JP2012035810A - Exterior beam for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exterior beam for a vehicle, capable of preventing co-rotation of a fastening member with a simple structure, and thereby reliably fixing it.SOLUTION: In the exterior beam 100 for a vehicle in which a diameter-expanded part 25 bulging outward in a radial direction is formed by buckling a peripheral wall 24 of a self locking nut 20 inserted into a mounting hole 11 of a beam body 10 to thereby fix the self locking nut 20 to the beam body 10, the mounting hole 11 has an oblong hole shape, and part of the peripheral wall 24 of the self locking nut 20 is deformed along the oblong hole shape of the mounting hole 11.

Description

  The present invention relates to an exterior beam for a vehicle such as a bumper disposed in a vehicle.

  In general vehicles such as trucks having a high vehicle height, a bumper is provided below the vehicle in order to prevent a car from falling when a low vehicle height collides. This bumper is generally formed in a square tube shape from steel, aluminum alloy, or the like, and is used by fastening with a bolt or the like when attached to a vehicle.

For example, Patent Literature 1 proposes a fastening method in which a pierce nut is driven into a plate-shaped wall of an aluminum alloy extruded profile from the inside of the hollow and fixed to the plate-shaped wall.
The pierce nut is a nut that is driven into a metal plate that supports the back surface with a caulking die with a driving punch, and the metal plate is punched out with the nut itself, and at the same time, the periphery of the punched hole is caulked and fixed to the metal plate. In this pierce nut, if the caulking force is small, it may fall off from the plate-like wall, and the bolt tightening operation may not be performed well. Therefore, in order to install the pierce nut, it is necessary to configure a plate-like wall having a thickness that can be punched by the nut itself and can withstand the caulking force.
Then, although the cross-sectional shape and plate | board thickness are set according to the impact load assumed for a plate-shaped wall, in the pierce nut of patent document 1, other part of the plate-like wall in which a pierce nut is driven is another A thick part having a thickness greater than that of the part is formed to increase the caulking force.

  Further, as a method of joining a bumper formed of an aluminum alloy or the like and a frame member, a fastening method using a caulking nut as proposed in Patent Document 2 is known. In this case, after the caulking nut is caulked and fixed around the through hole of the bumper, the bolt can be screwed into the caulking nut through the through hole of the frame member and fastened.

JP 2010-18061 A JP 2008-175380 A

Incidentally, in recent years, in order to reduce the weight of the bumper, the peripheral wall of an extruded material such as an aluminum alloy has been formed to be relatively thin.
Therefore, when the pierce nut shown in Patent Document 1 is used for fastening the bumper, the caulking force is secured by forming the peripheral portion including the driving portion thick, and the driving portion itself is punched through. Need to be formed.
In addition, since the limit torque of the pierce nut is low and the pierce nut and the bolt are likely to rotate together, it is difficult to fasten with the high torque.

  Even when the caulking nut shown in Patent Document 2 is used for fastening the bumper, it is easy to cause co-rotation at the caulking portion. To prevent co-rotation, the caulking nut is knurled or the diameter of the prepared hole is strictly set. Measures such as management are necessary.

  The present invention has been made in view of such circumstances, and provides an exterior beam for a vehicle that can prevent the fastening member from rotating together with a simple configuration and can be reliably fixed.

  The exterior beam for a vehicle according to the present invention includes a caulking nut inserted into the mounting hole of the beam body to buckle a peripheral wall portion of the caulking nut to form a diameter-expanded portion that bulges outward in the radial direction, thereby causing the caulking nut to move toward the beam. A vehicle exterior beam fixed to a main body, wherein the mounting hole has an elongated hole shape, and a part of a peripheral wall portion of the caulking nut is deformed and provided along the elongated hole shape of the mounting hole. It is characterized by being.

  When the caulking nut is inserted into the mounting hole, the vehicle exterior beam formed in this way forms a gap at both ends in the longitudinal direction of the mounting hole. In this state, when the peripheral wall portion of the caulking nut is bulged and fixed, a part of the peripheral wall portion bites into the gap and is deformed and caulked. Since the biting portion functions as a rotation stopper, when the exterior beam is attached to the vehicle, it is possible to reliably prevent the caulking nut and the fastening bolt from rotating together, and the exterior beam can be firmly fixed.

In the vehicle exterior beam of the present invention, the mounting hole may have a ratio of a length in the longitudinal direction to a length in the width direction of 1.1 or more and 1.4 or less.
In this way, by setting the shape of the elongated hole of the mounting hole, the circumferential wall portion of the caulking nut can surely bite into the gap between the mounting hole and the caulking nut, and the caulking nut and the fastening bolt can rotate together. It can be surely prevented.
When the ratio of the length in the longitudinal direction to the length in the width direction is less than 1.1, the above-described gap is too small, and the caulking nut is not sufficiently bitten and the function as a rotation stopper cannot be obtained sufficiently. On the other hand, when the ratio exceeds 1.4, the caulking nut bites more and misalignment is likely to occur.

  ADVANTAGE OF THE INVENTION According to this invention, although it is the simple structure which makes the attachment hole of a beam main body a long hole shape, the joint beam of a fastening member can be prevented and the exterior beam for vehicles which can be fixed reliably can be provided. .

It is a perspective view of the exterior beam of this embodiment. It is a figure explaining an attachment hole. It is a principal part enlarged view of the exterior beam shown in FIG. 1, (a) is a top view, (b) is a side view. It is AA sectional drawing of the exterior beam shown in FIG. 3, (a) shows before fixing, (b) shows after fixing. It is a schematic block diagram of the limit torque evaluation apparatus of a caulking nut.

Hereinafter, an embodiment of a vehicle exterior beam according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the vehicle exterior beam 100 according to the present embodiment is configured by fixing a caulking nut 20, which is a fastening member, in an attachment hole 11 of a beam body 10 formed in a rectangular tube shape.

As shown in FIG. 1, the beam body 10 is formed in a rectangular tube shape by extrusion molding of an aluminum alloy, and is formed to have a length comparable to the width dimension of the vehicle to be attached.
A mounting hole 11 for inserting and fixing a caulking nut 20 is provided on the peripheral wall of the beam body 10.
As shown in FIG. 2, the mounting hole 11 has a long hole shape, where the length in the longitudinal direction is a long diameter L, and the length in the width direction perpendicular to the longitudinal direction is a short diameter S. The ratio L / S (long hole ratio) of the long diameter L to S is 1.1 to 1.4. Further, both end portions in the longitudinal direction of the mounting hole 11 have an arc shape having a diameter that is substantially the same as the short diameter S.

  As shown in FIG. 4A, the caulking nut 20 is formed of a cylindrical cylindrical body 21, and has a flange portion 22 at one end thereof. The front end of the cylindrical body 21 is formed thick, and a female screw portion 23 is formed inside thereof. And between the internal thread part 23 and the flange part 22 of the cylindrical body 21, it is the surrounding wall part 24 formed by making the opening diameter larger than the front-end | tip of the cylindrical body 21, and thinly.

The caulking nut 20 configured as described above is fixed to the beam body 10 as follows.
First, as shown in FIG. 4A, when the caulking nut 20 is inserted into the mounting hole 11 of the beam body 10 and the flange portion 22 is brought into contact with the outer wall of the beam body 10, the longitudinal direction of the mounting hole 11 is increased. A gap 11a is formed at both ends. In this state, the fastening bolt 30 is inserted from the flange portion 22 side and screwed into the female screw portion 23, and the flange portion 22 is fixed with a caulking tool (not shown) and tightened to tighten the cylindrical body 21. The distal end is drawn toward the inner wall side of the beam body 10 and the thin peripheral wall portion 24 bulges outward in the radial direction and buckles, as shown in FIGS. Is formed. When the fastening bolt 30 is further tightened, the wall of the beam main body 10 is clamped between the flange portion 22 and the enlarged diameter portion 25 of the caulking nut 20 and caulked. At this time, a part of the peripheral wall portion 24 bites into the gap 11 a between the mounting hole 11 and the caulking nut 20 at a portion inserted into the mounting hole 11 from the end face of the enlarged diameter portion 25 of the swollen caulking nut 20. It is deformed and fixed along the elongated hole shape of the hole 11.

  When the exterior beam 100 configured as described above is attached to the vehicle, the biting portion 25a into the gap 11a in the peripheral wall portion 24 of the caulking nut 20 functions as a rotation stopper, so that the caulking nut 20 and the fastening bolt 30 rotate together. Can be reliably prevented, and the exterior beam 100 can be firmly fixed.

Next, an embodiment according to the vehicle exterior beam of the present invention will be described.
As shown in FIG. 2, the length of the mounting hole 11 in the longitudinal direction is defined as the major axis L, the length in the width direction perpendicular to the longitudinal direction is defined as the minor axis S, and the mounting is performed under the conditions shown in Table 1 instead of the beam body. Sample pieces 15 in which the holes 11 were formed were produced, and the caulking nuts 20 were fixed to the respective sample pieces 15 to confirm the mounting strength of the caulking nuts 20 fixed to the respective sample pieces 15.
The “long hole ratio” in Table 1 is the ratio L / S of the long diameter L to the short diameter S. It shows that the long diameter L is formed longer than the short diameter S as the value of the long hole ratio L / S increases. For example, when the long hole ratio L / S is 1, it is the case where the short diameter S and the long diameter L are the same length, which indicates that the shape is not a long hole shape but a circular shape.

  As the sample piece 15, an aluminum alloy plate having a thickness of 10 mm is used, and as shown in FIG. 5, the steel plate 40 is overlapped and fixed to each sample piece 15 to which the caulking nut 20 is attached. The fastening bolt 30 inserted from above is screwed into the caulking nut 20, and torque is applied to the fastening bolt 30 with a torque wrench 50, so that the caulking nut 20 and the fastening bolt 30 rotate together, or the screw is broken or the fastening bolt 30 is broken. Until then, torque was continuously applied to the fastening bolt 30. The results are shown in Table 1.

  “◯” in Table 1 indicates a sample piece in which torque can be continuously applied until screw breakage occurs without occurrence of co-rotation or misalignment. Co-rotation indicates that the fastening bolt 30 and the caulking nut 20 rotate together, and misalignment means that the axial center of the mounting hole 11 of the sample piece 15 and the male screw portion of the caulking nut 20 is displaced, resulting in the fastening bolt. 30 indicates that only halfway can be inserted.

As shown in Table 1, when the long hole ratio L / S is 1 and the circular mounting hole 11 is co-rotating, the long hole ratio L / S is 1.1 or more and 1.4 or less. In the case of (1), the co-rotation did not occur, and the fastening bolt 30 could be tightened until the screw break occurred. The maximum torque at this time was all 45 N · m or more, and was firmly fixed.
On the other hand, if the long hole ratio L / S is too large (1.5 or more), the fastening bolt 30 may be tightened to the end when the flange portion 22 of the caulking nut 20 is deformed or misalignment occurs. could not.

  As described above, when the long hole ratio L / S is less than 1.1, the gap 11a cannot be sufficiently secured at both ends in the longitudinal direction of the mounting hole 11, and the circumferential wall portion 24 of the caulking nut 20 is provided with the gap 11a. Since it cannot be engulfed, the function as a detent may not be sufficiently obtained. Further, when the ratio exceeds 1.4, a part of the peripheral wall portion 24 of the caulking nut 20 falls into the gap 11a, or the flange portion 22 of the caulking nut 20 is deformed, so that the caulking nut 20 is caulked. Since an adverse effect such as a shift of the shaft center with the nut 20 may occur, the long hole ratio L / S of the mounting hole 11 is preferably set to 1.1 or more and 1.4 or less.

In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, a various change can be added in the range which does not deviate from the meaning of this invention.
In the above embodiment, both ends in the longitudinal direction of the mounting hole are formed in an arc shape having a diameter that is substantially the same as the minor axis S. However, both ends in the longitudinal direction of the mounting hole are formed in a planar shape, and the mounting hole You may comprise by a rectangle.

In the above embodiment, the case where the vehicle exterior beam is attached to the vehicle has been described. However, the present invention is also used when peripheral components such as a lamp, a license plate, and a harness are attached to the vehicle exterior beam. .
Further, the present invention can be applied not only to a beam main body formed in a rectangular tube shape but also to a beam main body having a C-shaped cross section having no hollow portion, for example.

DESCRIPTION OF SYMBOLS 100 Vehicle exterior beam 10 Beam main body 11 Mounting hole 11a Clearance 15 Sample piece 20 Caulking nut 21 Cylindrical body 22 Flange part 23 Female thread part 24 Peripheral wall part 25 Expanded part 25a Biting part 30 Fastening bolt 40 Steel plate 41 Insertion hole 50 Torque wrench

Claims (2)

  A vehicular exterior formed by fixing the caulking nut to the beam body by buckling the peripheral wall portion of the caulking nut inserted into the mounting hole of the beam body to form a diameter-expanded portion bulging outward in the radial direction. A vehicle exterior, wherein the mounting hole has a long hole shape, and a part of a peripheral wall portion of the caulking nut is deformed along the long hole shape of the mounting hole. beam.   The exterior beam for vehicles according to claim 1, wherein a ratio of a length in the longitudinal direction to a length in the width direction of the mounting hole is 1.1 or more and 1.4 or less.

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