 3 positioned between the polygonal flat washer 2 and the fastened member 7 is attached with a head so as not to be affected by rotational torque. Tighten with bolt 1. Thereafter, when the axial force to be obtained lower than the yield point A of the bolt 1 is reached by tightening by the rotation of the bolt 1 with the head, each convex portion 3b... 3b of the washer 3 with the convex portion is completely formed as shown in FIG. It collapses to complete the sinking. When the convex portions 3b... 3b are completely depressed, the paint 4 in the recesses 3c... 3c oozes out to the outer peripheral portion of the convex washer 3 through the escape grooves 3d. Then, the controller 5 turns off the motor 53 and automatically stops the electric wrench 5 as the change point where the axial force to be obtained by the head bolt 1 is introduced. As a result, an axial force is applied to the washer 3 with the convex portion without being affected by the torque coefficient, and the axial force to be secured to the fastening member 6 of the fastened member 7 by the bolt 1 with the head is surely and accurately obtained. Can be done. Further, by visually confirming that the protrusion 4b of the washer 3 with protrusions 3b has been crushed to the outer peripheral portion of the paint 4, the axial force to be obtained by the bolt 1 with the head is introduced and screw fastening is performed. Tightening confirmation as to whether or not completed can also be made by visual inspection. ,

  As described above, according to the screw fastening method of the present invention, when the bolt 1 with a head is screwed into the screw hole 6 a of the fastening member 6 and the fastened member 7 is fastened to the fastening member 6, a special shape is obtained. The combination of the two washers 2 and 3 and the control with the electric wrench 5 enables the screw fastening with the head bolt 1 to be reliably and accurately performed by the axial force to be obtained, and the axial force to be obtained is introduced. Tightening confirmation as to whether or not fastening has been completed can be easily and reliably performed by visual confirmation. Therefore, this is an effective screw fastening method for fastening important portions that require tightening confirmation.

  In the above-described embodiment, the headed bolt 1 has been described as having the hexagonal hole 12a in the columnar head 12, but the hexagonal headed bolt 1 without the hexagonal hole 12a may be used. In that case, as the inner wrench 51 of the electric wrench 5, a hexagonal spanner type whose tip is fitted to the hexagonal head may be used.

  In the above-described embodiment, the polygonal flat washer 2 having a hexagonal shape is used. However, the polygonal flat washer 2 is not limited to a hexagonal shape. For example, a polygonal shape such as a dodecagon as shown in FIG. Of course there may be.

  Furthermore, in the above-described embodiment, the case where the head-mounted bolt 1 is screwed into the screw hole 6a of the fastening member 6 and fastened is described, but the nut 8 is provided on the fastening member 6 as shown in FIG. In the case where the fastened member 7 is fastened to the fastening member 6 by screwing with the screw body 6b, the two plain washers of the polygonal flat washer 2 and the convex washer 3 as described above, Whether the screw fastening with the nut 8 can be reliably and accurately performed with the axial force to be obtained by the combination of the control with the electric wrench 5 and whether the axial force to be obtained is introduced and the fastening is completed. Tightening can be easily and reliably confirmed by visual confirmation. Here, since the entire structure in FIG. 10 is almost the same as that of the previous embodiment, the same reference numerals are given, and detailed description of the structure is omitted.

  That is, at the time of fastening, as in the case of the previous embodiment, first, the inner wrench 51 of the electric wrench 5 is fitted into the outer periphery of the nut 8 and the outer sleeve 52 is fitted into the outer periphery of the flat washer 2. Next, the electric wrench 5 is driven and the nut 8 is rotated by the inner wrench 51, while the outer sleeve 52 prevents the polygonal flat washer 2 from rotating together, and the convex washer 3 has the rotational torque of the nut 8. Tighten under unaffected conditions. Thereafter, when the axial force to be obtained lower than the yield point is reached, the convex portions 3b... 3b of the washer 3 with convex portions are completely crushed and the depression is completed, and at this time, the paint in the concave portions 3c. While oozing out to the outer periphery of the washer 3 with the convex portion through the grooves 3d. As the changed point, the controller 5 turns off the motor 53 and automatically stops the electric wrench 5. As a result, an axial force is applied to the washer 3 with the convex portion without being affected by the torque coefficient, and the axial force to be secured to the fastening member 6 of the fastened member 7 by the bolt 1 with the head is surely and accurately obtained. Can be done. In addition, whether or not the screw 8 has been tightened by introducing the axial force to be obtained by the nut 8 by visually confirming the seepage of the paint 4 to the outer peripheral portion due to the completion of crushing of the convex portions 3b. It is possible to confirm the tightening by visual inspection.

  As described above, when the nut 8 is screwed to the screw body 6b provided on the fastening member 6 and fastened, the screw fastening by the nut 8 can be reliably and accurately performed by the axial force to be obtained, and moreover, it should be obtained. Tightening confirmation as to whether or not the fastening is completed by introducing the axial force can be easily and reliably performed by visual confirmation. Therefore, this is an effective screw fastening method for fastening important portions that require tightening confirmation.

  It is explanatory drawing of the bolt with a head used with the screw fastening method which concerns on this invention, a polygonal flat washer, and a washer with a convex part.   It is a top view of a polygon-shaped plain washer.   It is a longitudinal cross-sectional view of a polygonal flat washer.   It is a bottom view of a washer with a convex part.   It is the sectional view on the AA line of FIG.   It is explanatory drawing which shows the shape change of the bolt with a head and the washer with a convex part with respect to axial force.   It is explanatory drawing at the time of screw fastening.   It is explanatory drawing at the time of completion | finish of screw fastening.   It is a top view which shows another embodiment of a polygonal flat washer.   It is explanatory drawing at the time of the screw fastening which shows another embodiment.

1 Bolt with Head 2 Polygonal Flat Washer 3 Washer with Projection 4 Fluid 5 Electric Wrench 51 Inner Wrench 52 Outer Wrench 8 Nut

Claims (1)

  A screw fastening method that enables proper tightening without being influenced by the torque coefficient, and is larger than the contour of the head or nut interposed so as to be relatively rotatable with respect to the tightening seat surface of the bolt or nut with head. Convex polygonal plain washer, and a convex intervening between the plain washer and the fastened member and having a plurality of convex portions on the front surface side and a plurality of concave portions corresponding to the respective convex portions on the back surface side Using an electric wrench having a washer with a portion, a rotating-side inner wrench that fits into the head or nut of a bolt with a head, and a fixed-side outer sleeve that fits into a polygonal flat washer, Each convex part is set so as to be completely crushed and depressed with the axial force to be obtained lower than the yield point of the bolt with which the head bolt or nut is screwed, while the visibility of paint or resin etc. in each recess Contain fluids with or When the screw is fastened, the inner wrench of the electric wrench is first engaged with the head or nut of the bolt with the head and the outer Insert the sleeve into the flat washer, and then drive the electric wrench to rotate the bolt or nut with the head with the inner wrench, while the outer sleeve prevents the polygonal plain washer from rotating together. Tighten under the condition that it is not affected by the rotational torque of the bolt or nut with head, and then reach the axial force that is required to be lower than the above yield point, each convex part of the washer with convex part is completely When the crushing is completed, the fluid in each of the recesses escapes to the outer periphery of the washer with a convex through the escape groove, and at the same time, the electric current wrench motor current change point accompanying the completion of the convex depression is charged. Screw fastening method, wherein to capture, the axial force to be determined by the head bolt or nut as a change point that is introduced, and so as to stop the electric wrench.

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