JP2009227112A - Automobile frame structure and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automobile frame structure with a plurality of pipe members extending in the axial direction for producing a consistently great collision energy absorbing amount by joining the pipe members to surely generate buckling deformation in the axial direction, and to provide its manufacturing method. <P>SOLUTION: Laser is generated by a laser oscillator 29 and supplied to an irradiation head 27. Laser L is emitted from the irradiation head 27 and reflected from a mirror 20 to heat a joint site through the inside of a cylinder pipe 11C for welding operation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automobile frame structure and a manufacturing method thereof, and more particularly, to an automobile frame structure and a manufacturing method thereof having improved collision energy absorption performance.

Conventionally, in the frame structure of an automobile, the front side frame and the rear side frame are buckled and deformed in the axial direction at the time of a collision to absorb the collision energy so that the influence of the collision is not exerted on the vehicle interior. Are known.
For this reason, in the frame structure of an automobile, a frame structure with high collision energy absorption performance is required.

For example, the following Patent Document 1 proposes a frame structure in which a frame cross section is divided into a plurality of cross sections by extrusion molding or the like.
According to this frame structure, the amount of collision energy absorption is increased and the buckling shape is stabilized, so that the effect of stabilizing the amount of collision energy absorption and buckling deformation at the time of deformation can be obtained.
However, according to the frame structure of the extrusion molding, there is a problem that the material to be processed and the manufacturing cost are high, and the productivity is deteriorated.

Therefore, a frame structure disclosed in Patent Document 2 has been proposed as a frame structure that prevents deterioration in productivity.
This frame structure is configured by filling a plurality of small-diameter pipe members and the like into a frame such as a rectangular closed section.
According to this frame structure, when a collision load is received, the pipe member in the frame is also buckled and deformed in the axial direction in the same manner as the frame, so that the amount of collision energy absorbed increases. In particular, since the pipe member is filled in the frame, it is described that the pipe members interfere with each other during buckling deformation, and the amount of collision energy absorbed is further increased. .
JP 2001-63626 A Japanese Patent Laid-Open No. 2003-31535

  By the way, in order to stably improve the collision energy absorption performance, it is necessary to always buckle and deform the frame structure in the axial direction.

  In this regard, in the frame structure of Patent Document 2 described above, the frame having a large cross section and the pipe member having a small cross section are simultaneously buckled and deformed. For example, the crushing period (repetition period of the fold and trough folds in the deformation direction) changes, and therefore, a phenomenon occurs in which the buckling period differs between the frame and the pipe member and the phase of deformation shifts.

  In this way, if the crushing period is different between the frame and the pipe member and the deformation phase shifts, the deformation behavior of each other will be inhibited, and the frame structure can be reliably buckled and deformed in the axial direction. There is a risk that lateral deformation or the like may occur.

  For this reason, it can be considered that the frame phase is eliminated by eliminating the frame positioned around the pipe member, and only the pipe members are assembled to form the frame structure, thereby eliminating such a problem of the displacement of the deformation phase.

  However, when the frame serving as the outer shell member is eliminated, it is necessary to connect the pipe members only by the pipe members, and there is a problem in what connection method is used to connect the pipe members.

  Therefore, the present invention provides an automobile frame structure including a plurality of pipe members extending in the axial direction and a method for manufacturing the same. It is an object of the present invention to provide a frame structure capable of obtaining an absorption amount and a manufacturing method thereof.

  An automobile frame structure according to the present invention is an automobile frame structure including a plurality of axially extending pipe members, wherein the pipe members are formed of cylindrical pipes having substantially the same cross section, and the cylindrical pipes are adjacent cylinders. It is welded with a laser that is irradiated from the inside of the pipe.

According to the said structure, the cylindrical pipe adjacent to a cylindrical pipe is welded with the laser irradiated from the inside of a pipe.
For this reason, joining between cylindrical pipes can be performed reliably, and cylindrical pipes can be reliably connected only by a cylindrical pipe.
In addition, as long as laser welding is performed from the inside of the cylindrical pipe, any welding position, irradiation amount, welding machine shape, irradiation head, and the like of laser welding may be used.

In one embodiment of the present invention, the laser welding is performed by scanning in a straight line in the axial direction of the cylindrical pipe.
According to the said structure, joining between cylindrical pipes can be performed more reliably by scanning in the straight line shape to the axial direction of a cylindrical pipe, and performing laser welding.
Therefore, it is possible to reliably increase the coupling force at the joining point between the cylindrical pipes, and to reliably prevent the peeling at the time of buckling deformation of the cylindrical pipe.

In one embodiment of the present invention, the laser welding is performed at a predetermined interval in accordance with the deformation phase of the buckling deformation of the cylindrical pipe.
According to the above configuration, by performing laser welding with a predetermined interval in accordance with the deformation phase of the buckling deformation of the cylindrical pipe, only the part where peeling occurs at the time of buckling deformation by joining the cylindrical pipes, It can be done efficiently.
Specifically, in consideration of the period of buckling deformation of the cylindrical pipe, a portion where peeling occurs is specified, and laser welding is performed in a so-called stitch shape.
Therefore, the cost of laser welding can be reduced while obtaining a stable buckling deformation at the time of buckling deformation.

In one embodiment of the present invention, a cylindrical pipe for irradiating a laser from the inside of the pipe is set as a central cylindrical pipe, and a plurality of peripheral cylindrical pipes to be joined are arranged around the central cylindrical pipe, respectively. Laser welding is performed by rotating the irradiation in the circumferential direction.
According to the said structure, the surrounding cylindrical pipe is arrange | positioned around a center cylindrical pipe, and the several joining point of a surrounding cylindrical pipe can be joined at once by laser-welding from the inside of a center pipe.
Therefore, joining a plurality of cylindrical pipes can be performed efficiently, and the manufacturing method of the frame structure can be performed more simply.

The manufacturing method of the automobile frame structure according to the present invention is a method in which a mirror movable in the axial direction is inserted into the pipe of the cylindrical pipe, and the laser beam of the laser welding is reflected by the mirror and bonded. is there.
According to the above configuration, by performing laser welding from the inside of the pipe using a mirror, if the mirror can be inserted, the inner diameter of the cylindrical pipe and the size of the laser welding machine are not taken into consideration. Laser welding can be performed.
Therefore, even when welding is performed from the inside of the cylindrical pipe, it is possible to perform manufacturing operations with improved versatility for cylindrical pipes having various diameters.

In one embodiment of the present invention, the laser welding is performed at a predetermined interval in accordance with the deformation phase of the buckling deformation of the cylindrical pipe, and simultaneously on different portions of the mirror in the axial direction of the cylindrical pipe. In this method, a plurality of lasers are reflected to join the cylindrical pipes with the predetermined interval.
According to the above configuration, laser welding can be performed by simultaneously reflecting a plurality of lasers at different portions of the mirror in the axial direction of the cylindrical pipe so that a plurality of locations are spaced apart at the same time.
For this reason, during so-called stitch-like laser welding, the amount of movement of the mirror in the cylindrical pipe can be reduced, and the welding work time can also be shortened.
Therefore, even when welding is performed with a predetermined interval, the frame structure can be welded with improved work efficiency.

In one embodiment of the present invention, the laser welding is performed at a predetermined interval according to the deformation phase of the buckling deformation of the cylindrical pipe, and the reflection angle of the mirror is changed with respect to the axial direction. In this method, an angle adjusting mechanism is provided, and a cylindrical pipe is joined by changing a reflection angle by the angle adjusting mechanism.
According to the above configuration, laser welding can be performed at predetermined intervals by changing the reflection angle of the mirror with the angle adjustment mechanism.
For this reason, a plurality of welding locations can be welded without moving the mirror in the axial direction during so-called stitch-shaped laser welding.
Therefore, even when welding is performed at a predetermined interval, the frame structure can be welded with improved work efficiency.

In one embodiment of the present invention, the cylindrical pipes are joined by inserting mirrors from the opening ends on both sides of the cylindrical pipe, irradiating a laser from each of the opening ends on both sides, and reflecting by the mirrors. It is a method to do.
According to the above configuration, by inserting mirrors from the opening ends on both sides of the cylindrical pipe, irradiating the laser from each opening end and reflecting and joining each mirror, even if the cylindrical pipe is long, Laser welding can be performed without increasing the amount of mirror insertion.
For this reason, variation in the welding position due to an increase in the amount of insertion of the mirror can be suppressed, and the accuracy of the welding position can be increased.
Therefore, even if the cylindrical pipe is long, welding can be reliably performed, and the coupling strength between the cylindrical pipes can be reliably increased.

In one embodiment of the present invention, a method of joining a central cylindrical pipe and a plurality of peripheral cylindrical pipes arranged around the central cylindrical pipe, the axis of the central cylindrical pipe being set as the rotation center of the mirror In this method, a rotating mechanism is provided, and the reflecting mechanism of the mirror is movable in the circumferential direction by the rotating mechanism, and the central cylindrical pipe and the peripheral cylindrical pipe are joined by reflecting the laser.
According to the above configuration, the central cylindrical pipe and the plurality of surrounding cylindrical pipes can be joined together by changing the reflection direction of the mirror in the circumferential direction and changing the laser irradiation position by the mirror rotation mechanism. .
Therefore, laser welding can be efficiently performed from the central cylindrical pipe, and welding work time can be shortened.

In one embodiment of the present invention, the joining is performed by inserting a laser fiber movable in the axial direction into the pipe of the cylindrical pipe and irradiating the laser from the tip of the laser fiber.
According to the said structure, since a laser can be directly irradiated to a joining position by performing laser welding from the inside of a pipe using a laser fiber, welding accuracy can be improved.
Therefore, even when welding is performed from the inside of the cylindrical pipe, the welding accuracy can be improved, and the joining strength between the cylindrical pipes can be increased.

In one embodiment of the present invention, the laser welding is performed at a predetermined interval according to the deformation phase of the buckling deformation of the cylindrical pipe, wherein a plurality of the laser fibers are set, and each laser fiber is set. This is a method in which the front end portion is set at a predetermined interval and a plurality of locations are joined simultaneously.
According to the above configuration, it is easy and reliable to perform laser welding at a predetermined interval by setting a plurality of laser fibers at predetermined intervals and joining a plurality of locations at the same time. Can be done.
Therefore, when laser welding is performed in a so-called stitch shape, the work efficiency can be increased and the frame structure can be welded.

An automobile frame structure according to the present invention is an automobile frame structure including a plurality of axially extending cylindrical pipes, wherein the cylindrical pipe is constituted by a cylindrical pipe having substantially the same cross-section, and the cylindrical pipe has a melting point. The cylindrical pipe is composed of a high inner member and an outer member having a low melting point, and the cylindrical pipes are joined together by the outer members.
According to the above configuration, since the cylindrical pipe can be joined at a relatively low temperature by joining the outer members having a low melting point, the cylindrical pipe can be used without affecting the shape of the inner member having a high melting point. Can be joined.
Therefore, a plurality of cylindrical pipes can be joined without causing distortion in the cylindrical pipe, and the behavior of buckling deformation when subjected to a collision load can be stabilized.

In one embodiment of the present invention, the cylindrical pipes are bundled in a final joined state and fired at an intermediate temperature that is higher than the melting point of the outer member and lower than the melting point of the inner member, thereby melting the contact portion of each cylindrical pipe. It is the method of making it join.
According to the said structure, a some cylindrical pipe can be bundled and it can fuse | melt and join between cylindrical pipes by baking at intermediate temperature.
For this reason, a cylindrical pipe can be joined at a relatively low temperature without using a welding machine such as laser welding.
Therefore, the buckling deformation behavior of the frame structure can be stabilized without causing distortion in the cylindrical pipe.

The automobile frame structure of the present invention is an automobile frame structure having a plurality of closed cross sections extending in the axial direction, wherein the closed cross section is formed of a cylindrical portion having a substantially equal cross section, and the frame is constricted. A first cylindrical member having a convex portion having a concave portion and a second cylindrical member having a concave portion having a constriction, and fitting and connecting the first cylindrical member and the second cylindrical member by the convex portion and the concave portion. Are combined.
According to the said structure, a flame | frame can be comprised by fittingly coupling a 1st cylindrical member and a 2nd cylindrical member with a convex part and a recessed part.
For this reason, since the heat treatment is not used for joining the cylindrical portions, the cylindrical portions are not distorted by the joining work.
Therefore, the buckling deformation behavior of the frame structure having a plurality of cylindrical portions can be stabilized.

In one embodiment of the present invention, the frame is configured to couple at least three cylindrical portions to each other, and one of the first cylindrical member and the second cylindrical member is integrally formed with a plurality of cylindrical portions. It is what has.
According to the above configuration, since one of the first cylindrical member or the second cylindrical member has a plurality of integrally formed cylindrical portions, the first cylindrical member or the second cylindrical member is not provided for each cylindrical portion. The frame can be configured.
Therefore, the number of parts of the frame having a plurality of cylindrical portions can be reduced and configured.

In one embodiment of the present invention, two sets of two cylindrical portions connected to each other are arranged at a distance from each other and the frame is connected to all the cylindrical portions at the center between the cylindrical portions. A structure in which two central cylindrical portions are arranged, and one of the first cylindrical member or the second cylindrical member has three cylindrical portions integrally formed with the central cylindrical portion and one cylindrical portion of each set. .
According to the above configuration, when having five cylindrical portions, one of the first cylindrical member or the second cylindrical member has three cylindrical portions integrally formed. The frame can be configured without providing two cylindrical members.
Therefore, a frame having a plurality of cylindrical portions can be configured with parts reduced.

In one embodiment of the present invention, the one cylindrical member is formed by integrally molding three cylindrical portions, that is, a central cylindrical portion and a cylindrical portion diagonal to the central cylindrical portion.
According to the said structure, when it has five cylindrical parts, one cylindrical member by which three cylindrical parts are integrally molded, and the other cylindrical member connected with this separately are arrange | positioned without bias. become.
Therefore, when the frame is buckled and deformed, a difference in strength is unlikely to occur, and the buckling deformation performance is stabilized.

In one embodiment of the present invention, the cylindrical pipe is formed by drawing or roll forming so as to have a plurality of cylindrical portions.
According to the said structure, the number of parts of a cylindrical pipe can be reduced by forming a some cylindrical part in the integrally formed cylindrical pipe by drawing or roll forming.
That is, since the number of cylindrical pipes can be reduced more than the number of cross sections, the number of parts can be reduced.

  According to the present invention, the joining between the cylindrical pipes can be performed reliably, and the cylindrical pipes can be reliably joined only by the cylindrical pipes.

  Therefore, in an automobile frame structure including a plurality of pipe members extending in the axial direction and a manufacturing method thereof, the pipe members are coupled so as to surely buckle and deform in the axial direction, and a large amount of collision energy is always obtained. be able to.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the first embodiment will be described. 1 is a front perspective view of a vehicle body front structure using the automobile frame structure of the present invention as a crash can, FIG. 2 is an overall perspective view of the crash can, FIG. 3 is a perspective view of a front end portion of the crash can, and FIG. It is a front view of a crash can. In the present embodiment, only the vehicle body structure at the right front is shown.

  As shown in FIG. 1, in the present embodiment, a front side frame 1 having a substantially rectangular cross section extending in the longitudinal direction of the vehicle body is provided at the front of the vehicle body. At the front end portion of the front side frame 1, a crush can 3 is provided that extends in the longitudinal direction of the vehicle body via a flat set plate 2. A bumper rain member 4 is provided at the front end of the crash can 3 so as to extend in the vehicle width direction and span the left and right crash cans 3 (the left side is not shown).

  A bent portion 5 that is bent downward and inclined is formed at the rear portion of the front side frame 1. A floor frame 6 extending in the longitudinal direction of the vehicle body is coupled and fixed to the lower end of the bent portion 5 on the lower surface of the vehicle body floor (not shown).

  An inclined connecting member 7 extending in an inclined manner is coupled and fixed to the vehicle width inner side surface of the bent portion 5 on the vehicle width inner side. The inclined connecting member 7 is fixedly joined to a dash cross member at the lower portion of a dash panel (not shown).

A suspension cross mounting bracket 8 for fastening and fixing a suspension cross member (not shown) is joined and fixed to the lower surface of the bent portion 5.
Further, an upper connecting member 9 that extends upward and rearward and is connected to a hinge pillar (not shown) is joined and fixed to the front upper surface of the bent portion 5.

  In this way, the rear portion of the front side frame 1 is reinforced, so that the collision load input to the front side frame 1 from the front of the vehicle body is distributed and transmitted to the rear side of the vehicle body.

  The aforementioned crash can 3 is constituted by a so-called “aggregate pipe body” in which a plurality of cylindrical pipes 11 are assembled and joined. As shown in FIG. 2, the crush can 3 composed of this collective pipe body is composed of five cylindrical pipes 11... With two upper parts 11A, 11B, two lower parts 11D, 11E and one central part 11C. It is configured in combination with a vertically long shape.

  Specifically, the crush can 3 is composed of five cylindrical pipes 11A, 11B, 11C, 11D, and 11E having the same diameter d (38 mm in this embodiment) formed of a steel material, in the vehicle longitudinal direction (vertical direction in the drawing). And adjacent cylindrical pipes are joined to each other as will be described later.

  The length of the crash can 3 in the front-rear direction is set to about 150 mm to ensure a crash space in the front-rear direction of the vehicle body. The plate thickness t (1 mm in this embodiment) of the cylindrical pipe is all the same.

  The crash can 3 is configured to buckle and deform in the axial direction and absorb collision energy when a load in the longitudinal direction of the vehicle body acts. In particular, since the crash can 3 simultaneously buckles and deforms five cylindrical pipes 11A, 11B, 11C, 11D, and 11E, the buckling load can be increased more than the conventional crash can, and the amount of energy absorption is increased. can do.

At the position of S (in this embodiment, about 15 mm) from the front end to the rear side of the collective pipe body, there are provided horizontal beads 12 that define the crushing shape of the crash can 3 when a collision load is applied. In addition, this S changes with the pitch of the crushing period of a cylindrical pipe.
This horizontal bead 12 is formed in an indented shape provided at an interval of about 120 degrees on all the cylindrical pipes 11. As will be described later, the lateral bead 12 provides a “crack” for buckling deformation when the crash can 3 undergoes buckling deformation.
In addition, as shown in FIG. 3, a plurality of joint portions 13, 14, 15, 16, 17, 18 for joining adjacent cylindrical pipes 11 are set in the crash can 3.
Specifically, the uppermost joint part 13 is set between the upper two parts 11A and 11B, and the upper part joint part is provided at two places 14 between the upper two parts 11A and 11B and the central one 11C. 15 and two lower joints 16 and 17 are set between the lower two pieces 11D and 11E and the central one 11C, and further, the lowermost part is placed between the lower two pieces 11D and 11E. A joining portion 18 is set.

  These joint portions 13, 14, 15, 16, 17, and 18 extend in a straight line over almost the entire region in the axial direction of the cylindrical pipe 11. By extending in this way, the joining strength between the cylindrical pipes 11 is increased.

As shown in FIG. 3, the positional relationship between the joint portions 13, 14, 15, 16, 17, and 18 is the upper three points, that is, the two portions 14, 15 of the uppermost joint portion 13 and the upper joint portion. The figure R formed by connecting the three points is set to be a “regular triangle”.
In addition, the lower part of the figure Q, that is, the figure Q formed by connecting the three points of the lower part joint part 18 and the two parts 16 and 17 of the lower part joint part is set to be an “inverted regular triangle”. Yes. The “regular triangle” R and the “inverted regular triangle” Q are set so as to be vertically symmetric with respect to the central cylindrical pipe 11C.
This is set to such a joining portion in consideration of the deformation behavior at the time of buckling deformation of the cylindrical pipe 11.
FIG. 4 is a schematic view showing a deformed state of the cross-sectional shape at the time of buckling deformation of the cylindrical pipe, (a) is a side view and AA cross-sectional view of the cylindrical pipe before buckling deformation, (b ) Are a side view, a BB cross-sectional view, and a CC cross-sectional view of the cylindrical pipe after buckling deformation. The cylindrical pipe model is also a steel pipe having a diameter of 38 mm and a plate thickness of 1 mm.

As shown to (a), the cylindrical pipe 11 has a perfect circular cylindrical cross section before buckling deformation.
When this cylindrical pipe 11 undergoes buckling deformation under the longitudinal load of the vehicle body, as shown in (b), the cross-sectional shapes are “regular triangles” and “ Repeat the "inverted regular triangle".

  This is because the smallest polygon that constitutes the “surface” is a triangle, and when the cylindrical cross-section is expanded to the outer peripheral side due to a compressive force, stress concentration occurs locally at three points. This is because it is considered that buckling deformation occurs by periodically repeating the “triangle” cross section and the “forward / reverse triangle” cross section.

  Thus, since the cross-sectional shape is deformed while repeating “regular triangle” and “regular triangle”, it is necessary to set the joining portion of the cylindrical pipe 11 so as not to inhibit the repeated deformation.

  Therefore, in this embodiment, as shown in FIGS. 5 and 6, the joint portion is set in consideration of the deformation state. FIG. 5 is a front view of the crash can obtained by adding a triangular deformation model whose right side is a vertex, and FIG. 6 is a front view of the crash can obtained by adding a triangular deformation model whose left side is a vertex.

  First, as shown in FIG. 5, in a portion where the cross-sectional shape is deformed into a triangle having the right side as a vertex, each joint portion moves as indicated by an arrow. That is, the uppermost joint part 13 moves to the right (13a), the right part 15 of the upper joint part moves to the lower left oblique side (15a), and the left part 14 moves to the upper left oblique side (14a). To do. Further, the lowermost joint part 18 moves to the right side (18a), the right side part 17 of the lower part joint part moves to the upper left diagonal side (17a), and the left side part 16 moves to the lower left diagonal side (16a). )

  On the other hand, as shown in FIG. 6, in a portion where the cross-sectional shape is deformed into a triangle having the left side as a vertex, each joint portion moves as indicated by an arrow. That is, the uppermost joint part 13 moves to the left (13b), the right part 15 of the upper part joint part moves to the upper right side (15b), and the left side part 14 moves to the lower right side (14b). To do. Further, the lowermost joint part 18 moves to the left side (18b), the right side part 17 of the lower part joint part moves to the lower right diagonal side (17b), and the left side part 16 moves to the upper right diagonal side (16b). )

As described above, the joint portions 13, 14, 15, 16, 17, and 18 reciprocate along the repeated deformation of the cross-sectional shape of the cylindrical pipe 11.
However, such a movement of the joining portion does not hinder the deformation of the cylindrical pipe 11 and can maintain the joined state between the cylindrical pipes 11.

  If each joining part is set to constitute a “regular rectangle”, the joining part does not move in accordance with the cross-sectional deformation of the cylindrical pipe 11, so that the buckling deformation of the cylindrical pipe 11 is inhibited, Moreover, there exists a possibility that joining between the cylindrical pipes 11 may peel.

  With respect to these points, in the present embodiment, as described above, the joint portions 13, 14, 15, 16, 17, and 18 are set so as to form an “equilateral triangle” and an “inverted equilateral triangle”. The buckling deformation of the crash can 3 can be allowed in a state where the joined state between the cylindrical pipes 11 is maintained.

As described above, since the joint portions 13, 14, 15, 16, 17, and 18 do not inhibit the buckling deformation of the crash can 3, the cylindrical pipe 11 is completely buckled and deformed in the crash can 3 of the present embodiment. The collision energy can be absorbed reliably.
FIG. 7 shows a state before and after buckling deformation of the crash can. FIG. 7A is a side view of the crash can before buckling deformation, and FIG. 7B is a side view of the crash can after buckling deformation.

  As shown to (a), the crush can 3 attached to the front-end part of the front side frame 1 via the set plate 2 is extended in the vehicle body front-back direction, and has secured the crash space of the vehicle body front-back direction.

On the front side surface of the crash can 3, the lateral bead 12 serving as the deformation promoting portion described above is provided.
The horizontal bead 12 is set to be the “side” of the “triangle” when the cross-sectional shape of the cylindrical pipe 11 is deformed to “triangle”. That is, by providing the lateral beads 12, the strength of the circumferential portion 19 where the lateral beads 12 are not provided is relatively increased. When a compressive load is applied, stress is applied to the circumferential portion 19. The deformation is concentrated so as to become the apex of the triangle, and as a result, the lateral beads 12 are set to be “sides”.

  A “lateral slit” may be provided instead of the horizontal bead 12. In the case of the “lateral slit”, the strength of the cylindrical portion without the horizontal slit is relatively increased, so that when a compressive load is applied, stress is concentrated on this circumferential portion and becomes the apex of the triangle. This is because deformation occurs, and as a result, the horizontal slit becomes the “side”.

  Thus, by forming the horizontal bead 12, the starting point and the cross-sectional shape of the crush cycle of the cylindrical pipe 11 can be defined, so that each cylindrical pipe 11 is buckled and deformed with the same cross-sectional shape in the same phase. become.

  As shown in (b), when receiving a collision load from the front of the vehicle body, the crash can 3 buckles and deforms in front of the front side frame 1. At this time, all the cylindrical pipes 11 are buckled and deformed in a similar manner by repeatedly performing a mountain fold and a valley fold in the axial direction.

  The pitch P of the collapse period of the buckling deformation depends on the diameter d when the plate thickness of the cylindrical pipe 11 is constant. The pitch P decreases as the diameter d decreases, and the pitch P increases as the diameter d increases. P also increases (in this embodiment, about 38 mm when not compressed).

In this embodiment, since the diameter d of the cylindrical pipe 11 is small, the pitch P of the crushing cycle is also small. As shown in the figure, the radial outer shape of the crash can 3 after buckling deformation is also a conventional square columnar shape. It is relatively smaller than a crash can.
In addition, since the pitch P of the crushing period is small, the amount of movement in the radial direction of the joint portion can be small, so that separation of the joint portion can be reliably prevented.

  FIG. 8 is a graph showing a comparison of collision energy absorption states of the crash can of the present embodiment and the conventional structure. This graph shows the buckling load on the vertical axis and the stroke amount on the horizontal axis.

  The load characteristic line of the crash can 3 of this embodiment is a characteristic line indicated by X. On the other hand, the load characteristic line of the conventional square columnar crash can 3 is a characteristic line indicated by Z.

As shown in this graph, the load characteristic X of the crash can 3 of the present embodiment shows the highest value in the load peak value Xp in the initial stage of the collision, and then strokes (crushes while maintaining a large absorption load). ) Go.
That is, it can be seen that the average load Xm of the present embodiment is about four times or more the load characteristic Z of the conventional structure, and the impact energy absorption performance is extremely higher than that of the conventional structure.
This is because, as mentioned above, five mass-absorbing impact absorbers, which are small-diameter cylindrical pipes with a small crushing cycle, are simultaneously buckled and deformed through the joints.
Therefore, according to the crash can 3 of the present embodiment, extremely high shock absorbing performance can be obtained.

Next, FIG. 9 will be used to explain how much the diameter and thickness of the crush can be buckled and deformed.
FIG. 9 is a graph showing a case where the crush can is buckled and deformed by changing the thickness and diameter of a cylindrical pipe having a length in the front-rear direction of about 150 mm. In this graph, the vertical axis indicates the diameter d of the cylindrical pipe 11 and the horizontal axis indicates the plate thickness t of the cylindrical pipe 11.

  In this graph, ◯ indicates a case where the cylindrical pipe is buckled and deformed with a triangular cross section, and × indicates a case where the cylindrical pipe is buckled and deformed except for a triangular cross section. As for the hatched dot region, the dense dot region is a region where all the cylindrical pipes are buckled and deformed in a triangular cross section, and the sparse dot region is a region where the sparse dot region is buckled and deformed in a triangular cross section and a square cross section. Further, a region without hatching is a region where buckling deformation does not occur, and a region where collision energy is hardly absorbed due to lateral bending deformation or the like.

  As far as the range of this graph is concerned, it can be seen that the region where the cylindrical pipe is deformed into a triangular cross section has a thickness t of 0.4 to 2.0 mm and a diameter d of 20 to 80 mm. Further, it can be seen that if the plate thickness t is thin even with the same diameter d, it is deformed not only with a triangular cross section but also with a square cross section. Furthermore, it can be seen that even when the diameter d is small or too large even with the same plate thickness t, the triangular cross section may not be crushed.

When the plate thickness t is 1.0 mm and the diameter d is 38 mm as in the present embodiment (T), it can be seen that all the cylindrical pipes 11 are surely buckled and deformed in a triangular cross section.
From these facts, in order to effectively carry out the present invention, it can be seen that it is desirable to construct the crush can 3 by designing a cylindrical pipe with the plate thickness t and diameter d of the dense dot region of this graph. .

Next, based on FIG. 10, the manufacturing method of the crush can of this embodiment, especially the joining method between cylindrical pipes are demonstrated.
FIG. 10 is an overall schematic view of a welding machine that joins the cylindrical pipes of the crush can of the first embodiment. The welder M1 is a so-called laser welder, and performs welding by irradiating a laser L to overheat the welded portion. In this embodiment, a mirror laser welding machine M1 that performs welding by reflecting the irradiated laser L by using the mirror (mirror) 20 is used.

The system configuration of the mirror laser welding machine M1 includes a rotating device 21 attached to a base (not shown), a reference fixed shaft 22 fixed to the rotating device 21 and extending in the vertical direction, and fixed in the middle of the reference fixed shaft 22. The two fixed guides 24, 24 that support the lifting device 23 and the like, the lifting shaft 25 that is supported by the fixing guides 24, 24 and extends in the vertical direction, and the lifting shaft 25 that is provided in the middle of the lifting shaft 25 is moved up and down. A lifting device 23 that moves up and down movably in the direction, a mirror 20 that is provided at the lower end of the lifting shaft 25 and reflects the irradiated laser L, and a mirror 20 that is provided between the mirror 20 and the lifting shaft 25. A mirror angle adjusting device 26 that changes the reflection angle (tilt angle), an irradiation head 27 that is fixed to the lifting device 23 and irradiates the laser L toward the mirror 20, and And a laser oscillator 29 for supplying the laser L via the optical fiber 28 against the elevation head 27.
And among these, the rotating device 21, the raising / lowering device 23, the mirror angle adjusting device 26, and the operation panel 30 which controls the laser oscillator 29 by remote operation are provided. In addition, since the detailed structure of each component is well-known, specific description is abbreviate | omitted.

  The above-mentioned reference fixed shaft 22 is installed so as to be positioned on the concentric shaft CL with the cylindrical pipe 11 </ b> C at the center of the crash can 3. By installing the reference fixed shaft 22 at this position, as will be described later, it is possible to join all of the joining portions 14, 15, 16, and 17 located around the central cylindrical pipe 11C from within the cylindrical pipe 11C. it can.

Next, the joining method of the cylindrical pipe 11 performed using this mirror laser welding machine M1 is demonstrated.
First, using a jig (not shown), the five cylindrical pipes 11 are assembled in a final coupled state and set so that the axial direction is directed vertically. Then, as described above, the reference fixed shaft 22 is installed above the crush can 3 and on the concentric shaft of the central cylindrical pipe 11C.
Next, the lifting device 23 is operated to lower the lifting shaft 25. Thus, the mirror 20 is inserted into the central cylindrical pipe 11C. By this insertion, the mirror 20 is positioned at a position opposite to the joining portion in the cylindrical pipe 11C.

Then, the laser L generated by the laser oscillator 29 is supplied to the irradiation head 27, and the laser L is irradiated from the irradiation head 27. The irradiated laser L is reflected by the mirror 20 and heats and welds the joining portion 14 from the inside of the cylindrical pipe 11C (see FIG. 11).
Thereafter, the lifting device 23 is operated to gradually lower the lifting shaft 25, thereby lowering the mirror 20 and lowering the irradiation position of the laser L, that is, the welding position. Thus, laser welding is scanned in a straight line in the axial direction of the cylindrical pipe 11.
In addition, as shown in FIG. 12, the irradiation angle of the laser L is lowered by gradually widening the reflection angle α of the mirror 20 using the mirror angle adjusting device 26, and laser welding is linear in the axial direction. You may do so.

  Thereafter, the rotating device 21 is operated to rotate the reference fixed shaft 22 in the circumferential direction. As a result, the mirror 20 is moved to a position corresponding to the next joining portion 15 (see FIG. 3). Further, by irradiating the laser L from the irradiation head 27, the laser L is reflected by the mirror 20, and laser welding is also performed at the joining portion 15.

  Further, also in the joining portion 15, laser welding is performed in a straight line in the axial direction of the cylindrical pipe 11 using the lifting device 23 or the mirror angle adjusting device 26.

  Thereafter, the other two joining portions 16 and 17 (see FIG. 3) are similarly reflected by irradiating the laser L after rotating the mirror 20 in the circumferential direction using the rotating device 21. By doing so, laser welding between the cylindrical pipes 11 is performed.

  In this way, all four joint portions 14, 15, 16, and 17 of the central cylindrical pipe 11C can be welded only by rotating the irradiation position of the mirror 20 in the circumferential direction using the rotating device 21. Thereby, the insertion operation | work etc. of the mirror 20 can be skipped and work efficiency can be aimed at.

  After welding the joint portion of the central cylindrical pipe 11C, the mirror 20 is once pulled out of the central cylindrical pipe 11C, and again, the mirror 20 is attached to any of the other peripheral cylindrical pipes 11A, 11B, 11D, and 11E. Insert and weld the two joint portions 13 and 18 (see FIG. 3) between the surrounding cylindrical pipes.

  In this way, the welding between the cylindrical pipes 11 is completed by performing the welding operation of the six joining portions 13, 14, 15, 16, 17, and 18.

Next, the effect of this embodiment comprised in this way is demonstrated.
The crush can 3 of this embodiment is constituted by a plurality of cylindrical pipes 11 having the same cross section, and the cylindrical pipes 11 are welded to the adjacent cylindrical pipes 11 by a laser L irradiated from the inside of the pipes.

Thereby, the cylindrical pipe 11 adjacent to the cylindrical pipe 11 can be welded only by the laser L irradiated from the inside of the cylindrical pipe 11.
For this reason, the coupling between the cylindrical pipes 11 can be reliably performed, and the cylindrical pipes 11 can be reliably coupled only by the cylindrical pipe 11.
Therefore, in the crash can 3 including a plurality of pipe members extending in the axial direction, the cylindrical pipe 11 can be coupled so as to surely buckle and deform in the axial direction, so that a large amount of collision energy can be always obtained.

In this embodiment, the welding by the laser L is performed by scanning in a straight line in the axial direction of the cylindrical pipe 11.
Thereby, the joining between the cylindrical pipes 11 can be more reliably performed over the entire axial direction of the cylindrical pipes 11.
Therefore, it is possible to reliably increase the bonding force of the joint portions 13, 14, 15, 16, 17, and 18 between the cylindrical pipes 11, and to reliably prevent the peeling of the cylindrical pipe 11 during buckling deformation.

Further, in this embodiment, the laser L is irradiated from the inside of the central cylindrical pipe 11C, and the irradiation direction of the laser L is rotated in the circumferential direction, thereby joining the peripheral cylindrical pipes 11A, 11B, 11D, and 11E. is doing.
Thereby, it is possible to join all the joining portions of the central cylindrical pipe 11C and the surrounding cylindrical pipes 11A, 11B, 11C, and 11D at a time without taking out the mirror 20 from the central cylindrical pipe 11C.
Therefore, joining between the plurality of cylindrical pipes 11 can be performed efficiently, and the manufacturing method of the crash can 3 can be performed more simply.

Further, in this embodiment, a rotating device 21 having the center of rotation CL coincided with the axis CL of the central cylindrical pipe 11C is provided so that the reflecting direction of the mirror 20 can be rotated in the circumferential direction. By comprising, the center cylindrical pipe 11C and the surrounding cylindrical pipes 11A, 11B, 11D, and 11E are joined.
Thereby, the central cylindrical pipe 11C and the plurality of surrounding cylindrical pipes 11A, 11B, 11D, and 11E can be joined at a stretch only by changing the reflection position of the mirror 20.
Therefore, laser welding can be efficiently performed from the central cylindrical pipe 11C, and the welding operation time can be shortened.

Moreover, in this embodiment, the mirror 20 which can move to an axial direction is inserted in the pipe of the cylindrical pipe 11, and the laser L of laser welding is reflected with this mirror 20, and it joins.
As a result, if the mirror 20 can be inserted, laser welding can be performed between the cylindrical pipes 11 without considering the inner diameter of the cylindrical pipe 11 and the size of the laser welding machine M1.
Therefore, even when welding is performed from the inside of the cylindrical pipe 11, the versatility of the cylindrical pipe 11 having various diameters can be improved and manufacturing operations can be performed.

  In this embodiment, the joining portions are set in a straight line in the axial direction of the cylindrical pipe 11, but in addition, the joining positions are separated at every half pitch of the buckling deformation, so-called “stitching”. May be laser welded.

  In this way, by laser welding in a stitch shape, only the apex portion where separation is likely to occur when the cross-sectional shape is deformed into a triangle can be intensively welded, so that the welding operation can be performed efficiently. it can.

  In the welding of this embodiment, for example, as shown in FIG. 12, the stitch-shaped welding is performed by using a mirror angle adjusting device 26 to fix the mirror 20 at every predetermined angle and irradiate laser. It is conceivable to weld in a stitch shape by reflecting L.

In this case, only the portion where peeling occurs during buckling deformation can be performed efficiently.
Therefore, the cost of laser welding can be reduced while obtaining a stable buckling deformation at the time of buckling deformation.

In particular, by changing the reflection angle α of the mirror 20 with the mirror angle adjusting device 26 and welding the stitches in a stitch shape, it is possible to weld a plurality of welding locations without moving the mirror 20 in the axial direction.
Therefore, it is possible to further weld the cylindrical pipe 11 with improved working efficiency.
Further, when laser welding in a stitch shape, as shown in FIG. 13, it is conceivable to weld two joint portions 14A and 14B simultaneously using a large mirror 20A.
That is, a large mirror 20A having a reflecting surface 20Aa that is long in the axial direction of the cylindrical pipe 11 is set, and two lasers L1 and L2 are irradiated from two irradiation heads (not shown), respectively. By reflecting L1 and L2, it is conceivable to simultaneously join the upper joint portion 14A and the lower joint portion 14B.

  In this case, even if the joining locations 14A and 14B are spaced apart in a stitch shape, the two joining locations 14A and 14B can be joined simultaneously without raising and lowering the large mirror 20A.

In this way, it is also conceivable that two lasers L1 and L2 are simultaneously reflected on different portions of the reflecting surface 20Aa of the large mirror 20A in the pipe axis direction and welded in a stitch shape.
In this case, laser welding can be performed with a predetermined interval between the two joint portions 14A and 14B at the same time.
For this reason, when performing stitch-like laser welding, the amount of movement of the large mirror 20A can be reduced, and the welding work time can also be shortened.
Therefore, even when stitch welding is performed, the cylindrical pipe 11 can be welded with improved work efficiency.

Furthermore, as shown in FIG. 14, when the cylindrical pipe 11 is long, mirrors 20 and 20 are inserted from both side opening ends 11a and 11b of the cylindrical pipe 11 so that the laser L is cylindrical. By irradiating from the opening ends 11a and 11b on both sides of the pipe 11, it is conceivable to configure the joining portions 14C and 14D to be joined.
In this way, when the mirror 20 is inserted from both side open ends 11a and 11b of the cylindrical pipe 11 and laser welding is performed, the length of the cylindrical pipe 11 is long, and insertion from one side of the cylindrical pipe 11 Even if it is a case where a position cannot be specified reliably, it can weld reliably in desired joining location 14C, 14D.

As described above, the mirror 20 is inserted from the opening ends 11 a and 11 b on both sides of the cylindrical pipe 11, the laser L is irradiated from the opening ends 11 a and 11 b on both sides, and reflected by the mirrors 20 and 20. It is also conceivable to join the pipes 11 together.
In this case, even if the cylindrical pipe 11 is long, laser welding can be performed without increasing the insertion amount of the mirror 20.
For this reason, variations in the welding position due to an increase in the insertion amount of the mirror 20 can be suppressed, and the accuracy of the welding position can be increased.
Therefore, even if the cylindrical pipe 11 is long, welding can be reliably performed, and the coupling strength between the cylindrical pipes 11 can be reliably increased.

Further, when the amount of irradiation of the laser L of the welding machine is small, as shown in FIG. 15, a plurality of mirrors 20 are inserted from both side opening ends 11a, 11b of the cylindrical pipe 11, and one joint location is obtained. It is also conceivable that the laser L is concentrated and reflected on 14E to perform laser bonding.
In this case, since the plurality of mirrors 20 are inserted and the plurality of lasers L and L are concentrated and reflected at one joint location, the amount of irradiation of each laser L and L is small. Also, the cylindrical pipe 11 can be reliably welded.
Therefore, even when the irradiation amount of the laser L is small, the joint 14E can be reliably welded by using the plurality of mirrors 20.

Next, an embodiment of the second embodiment will be described with reference to FIG. FIG. 16 is an overall schematic diagram of the laser welding machine of the second embodiment.
The laser welding machine M2 of this embodiment is a so-called fiber laser welding machine M2 in which an irradiation head 31 is provided at the lower end of the lifting shaft 25 and a laser is guided to the irradiation head 31 by an optical fiber 32 (laser fiber). In addition, about another structure, since it is the same as that of the mirror laser welding machine M1 of 1st embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The optical fiber 32 is provided between the irradiation head 31 and the laser oscillator 29 as described above. The optical fiber 32 is a relatively long optical fiber, and is configured to reliably supply a laser to the irradiation head 31 even when the irradiation head 31 is inserted into the cylindrical pipe 11.

  The method of joining the cylindrical pipe 11 by the fiber laser welding machine M2 is also substantially the same as that of the first embodiment, and is the same as that except that the irradiation head 31 directly irradiates the laser L. .

As described above, in the present embodiment, the optical fiber 32 that is movable in the axial direction is inserted into the pipe of the cylindrical pipe 11, and the laser L is irradiated from the irradiation head 31 at the tip of the optical fiber 32, thereby joining. I try to do it.
Thereby, since the laser L can be directly irradiated to the joining site | part 14 (refer FIG. 3) with the irradiation head 31, a welding precision can be improved.
Therefore, even when welding is performed from the inside of the cylindrical pipe 11, the welding accuracy can be improved, and the joining strength between the cylindrical pipes 11 can be increased.

In this embodiment, a related embodiment as shown in FIG. 17 can be considered. FIG. 17 is an overall schematic diagram of a laser welder according to a related embodiment.
In the laser welding machine M3 of this embodiment, three irradiation heads 33 (33, 33, 33) are provided in the middle of the lifting shaft 25, and the three irradiation heads 33, 33, 33 are respectively provided. This is a fiber laser welding machine M3 provided with a plurality of laser oscillators 35, 35, 35 for connecting the corresponding optical fibers 34, 34, 34 and supplying laser to the respective optical fibers 34, 34, 34.
In addition, since it is the same as that of the mirror laser welding machine M1 of 1st embodiment about another structure, also in this welding machine M3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The irradiation heads 33 in this embodiment are provided in the middle of the lifting shaft 25 with an interval corresponding to a half pitch of buckling deformation. Thus, by installing the irradiation heads 33 with an interval corresponding to the half pitch of buckling deformation, stitch-shaped laser welding can be performed using this interval.

  The joining method of the cylindrical pipe 11 by the fiber laser welder M3 is the same as that of the second embodiment except that the three irradiation heads 33 ... irradiate lasers L ... simultaneously.

  In this way, the three irradiation heads 33 provided at intervals are irradiated with the laser L at the same time, so that stitch-like laser welding can be performed relatively easily.

Thus, in this embodiment, three optical fibers 34 are set, and the three irradiation heads 35 connected to the optical fibers 34 are installed at intervals corresponding to a half pitch of buckling deformation. At the same time, three locations are joined.
Thereby, it is possible to easily and reliably perform the stitch-like laser welding.
Therefore, in the case of stitched laser welding, it is possible to perform welding with improved work efficiency.
Note that the number of optical fibers and irradiation heads is not limited to three, and may be two, four, or even five.

  Next, a third embodiment will be described with reference to FIG. FIG. 18 is a cross-sectional view of the crash can of the third embodiment.

  The coupling structure of the crash can 103 of this embodiment is configured such that the cylindrical pipe 41 has a “double tube” structure in which the outer peripheral side is made of a low melting point alloy (42) and the inner peripheral side is made of a high melting point alloy (43). Using the difference in melting point, only the low-melting point alloy on the outer peripheral side is melted and fired to bond the cylindrical pipes 41.

  Specifically, as shown in FIG. 18, each cylindrical pipe 41 is formed with an inner cylindrical portion 43 formed with a high melting point aluminum alloy on the inner peripheral side and with a low melting point aluminum alloy such as aluminum silicon on the outer peripheral side. The outer cylindrical portion 42 is composed of a set double tube.

As shown in the figure, the cylindrical pipe 41 composed of the double pipes is assembled and bundled in a final bonded state, and in a melting furnace (not shown), the melting point temperature and the low melting point of the high melting point aluminum alloy (43). It is melted and fired at an intermediate temperature between the melting points of the aluminum alloy (42).
By this firing, the double-pipe cylindrical pipe 41 is melted only by the low melting point aluminum alloy (42) and is joined only by the contact portions 44 of the adjacent cylindrical pipes 41.
Thereby, the refractory aluminum alloy (43) is not melted at all during the joining operation, and no distortion due to heat occurs.

As described above, in the present embodiment, the cylindrical pipe 41 includes the inner cylindrical portion 43 made of a high melting point aluminum alloy having a high melting point, and the outer cylindrical portion 42 made of a low melting point aluminum alloy having a low melting point, and an intermediate temperature. The cylindrical pipes 41 are joined to each other by the outer cylindrical portions 42 by firing.
Thereby, since the cylindrical pipe 41 can be joined at a relatively low temperature, the cylindrical pipe 41 can be joined without affecting the shape of the inner cylindrical portion 43 having a high melting point.
Therefore, the plurality of cylindrical pipes 41 can be joined without causing distortion in the cylindrical pipe 41, and the behavior of buckling deformation when subjected to a collision load can be stabilized.

  In this embodiment, the entire outer peripheral side is covered with the low melting point aluminum alloy. However, only the portion corresponding to the joining portion may be covered with the low melting point aluminum alloy.

  Next, a fourth embodiment will be described with reference to FIGS. 19 is a cross-sectional view of the crush can of the fourth embodiment, FIG. 20 is a cross-sectional view of the crush can of another example, (a) is a cross-sectional view of the crush can of the first example, (b ) Is a cross-sectional view of the second example of a crash can.

  The crush can 203 of this embodiment does not connect a general cylindrical pipe, but a plurality of extruded frames (51, 52, 53) having a cylindrical portion are connected to an engaging concave portion 54 having a constriction and an engaging convexity. It is configured by fitting and coupling with the portion 55.

Specifically, as shown in FIG. 19, a plurality of extrusion frames (51, 52, 53) each having a cylindrical portion formed by extruding an aluminum alloy are set and fitted to each other, whereby the crash can. 203 is configured.
The extrusion frame is composed of a first frame 51 formed by integrally forming three cylindrical portions of a central cylindrical portion 50C, an upper left cylindrical portion 50B, and a lower left cylindrical portion 50E, and a second frame formed only by the upper right cylindrical portion 50A. 52 and a third frame 53 formed by only the lower left cylindrical portion 50D.

  On the side surface of the first frame 51, four engagement convex portions 54 each having a constriction are provided at portions contacting the second frame 52 and the third frame 53. On the other hand, the second frame 52 and the third frame 53 are also provided with two engagement recesses 55 each having a constriction so as to correspond to the engagement projections 54.

  Thus, the first frame 51, the second frame 52, and the third frame 53 are fitted and coupled using the engaging convex portions 54 and the engaging concave portions 55.

  In this way, the first frame 51, the second frame 52, and the third frame 53 are coupled using the engagement convex portions 54... And the engagement concave portions 55. Since the extrusion frame (51, 52, 53) is not heated, distortion in the extrusion frame can be prevented.

As described above, the crush can 203 according to this embodiment includes an extrusion frame composed of cylindrical portions 50A, 50B, 50C, 50D, and 50E having the same cross section and the engagement convex portion 54 having a constriction. The first frame 51, the second frame 52, and the third frame 53 are engaged with each other. The projection 54 and the engagement recess 55 are configured to be fitted and coupled.
Thereby, the crush can 203 provided with the plurality of cylindrical portions 50A, 50B, 50C, 50D, and 50E can be configured simply by fitting and coupling the engaging convex portion 54 and the engaging concave portion 55.
For this reason, since heat treatment is not used for joining the cylindrical portions 50A, 50B, 50C, 50D, and 50E, the cylindrical portions 50A, 50B, 50C, 50D, and 50E are not distorted by the joining work.
Therefore, the buckling deformation behavior of the crash can 203 having the plurality of cylindrical portions 50A, 50B, 50C, 50D, and 50E can be stabilized.

In this embodiment, the first frame 51 is formed by integrally molding three cylindrical portions 50B, 50C, and 50E.
Thereby, the crush can 3 provided with several cylindrical part 50A, 50B, 50C, 50D, 50E can be comprised, without providing an extrusion frame for every cylindrical part 50A, 50B, 50C, 50D, 50E.
Therefore, the crash can 3 having the plurality of cylindrical portions 50A, 50B, 50C, 50D, and 50E can be configured with parts reduced.

  In this embodiment, the three cylindrical portions 50B, 50C, and 50E are integrally formed on the first frame 51. However, for example, the first frame 51 may be integrally formed with two cylindrical portions. Moreover, although the engagement convex part 54 is provided in the 1st frame 51, you may provide an engagement recessed part in a 1st frame conversely.

As another example of the structure of the crash can, as shown in FIG. 20 (a), the first frame 51 is formed only by the central cylindrical portion 50C, and the upper right cylindrical portion 50B and the upper left cylindrical portion 50B are formed. The second frame 52 may be configured by two, and the third frame 53 may be configured by two of the lower right cylindrical portion 50D and the lower left cylindrical portion 50E.
Also in this case, a plurality of cylindrical portions 50A, 50B, 50C, 50D, and 50E are provided by fitting and coupling the engagement convex portions 54 provided in the respective frames 51, 52, and 53 with the engagement concave portions 55. It is conceivable to configure the crash can 303.

  In the case of the crash can 303, the second frame 52 and the third frame 53, which are integrally formed with the cylindrical portion, are positioned symmetrically in the vertical direction, and therefore, between the cylindrical portions 50A, 50B, 50C, 50D, and 50E. Can be made uniform in the vertical direction, and the behavior of the cylindrical portions 50A, 50B, 50C, 50D, 50E during buckling deformation can be matched in the vertical direction.

  Therefore, the buckling deformation of the crash can 303 does not occur in any way up and down, and the collision energy can be stably absorbed.

As another example of the structure of the crash can, as shown in (b), the first frame 51 is integrally formed of a central cylindrical portion 50C, an upper right cylindrical portion 50A, and a lower left cylindrical portion 50E. It is also conceivable that the second frame 52 is constituted only by the upper left cylindrical part 50B and the third frame 53 is constituted only by the lower right cylindrical part 50D.
Also in this case, it is conceivable that the crash can 403 is configured by fitting and coupling the engaging convex portions 54 and the engaging concave portions 55 provided on the respective frames 51, 52, and 53.

In the case of the crash can 403, two cylindrical portions (an upper right cylindrical portion 50A and a lower left cylindrical portion 50E) that are diagonal to the central cylindrical portion 50C are integrally formed by the first frame 51. Therefore, in the case of having five cylindrical portions, the first frame 51 in which the three cylindrical portions are integrally formed, and the second frame 52 and the third frame 53 that are separately connected to the first frame 51 are arranged without deviation. Will be.
Therefore, when the crash can 403 is buckled and deformed, a difference in strength is unlikely to occur, and the buckling deformation performance is stabilized.

  In addition, although not specifically shown, the five cylindrical portions may be configured as separate bodies, and may be configured to be fitted and connected by the engaging convex portion and the engaging concave portion.

  Next, a fifth embodiment will be described with reference to FIG. FIG. 21 is a detailed cross-sectional view of the joint between the cylindrical pipes of the fifth embodiment.

  In this embodiment, as shown in FIG. 21, the coupling portion that couples the cylindrical vipes 61, 61 includes a spline-like engagement boss portion 62 formed on the peripheral surface of the cylindrical pipe 61 and a spline-like engagement groove portion 63. And are connected by fitting.

  Specifically, an engagement boss portion 62 that extends in the axial direction in a spline shape and an engagement groove portion 63 that extends in the axial direction in a spline shape are formed on the peripheral surface of the cylindrical pipe 61 by plastic working or the like. Adjacent cylindrical pipes 61 and 61 are connected to each other by fitting and fixing the joint boss 62 and the engaging groove 63.

  The engagement boss portion 62 and the engagement groove portion 63 are each formed with a burr inclination angle β so that the fitting and fixing cannot be removed. Once fitted, the coupling and fixing between the cylindrical pipes 61 cannot be removed. It is configured.

As described above, in this embodiment, the engagement boss portion 62 and the engagement groove portion 63 are provided on the peripheral surface of the cylindrical pipe 61 for fitting and coupling. Therefore, in the coupling, as in the fourth embodiment, heat treatment is performed. There is no need to do.
Therefore, the cylindrical pipe 61 is not distorted by the coupling work, and the behavior of the buckling deformation of the crash can can be stabilized.

  Next, a sixth embodiment will be described with reference to FIG. FIGS. 22A and 22B are schematic views for explaining a method for forming a cylindrical pipe according to the sixth embodiment. FIG. 22A is a cross-sectional view of a forming apparatus, and FIG.

  In this embodiment, a pipe member having two cylindrical portions is formed from a pipe material 71 having an elliptical cross section by drawing. That is, by forming two cylindrical portions from a single pipe member, the number of cylindrical pipes used in the crash can is reduced while ensuring the number of cross sections of the cylinder.

  In this drawing process, as shown in (a), a drawing die 72 for drawing, a plug 73 disposed in the pipe member 71, a cylindrical holder 74 for holding a cylindrical shape, and a drawing for pulling the pipe member 71 are performed. And a drawing apparatus M4 including the machine 75.

  When the metal pipe member 71 is formed by the drawing device M4, as shown in FIG. 5B, a pipe member 71B in which two cylindrical portions 71a and 71b are arranged side by side from an elliptical pipe material 71A having a horizontally long cross section. Can be molded.

Thus, in this embodiment, the number of pipe members can be reduced by forming the pipe member 71B having two cylindrical portions 71a and 71b by such a processing method.
Therefore, since the number of pipe members can be reduced more than the number of cross sections, the number of parts can be reduced.
In addition, the shaping | molding apparatus of Fig.22 (a) illustrated the outline, and does not limit an apparatus structure.

  Next, a seventh embodiment will be described with reference to FIG. FIG. 23 is a schematic diagram for explaining a method for forming a cylindrical pipe according to the seventh embodiment. FIG. 23A is a side view of the forming apparatus, and FIG. 23B is a cross-sectional view at the time of forming including the pipe member.

  In this embodiment, a pipe member having two cylindrical portions is formed from a pipe member 81 having an elliptical cross section by roll forming. That is, by forming two cylindrical portions from a single pipe member, the number of cylindrical pipes used in the crash can is reduced while ensuring the number of cross sections of the cylinder.

  In this roll forming process, as shown in (a), the upper and lower Soroban bead-shaped upper and lower rollers 82 and the left and right drum-shaped left and right rollers 83 are gradually moved in the conveying direction of the pipe member 81. A plurality of roll forming machines arranged so as to narrow down are used.

  When the metal pipe member 81 is formed by this roll forming apparatus, a pipe member 81B in which two cylindrical portions 81a and 81b are arranged side by side from an elliptical pipe member 81A having a horizontally long cross section as shown in FIG. Can be molded.

Thus, also in this embodiment, the number of pipe members can be reduced by forming the pipe member 81B having two cylindrical portions 81a and 81b by such a processing method.
Therefore, since the number of pipe members can be reduced more than the number of cross sections, the number of parts can be reduced.
In addition, the shaping | molding apparatus of FIG. 23 shows the outline, and does not limit an apparatus structure.

  Next, an eighth embodiment will be described with reference to FIGS. FIG. 24 is a schematic diagram for explaining a method of forming a cylindrical pipe according to the eighth embodiment, FIG. 25 is a cross-sectional view of a preform laminated type cylindrical pipe, and FIG. 26 is another laminated type having a different preform shape. FIG. 27 is a cross-sectional view of a cylindrical pipe, and FIG. 27 is a cross-sectional view of a preform-integrated type cylindrical pipe.

In this embodiment, in order to more stably buckle and deform the cylindrical pipe constituting the crush can, the cylindrical pipe is formed using a substantially cylindrical preform, and the strength difference is partially applied in the cylindrical pipe. It is something that has
That is, for example, a preform formed with a reinforcing fiber described in JP-A-2007-268586 is set in a mold, and the preform is cast with a metal base material to form a cylindrical pipe. To do.

Specifically, the cylindrical pipe is formed by the forming step shown in FIG.
First, as shown in (a), a sheet-like preform 91 having thick portions 92 at equal intervals is formed. As described above, the preform 91 is formed from reinforcing fibers.

Next, as shown in (b), the sheet-like preform 91 is bent into a cylindrical shape to form a cylindrical preform 93. At this time, it shape | molds so that the thick part 92 ... may be located in an outer peripheral side.
In addition, you may make the shape of (b) from the beginning using a type | mold.

  Thereafter, as shown in (c), the cylindrical pipes are cut at a length corresponding to the half pitch of the buckling deformation, and the phases shifted by 60 degrees are laminated one by one (94).

  Finally, as shown in (d), the laminated preform 94 is set in a mold (not shown), and a base material (aluminum or the like) is poured into the cylindrical pipe 95 to form it.

  By forming the cylindrical pipe 95 in this way, the cylindrical pipe 95 is arranged such that the aluminum 96 as a base material is positioned on the outer peripheral side and the composite portion 97 of aluminum and preform is positioned on the inner peripheral side. Molded.

  Moreover, as shown in 1-1 longitudinal cross-sectional view, in the part which provided the thick part 92, the composite part 97 of aluminum and preform is comprised so that it may be repeatedly shape | molded by uneven | corrugated shape, 2-2. As compared with the longitudinal sectional view, it can be seen that the composite portion increases in the thick portion 92.

  In this way, by forming the cylindrical pipe 95, as shown by a one-dot chain line in FIG. 25, at the time of buckling deformation, the portion that becomes the side K1 of the triangle is deformed so as to be just the thick portion 92. That is, since the strength of the portion provided with the thick portion 92 is increased and the strength of the other portions is relatively decreased, stress concentration occurs in the low strength portion, and a triangular vertex K2 is formed in the portion. As a result, a triangular side K <b> 1 is generated in the thick portion 92.

  Therefore, according to the cylindrical pipe 95 of the present embodiment, the cross-sectional shape at the time of buckling deformation can be reliably defined, so that the buckle deformation of the crash can can be caused more stably.

  Next, FIG. 26 is a cross-sectional view of another cylindrical pipe with a different shape of the preform, (a) is a cross-sectional view when the preform is positioned on the inner peripheral side, and (b) is an outer periphery of the preform. It is sectional drawing at the time of being located in the side.

  In this embodiment, the recesses 101 are formed at intervals of about 120 degrees in a part of the cylindrical preform 100, and an equilateral triangle vertex K2 is formed in the recesses 101 during buckling deformation. ing.

  As shown in (a), when the preform 100A is positioned on the inner peripheral side, three concave portions 101A that are recessed by one step are formed on the outer surface side at intervals of 120 degrees. Thereby, at the time of buckling deformation, as shown by a one-dot chain line, an equilateral triangle in which the vertex K2 is located is formed in the recess 101A.

  As shown in (b), when the preform 100B is positioned on the outer peripheral side, three concave portions 101B are formed on the inner surface side at intervals of 120 degrees. Thereby, at the time of buckling deformation, as shown by a one-dot chain line, an equilateral triangle in which the vertex K2 is located is formed in the recess 101A.

  In any of the drawings, the concave portion 101C indicated by a broken line indicates a concave portion corresponding to the vertex of the inverted equilateral triangle after a half pitch.

  In this way, when the preform 100 is molded, the concave portion 101 can reliably define the vertex K2 of the equilateral triangle at the time of buckling deformation, and therefore, more than the shape of the preform 97 shown in FIG. The behavior of the cylindrical pipe 101 during buckling deformation can be stabilized.

  Therefore, in this embodiment, the collision energy absorption performance can be improved more stably.

  Next, FIG. 27 is a cross-sectional view of a preform-integrated type cylindrical pipe, where (a) is a cross-sectional view when the preform is positioned on the inner peripheral side, and (b) is a position where the preform is positioned on the outer peripheral side. FIG.

  In this embodiment, concave portions 111 are formed at intervals of about 60 degrees in a part of the cylindrical preform 110, and at the time of buckling deformation, a vertex K2 of an equilateral triangle and a vertex K3 of an inverted regular triangle are formed in the concave portion 111. It is configured to be formed.

  As shown in (a), when the preform 110A is positioned on the inner peripheral side, six recesses 111 recessed by one step are formed on the outer surface side at intervals of 60 degrees. Thereby, the equilateral triangle X1 is formed at the time of buckling deformation, as shown with a dashed-dotted line. Further, an inverted equilateral triangle X2 is formed at the next half pitch as shown by a broken line.

  As shown in (b), when the preform 110B is positioned on the outer peripheral side, six recesses 111B that are recessed one step are formed on the inner surface side at intervals of 60 degrees. Thereby, the equilateral triangle X1 is formed at the time of buckling deformation, as shown with a dashed-dotted line. Further, an inverted equilateral triangle X2 is formed at the next half pitch as shown by a broken line.

Thus, when the preform 110 is integrally molded, it is not necessary to cut and laminate the preform 110, so that the moldability of the cylindrical pipe can be improved.
Further, since the concave portion 111B can reliably define the vertex K2 of the regular triangle X1 and the vertex K2 of the inverted regular triangle X2 during buckling deformation, the behavior of the cylindrical pipe during buckling deformation can be stabilized.

  Therefore, in the case of this embodiment, the moldability of the cylindrical pipe can be improved, and the collision energy absorption performance can be improved more stably.

As described above, in the correspondence between the configuration of the present invention and the above-described embodiment,
The angle adjustment mechanism of the present invention corresponds to the mirror angle adjustment device 26 of the embodiment,
Similarly,
Laser fiber corresponds to optical fiber 32,
The inner member corresponds to the inner cylindrical portion 43,
The outer member corresponds to the outer cylindrical portion 42,
The first cylindrical member corresponds to the first frame 51,
The second cylindrical member corresponds to the second frame 52,
The present invention is not limited to the above-described embodiments, but includes embodiments applied to any automobile frame structure.

  For example, not only the crash can at the front of the vehicle body, but also a crash can at the rear of the vehicle body, a front side frame that is a skeleton member of the vehicle body, or a rear side frame may be used.

The front perspective view of the vehicle body front part structure which used the frame structure of the motor vehicle as a crash can. The whole perspective view of a crash can. The perspective view of the front-end part of a crash can. Front view of the crash can. The figure which added the deformation model of the triangle which appoints the right side to the front view of a crash can. The figure which added the deformation model of the triangle which makes the left side a vertex to the front view of a crash can. It is a side view which shows the state before buckling deformation of a crash can and after buckling deformation, (a) is a side view of the crash can before buckling deformation, (b) is a side view of the crash can after buckling deformation. . The figure which showed the graph which compares the collision energy absorption state of the crash can of this embodiment and the crash can of a conventional structure. The figure which showed the graph at the time of carrying out buckling deformation of the crush can by changing the plate | board thickness and diameter of a cylindrical pipe. The whole schematic diagram of the welding machine which joins between the cylindrical pipes of the crash can of 1st embodiment. The schematic diagram of the state which reflects a laser with a mirror and welds. The schematic diagram of the state which changed the reflective angle of the mirror using the mirror angle adjustment apparatus. The schematic diagram of the state which reflects a laser with a large mirror and welds. The schematic diagram of the state which inserts a mirror from the both ends opening part of a cylindrical pipe, and welds. The schematic diagram of the state which reflects and reflects a laser using a some mirror. The whole schematic diagram of the laser welding machine of 2nd embodiment. The whole schematic diagram of the laser welding machine of related embodiment. The cross-sectional view of the crash can according to the third embodiment. The cross-sectional view of the crash can of 4th embodiment. It is a cross-sectional view of the crush can of another example, (a) is a cross-sectional view of the crush can of the first example, (b) is a cross-sectional view of the crush can of the second example. Detailed sectional drawing of the connection part between the cylindrical pipes of 5th embodiment. It is a schematic diagram explaining the shaping | molding method of the cylindrical pipe of 6th embodiment, (a) is sectional drawing of a shaping | molding apparatus, (b) is sectional drawing at the time of shaping | molding of a cylindrical pipe. It is a schematic diagram explaining the shaping | molding method of the cylindrical pipe of 7th embodiment, (a) is a side view of a shaping | molding apparatus, (b) is sectional drawing at the time of the shaping | molding also including the pipe member. The schematic diagram explaining the shaping | molding method of the cylindrical pipe of 8th embodiment. Sectional drawing of a preform lamination type cylindrical pipe. Sectional drawing of the other laminated type cylindrical pipe from which preform shape differs. Sectional drawing of a preform-integrated type cylindrical pipe.

Explanation of symbols

L ... Laser 1 ... Front side frame 3,103,203,303,403 ... Crash can 11,11A, 11B, 11C, 11D, 11E ... Cylinder pipe 20,20A ... Mirror 26 ... Mirror angle adjusting device 32, 35 ... Optical fiber 42 ... Outer cylindrical portion 43 ... Inner cylindrical portion 51 ... First frame 52 ... Second frame 53 ... Third frame

Claims (18)

An automobile frame structure including a plurality of axially extending pipe members,
The pipe member is composed of a cylindrical pipe having substantially the same cross section,
A frame structure of an automobile in which the cylindrical pipe is welded to an adjacent cylindrical pipe with a laser irradiated from the inside of the pipe. The automobile frame structure according to claim 1, wherein the welding by the laser is performed by scanning in a straight line in the axial direction of the cylindrical pipe. The automobile frame structure according to claim 1, wherein the laser welding is performed at a predetermined interval in accordance with a deformation phase of buckling deformation of the cylindrical pipe. A cylindrical pipe that irradiates a laser from the inside of the pipe is set as a central cylindrical pipe,
A plurality of surrounding cylindrical pipes to be joined to each other are arranged around the central cylindrical pipe,
4. The automobile frame structure according to claim 2, wherein laser welding is performed by rotating a laser irradiation position in a circumferential direction. Inserting an axially movable mirror inside the cylindrical pipe,
The method for manufacturing a frame structure according to any one of claims 1 to 4, wherein the joining is performed by reflecting the laser welding laser with the mirror. The laser welding is a method of performing a predetermined interval according to the deformation phase of the buckling deformation of the cylindrical pipe,
The manufacturing method according to claim 5, wherein a plurality of lasers are simultaneously reflected on different portions of the mirror in the axial direction of the cylindrical pipe, and the cylindrical pipes are joined at the predetermined interval. A method of performing the laser welding at a predetermined interval according to the deformation phase of the buckling deformation of the cylindrical pipe,
The manufacturing method according to claim 5, wherein the mirror includes an angle adjustment mechanism that changes a reflection angle with respect to an axial direction, and the cylindrical pipe is joined by changing the reflection angle by the angle adjustment mechanism. Inserting mirrors from both ends of the cylindrical pipe,
The manufacturing method according to any one of claims 5 to 7, wherein the cylindrical pipe is joined by irradiating a laser from each of the opening ends on both sides and reflecting the laser beam by each mirror. A method of joining a central cylindrical pipe and a plurality of peripheral cylindrical pipes arranged around the central cylindrical pipe,
The mirror includes a rotation mechanism with the center of the central cylindrical pipe as the rotation center,
The rotating mechanism is configured to move the reflection direction of the mirror in the circumferential direction,
The manufacturing method according to claim 5, wherein the central cylindrical pipe and the peripheral cylindrical pipe are joined by reflecting the laser. Insert a laser fiber movable in the axial direction inside the cylindrical pipe,
The manufacturing method of the frame structure according to any one of claims 1 to 4, wherein joining is performed by irradiating a laser from a tip portion of the laser fiber. A method of performing the laser welding at a predetermined interval according to the deformation phase of the buckling deformation of the cylindrical pipe,
Set multiple laser fibers,
The manufacturing method according to claim 10, wherein a tip portion of each laser fiber is set at the predetermined interval and a plurality of locations are joined simultaneously. An automobile frame structure comprising a plurality of axially extending cylindrical pipes,
The cylindrical pipe is constituted by a cylindrical pipe having substantially the same cross section,
An automobile frame structure in which the cylindrical pipe is composed of an inner member having a high melting point and an outer member having a low melting point, and the cylindrical pipes are joined to each other by the outer members. Bundle cylindrical pipes together in the final joined state
Firing at an intermediate temperature higher than the melting point of the outer member and lower than the melting point of the inner member,
The method for manufacturing a frame structure according to claim 12, wherein the contact portions of the cylindrical pipes are melted and joined. A frame structure of an automobile having a plurality of closed cross sections extending in an axial direction,
The closed cross section is constituted by a cylindrical portion of a cylindrical shape having substantially the same cross section,
A first cylindrical member provided with a convex portion having a constriction on the frame;
Consists of a second cylindrical member provided with a recess having a constriction,
A frame structure of an automobile in which the first cylindrical member and the second cylindrical member are joined by fitting and connecting at a convex portion and a concave portion. The frame is configured to couple at least three cylindrical portions to each other,
The automobile frame structure according to claim 14, wherein one of the first cylindrical member and the second cylindrical member has a plurality of cylindrical portions integrally formed. The frame has a structure in which two cylindrical parts connected to each other are arranged at a distance from each other, and one central cylindrical part connected to all the cylindrical parts is arranged in the center between the cylindrical parts. There,
The automobile frame structure according to claim 15, wherein one of the first cylindrical member and the second cylindrical member has three cylindrical portions integrally formed of a central cylindrical portion and one cylindrical portion of each set. 17. The automobile frame structure according to claim 16, wherein the one cylindrical member is integrally formed with three cylindrical parts, a central cylindrical part and a cylindrical part diagonal to the central cylindrical part. The automobile frame structure according to claim 1 or 12, wherein the cylindrical pipe is formed by pultrusion molding or roll molding so as to have a plurality of cylindrical portions.

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