JPH11244936A - Manufacture of short tube having force-fitting chamfer part in both ends - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for manufacturing a short tube having a tapered surface of a force-fitting chamfer from a hoop material. SOLUTION: A hoop material 1A is set to an uncoiler, the stress of a coil is removed through a leveler, and a tapered surface 2a1 equivalent to a force-fitting chamfer is plastically deformed in either surface of the upper surface or rear surface of the width part of the hoop material 1A. An excess part of the plastically deformed place is notched and cut at the length 2b1 wherein undecided width parts 2b2, 2c2 are left from the prepared length in the radial direction of a short tube. Further, a blank 2A is made by being cut at the prepared length, next the orthogonal direction of the taper is bent into a cylindrical body, the undecided width parts 2b2, 2c2 are clamped with a jig and positioned, an abutted place is welded by laser beams, and the bead part by the laser beam welding is finished up. Next, after the undecided width parts 2b2, 2c2 are press cut so as to coincide with the end surface of the cylindrical body, the inside and outside are cleaned, the end surface part and the cylindrical part are straightened by a die, and the whole processes are completed. Thus, the short tube is manufactured from the hoop material through such a series of manufacturing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a part of an automobile part, which is a short pipe part having a chamfering taper for press-fitting at both outer and inner diameters at both ends. The present invention relates to a method for manufacturing an inexpensive short pipe made by utilizing plastic working and laser welding.

[0002]

2. Description of the Related Art As shown in FIG.
As a method of manufacturing a part having a tapered press-fitting chamfer at one end of either the outer diameter or the inner diameter as shown in FIG. 5 at 0b, a steel pipe subjected to a drawing process is generally machined to a predetermined length. Then, the end surfaces of both ends are finished and the above-mentioned chamfering process is performed on the outer diameter portion or the inner diameter portion.

[0003]

In the conventional manufacturing method, pipe-forming, drawing, cutting, both end faces and chamfering from hoop material are performed independently of each other. Because they are shared by specialized industries, there was no consistent view from the materials. As one of the concerns, for example, regarding yield loss, in pipe making, unwelded parts at the time of setup change, bulging parts of beads due to welding, chucking parts at the time of pipe drawing, fixed size cutting by machining There are many items of material loss from hoop material to finished parts, such as cutting width at the time, remaining material, end surface finishing allowance, chamfered part, etc.In addition, intermediate production by batch production is required, such production equipment is expensive For this reason, I thought that there would be a simpler and cheaper manufacturing method than hoop material.

Considering the function of a steel pipe as a press-fitting part, the rolling direction of the hoop material (fiber flow inside the material) is the longitudinal direction of the pipe because the steel pipe continuously forms the hoop material. When pressed into a component, the direction of the compressive force applied to the component is orthogonal. In order to make use of the characteristics of the fiber flow, it was considered that the compression strength was increased in the same direction as the compression direction after the insertion, the reliability of the compression was improved, and the weight could be reduced.

In view of the above, there is a tapered surface for press-fitting chamfering at either the outer diameter or the inner diameter as described above, and a short pipe without burrs is provided at the other corners without cutting chips from the hoop material. Considering that it is possible to manufacture a production line with inexpensive capital investment, the method of forming a tapered surface for press-fitting chamfering, when a blank made of hoop material is formed into a cylindrical body, the butted part becomes an outwardly open V-groove and When laser welding, the bead portion is reduced in thickness. In laser welding, because the allowable range of misalignment between the part to be welded and the laser torch in welding is small, there is a lack of penetration due to penetration at the start and end points during welding of the laser welder. There are issues such as the handling of meat and the process organization in consideration of the direction of the fiber flow of the material.

[0006]

Means for Solving the Problems In order to solve the above problems,
The first feature of the present invention is to adjust the circumferential direction of the short pipe to the rolling direction of the hoop material so that the overall length of the short pipe is determined by the direction of the hoop width. The second feature is that the tapered surface of the press-fitting chamfer is Both ends of the hoop material with a predetermined width are plastically deformed by a plate-shaped mold with a tapered surface corresponding to the chamfer of the short tube, and the surplus portion is unwidth-determined at both ends of the charged length of the short tube. The third characteristic is that, when bent into a cylindrical body, the butt surface does not become an outwardly open V-groove, so that it is perpendicular to the taper surface. Before bending into a cylindrical body, the end face of the blank is pre-bent away from the end face so as not to be affected by bending stress, and after intermediate bending, when further formed into a cylindrical body, the end faces are perpendicular to each other. To match.

The fourth feature is that, as described above, the positioning of the welding portion and the removal of the welded portion at the start and end points of the welding are performed by press-fitting the taper into either the upper surface or the lower surface of the hoop material. The surface is plastically deformed, and the excess part of the formed part is cut by the width of the entire length of the short pipe, and this cut leaves undetermined parts at both ends in the direction perpendicular to the tapered forming surface, and it is bent into a cylindrical body When this is done, the unwidth-determined portions come to both ends of the butted portion, and the position of the welded portion can be automatically determined by clamping with a jig so as to sandwich the unwidth-determined portion. Since the unfinished portion of the start and end points protrudes beyond the entire length of the short pipe, it is generated at the protruding point, and the unwidth-determined portion is press-cut to weld the start and end points during welding. The notch can be removed.

[0008]

By solving the above-mentioned problems, the production method of the present invention reduces the yield loss of short pipes having a press-fitting chamfering taper as compared with the conventional manufacturing method of cutting and chamfering drawn steel pipes. By arranging processing equipment that can be manufactured and is suitable for the processing method of each process, it is possible to construct a manufacturing line with a small space and a small investment regardless of large-sized equipment.

When the roundness of the steel pipe is inferior as an advantage in the press-fitting characteristic, if the end face is chamfered by cutting,
The boundary with the cutting surface meanders. In the initial stage of the press-fitting, the meandering portion does not uniformly hit the receiving portion of the other party, and extreme pressure is generated at a portion where the meandering portion is in partial contact, so that it is easy to cause galling. Since the plate material is plastically deformed by a plate-shaped mold having a tapered surface corresponding to the chamfered surface of a short pipe, it does not meander when it is bent into a cylindrical body, so that the occurrence of galling can be reduced. Further, by setting the rolling direction of the hoop material and the circumferential direction of the short pipe in the same direction, it is expected that the compressive strength is improved.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a production line from a hoop material to a finished product, which constitutes the production method of the present invention. In the present invention, the hoop material is used in order to maximize the above-mentioned target material properties, and the steps are organized so that the rolling direction matches the circumferential direction of the short pipe. In the first step, a hoop material having a predetermined width is set on an uncoiler, and the residual stress of the coil is removed through a leveler. In the second step, both sides of the hoop material are
The both sides of the hoop are plastically deformed with a plate-shaped mold having a tapered surface corresponding to the chamfer surface for press fitting of the short pipe, or a stepped roll having a tapered angle, and the plastic deformation point is set to the length of the short pipe. The blank is cut at both end portions while leaving undetermined portions, and cut into the radial length of the short pipe to obtain a blank.

In a third step, the blank is preformed by a bend die into a cylindrical body, a butt portion of the cylindrical body is laser-welded in a fourth step, an outer diameter part in a fifth step, and an inner diameter part in a sixth step. In the seventh step, the non-width-determined portion is cut, and in the eighth step, the spatter and the like generated at the time of laser welding are removed by washing. In the ninth step, The cylindrical part, the tapered part, and the end face are subjected to straightening to complete the process.

Next, embodiments for each step will be described. FIG. 2 is a view showing an embodiment of the second step. 2
a-stage, chamfer taper angle 1 for press fitting of the short pipe
Plastic deformation is performed on both sides of the hoop material 1A with a predetermined width by plate-like dies 2a11 and 2a12 each having a tapered surface corresponding to a taper of 5 ° to 20 °, and a surplus portion of the plastic deformation portion is short-formed by a 2b stage. At the both ends of the feed length in the radial direction, the unwidth-determined portions 2b2 and 2c2, which are 3 to 5 times the plate thickness, and a cutout die 2b21 having a width equal to the entire length of the short pipe and a surplus portion of the plastic deformation portion cut out. , 2b22, and in the 2c stage, a cutting die 2c31, 2c34 is used to cut a short pipe at a radially installed length 2c1 to obtain a blank 2A.

If the fractured surface is larger than the shear plane in the cut of 2c1 of the charged length, if the gap of the butt portion when the cylindrical body is welded is large, the shrinkage becomes large, so that the fractured surface is as small as possible. Need to be smaller. Accordingly, a pad was used to restrict the material from moving at the cutting edge portion of the mold, and the clearance of the mold was set to 2% or less of the plate thickness.

FIG. 3 shows an embodiment in which, as described in the second step, both width portions of the hoop material are plastically formed to form a blank 2A, and then formed into a cylindrical body by bending, welding, and finishing. In the third bending process, as described above, there must be no gap in the butted portion and no V-grooves open outward. Therefore, the preliminary bend stages 3-1 at both ends of the blank 2A are used to form the cylindrical body. An unformed portion 3a1 having a thickness of about 3 to 5 times the plate thickness from the end is provided on the abutting surface at the time of bending to prevent distortion due to the difference in the inner and outer diameters of the bending curvature of the bend type. Preliminary bending was performed avoiding the locations, then intermediate bending was performed at the intermediate bending forming stage 3-2, and further, the cylindrical body 3a was formed at the cylindrical body forming stage 3-3.

In a fourth step, the butted portion 3a2 of the cylindrical body 3a is laser-welded. In this step, the relative positional accuracy between the welded part and the laser torch 4a1 is set to 10% or less of the plate thickness. As a countermeasure, as a countermeasure, the unwidth-determined portions 2b2 and 2c2 provided on the blank 2A in the second step come to both ends of the butted portion 3a2 when the direction perpendicular to the tapered surface is bent and formed into a cylindrical body. The jig 4a3 clamped both end surfaces of the width determining portions 2b2 and 2c2, and the cylindrical portion was clamped and positioned by the jig 4a2 to eliminate the gap between the welded portions. The clamped state is shown in 4a3a.

In the fifth and sixth steps, spatters and burrs generated by laser welding of the outer and inner peripheral surfaces are removed, or the boundary between the bead portion and the base material portion is removed by sandpaper foils 5a1 and 6a1. Polished finish. The method of setting the cylindrical bodies 4a and 5a in the polishing and finishing step is the same as the method of clamping in the fourth step, and the cylindrical parts are jigs 5a2 and 6a.
2, and the unwidth-determined portions 2b2, 2c2 were simultaneously clamped by positioning jigs 5a3, 6a3 provided on both sides.

In a seventh step, the non-width determining portions 2b2, 2c2
Is press-cut and removed. The non-width determining portion 2b2,
The cut of 2c2 is a notch cut portion 2 for determining the width in the second step.
It is desirable to cut in a straight line with the shear plane of b1,
For this purpose, a portion 7a2a for guiding the inner diameter of the cylindrical body 6a
Surface 7a2b which abuts against the end face of cylindrical body 6a
The cutting blade 7a2c of the cutting die 7a2 was provided on the same surface, and the punch 7a1 was provided corresponding to the cutting die 7a2.

In the finishing of the bead portion in the fifth step,
Since the unwidth-determined portion is tapered, it is difficult to completely remove it by finishing with the sandpaper foil 5a1. Therefore, the protrusion of the bead portion has the tapered side surface of the cutting punch 7a1 of the unwidth-determined portion. A tapered straightening surface 7a1a corresponding to the angle is provided, and a punch 7a1
Descends to cut the unwidth-determined portion, and further descends to correct the tapered surface with the taper correcting front face 7a1a of the punch. The above-mentioned die 7a2 and punch 7a1 were formed as a pair, were arranged on the left and right sides of the cylindrical body 6a, and pressed so as to sandwich the cylindrical body from the left and right sides, and then the unwidth-determined portion was press-cut.

In an eighth step, spatters and the like during the laser welding are removed, and in the correction processing in the next step, generation of scratches on the product due to entrapment of dust or foreign matter is prevented.

Whether or not the ninth step can be carried out is determined depending on the purpose of use of the product and the degree of required accuracy. For a part used as a product as shown in FIG. 4, a short tube is set in a molding die. When the filler is filled, it is not necessary for the filler to leak from the gap between the short tube and the mold, so it is necessary to further ensure the accuracy near the end face. Therefore, the cylindrical portion and the tapered portion of the chamfer are restrained and clamped by the upper die 9a1 and the lower die 9a2, and the left and right end surfaces and the inner end surface portion guide the inner diameter, the guide portion 9a3a and the forming surface 9a3b.
The mold 9a3, which is connected to the right side by the R-plane, was disposed to face left and right, and the end face was compression-corrected to secure a flat surface.

[0021]

As described above, forming short pipes having chamfered tapered surfaces at both ends from steel pipes depends on the type of processing in each processing step. According to a series of processing lines that connect each processing step of the invention and continuously manufacture from hoop material, reduction of intermediate yield loss, elimination of intermediate inventory, reduction of production equipment,
Space can be reduced, which is advantageous in terms of production efficiency and processing economy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a production line constituting the present invention.

FIG. 2 is an explanatory view of an embodiment of a press-in chamfering forming and blanking step.

FIG. 3 is an explanatory view of an embodiment of a cylindrical body forming and finishing step.

FIG. 4 is a diagram showing an application example of a manufactured part according to the present invention.

FIG. 5 is a shape diagram of a chamfer taper of a press-fitting part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Uncoiler 2 Plastic deformation process of chamfer taper surface 3 Bending forming process 4 Laser welding process 5, 6 Finishing process of bead part of outer diameter and inner diameter 7 Cutting process of undetermined width part 8 Cleaning process 9 Straightening process 2a Chamfering taper forming stage 2b Width cut stage 2c Blanking stage 1A Hoop material 2a1 Chamfered taper plastically deformed surface 2b1 Width cut portion 2b1a Uncut width inside cut surface 2c1 Cut portion 2b2, 2c2 Uncut width portion 2A Blank 3a to 9a Shape (cylindrical body) 3-1, 3-2, 3-3 Cylindrical body forming stage, preforming, bending, cylindrical forming 3a1 Non-forming range of pre-bend 3a2 Butt 4a1 Laser torch 5a1, 6a1 Finishing bead Sandpaper foil 7a1 and 7a2 Use punches, dies 7A1a, correcting faces 9a1,9a2,9a3 upper die of the tapered portion, the lower mold, the end surface correcting die 50a, 50b outer collar, an inner collar (short pipe) 50a1 and 50a2 outer diameter, the inner diameter of the chamfered tapered

Claims (4)

[Claims] In a manufacturing method, a plate material having a predetermined size is formed into a cylindrical body having both ends open and a butt portion is welded to form a short pipe, either the upper surface or the lower surface of the width of the hoop material. Plastically deforms the tapered surface corresponding to the chamfer for press-fitting, and cuts the excess part of the plastic deformation part, leaving the unwidth-determined parts at both ends of the radial length of the short pipe, and cuts the length further. Cut into a blank to form a blank, bending the blank in the direction perpendicular to the tapered surface to form a cylindrical body, determine the position of the welded portion across the unwidth-determined portions at both ends of the butted portion,
A manufacturing method characterized in that said welded portion is welded by a laser welding machine to form a short tube open at both ends. 2. The step of bending the cylindrical body includes a preliminary bend stage. The preliminary bend stage preliminarily forms the unbent portions at both ends in the lengthwise direction of the feed, and then performs a preform bending stage. 2. The method for producing a short pipe according to claim 1, wherein the pipe is formed by bending at a next stage. 3. The cutting punch for removing the unwidth-determined portion has a taper surface for correcting the tapered surface of the plastic deformation. After cutting the unwidth-determined portion on the taper surface, the punch further descends and welds. 2. The method according to claim 1, wherein the chamfered tapered surface of the portion is corrected. 4. The method according to claim 1, wherein the hoop material is formed so that a rolling direction thereof coincides with a circumferential direction of the short pipe.