JP2760087B2 - Cutting method of cylindrical work - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a cylindrical work typified by a road wheel rim, and more particularly, to a cylindrical shape obtained by coiling and welding a steel plate having an irregular cross section. The present invention relates to a method for performing a cutting process on a welded portion of a work.

2. Description of the Related Art In a method of manufacturing a road wheel rim made of a steel plate,
As shown in FIG. 4, a rectangular steel plate is used as the material P,
Through the steps of coiling → welding (flash butt or DC butt welding) → trimmer processing → side cut processing, a cylindrical work W, which is the rough shape of the road wheel rim, is created. (For example, "Automotive Engineering Book 19, Manufacturing Method of Automobiles", (Showa 55.4.20), Sankaido, P156).

The above trimmer processing can be performed by flash butt welding or
The purpose of this is to remove the weld bead from the weld generated by DC butt welding.
Both sides of Wz are processed and restrained by a pair of upper and lower clampers 51, 52, and the longitudinal direction of the welded part Wz is sent to the rough cutting tools 53, 53 and the finishing tools 54, 54, which are placed on the upper and lower sides of the welded part Wz. The cutting is performed by giving f.

Further, in the side cut processing, even if the above-described trimmer processing is performed, the weld bead portions are still formed on both end surfaces of the welded portion Wz.
Therefore, the flash F is cut and removed.

By the way, in order to reduce the weight of the road wheel rim while maintaining the strength, a rolled steel plate having an irregular cross section may be used instead of the above general steel plate. As shown in FIGS. 6 and 7, the deformed cross-section steel plate Pa has a central portion in the plate width direction locally thinned from one side thereof. At the same time the thickness of the can contribute to the improvement of the rim rigidity to ensure relatively large, it can reduce the center drop portion C _D near the plate thickness t of about 20%, even attained is 5-10% weight reduction as a whole That has been confirmed.

Here, the reference thickness T _o of the modified cross-section steel Pa of FIG. 6 2.0
When the ～5.0Mm, gradually decreasing the thickness toward the center, leaving a thick portion E of 1.1～1.3T _o the both ends in the thickness direction (l = 20~50mm), the thin portion Q among the most thick small minimum thickness portion Pc set to be 0.7~0.8T _o.

Problems to be Solved by the Invention FIG. 8 (A)
As shown in (B), when welding is performed after coiling is performed with the thin portion Q on the outer peripheral surface side, both ends of the welded portion Wz are deformed in the direction of arrow a due to thermal distortion. 8 (B), 8 (C), and 8 (D), a hatched portion indicated by a symbol Be indicates a weld bead portion generated by flash butt welding or DC butt welding.

Then, as shown in FIGS. 5 and 8 (C) and (D), both sides of the welded portion Wz are processed and restrained by the clampers 51 and 52, and then the rough cutting tools 53 and 53 and the finishing tools 54 and 54 are formed.
When cutting is performed, the longitudinal center portion of the welded portion Wz bulges outward due to the restraining force of the clampers 51 and 52, so that the front and back surfaces of the welded portion Wz are cut in parallel to each other. As shown in FIG. 8 (E), an uncut portion Fe occurs on the peripheral surface side. As a result, when the restraining force by the clampers 51 and 52 is released after the end of the trimmer processing, the uncut portion Fe of the weld bead portion Be protrudes inward due to the restoring force of the weld portion Wz as shown in FIG. Become.

When the work W having such uncut portion Fe is supplied to the roll forming in the next step, the road wheel rim cannot be formed into a perfect circle, and the runout accuracy deteriorates.

Therefore, before the roll forming, the above-described trimmer processing for removing the uncut portion Fe must be performed again, resulting in an increase in the number of steps.

The present invention has been made in view of the above-described problems, and it is possible to reliably cut and remove a weld bead portion of a weld portion in a single operation while being a cylindrical work made of a deformed cross-section steel plate. It is intended to provide an improved method.

Means for Solving the Problems The present invention relates to a cylindrical workpiece formed by coiling a rectangular deformed steel sheet having a thinned central portion in the sheet width direction as a raw material and welding both ends of the steel plate by butt welding. This is a method of performing cutting processing on the welded part, where both sides of the welded part are restrained with a pair of clampers on the front and back, and the roughed cutting tool placed opposite to the front and back sides across the welded part A step of rough-cutting by giving a feed in the longitudinal direction, and locally processing a portion corresponding to the thin-walled portion of the welded portion roughly cut under a pressure-constrained state by the clamper from one surface side to form a welded portion. Finishing cutting by a finishing tool which is disposed on the opposite side to the machining direction and follows the rough cutting tool.

Here, it is more preferable that the intermediate cutting tool is cut immediately after cutting with the rough cutting tool, and the finish cutting is performed with a finishing tool that follows the medium cutting tool.

Operation According to the above-described method, the portion corresponding to the thin portion is pressed from one surface side after the rough cutting, so that the uncut portion of the weld bead portion projects to the surface opposite to the processing direction. Then, all the weld bead portions are cut and removed by a single operation by the finishing bit cutting the uncut portion.

Embodiment FIG. 1 is a view showing an embodiment of the present invention, showing an example in which the present invention is applied to a method of manufacturing a road wheel rim R in the same manner as in the conventional case. I have.

As shown in FIG. 1, a pair of medium cutting tools 1,1 are provided after the rough cutting tools 53,53 in place of the conventional finishing tools 54,54.
In addition, a finishing tool 2 and a pressure roller 3 as a pressing means are arranged opposite to the middle cutting tools 1 and 1 in the cutting direction. The finishing tool 2 and the processing roller 3 are fixedly supported on a common slide (not shown) together with the rough cutting tools 53 and 53 and the medium cutting tools 1 and 1. The pressure roller 3 is supported by a spring or a hydraulic cylinder via a holder 4. A downward pressure is applied.

As shown in FIG. 2 (A), as shown in FIG. 2 (A), both sides of the welded portion Wz of the work W are clamped by the clampers 51 and 51 shown in FIG.
After being constrained by pressure at 2,52, cutting tools in the direction of the arrow f are given to the cutting tools 53, 53 and 1, 2. When the cutting feed is given, the preceding rough cutting tools 53, 53 as shown in FIG.
Cuts the weld bead Be on both the front and back sides of the welded part Wz, and furthermore, the medium cutting tool 1,1, which follows the rough cutting tool 53,53,
Weld bead B that could not be completely cut by rough cutting tool 53,53
e is removed by cutting.

At this time, the material Pa itself at the welded portion Wz (FIG. 2 (A)
(Except for the weld bead Be)) is the clamper 5
Recess Q ₁ due to thinning for pressurization binding of 1, 52 is curved so as to appear on the back side (inner circumference side of the workpiece W), hence the medium as shown in FIG. 2 (B) Although the front and back surfaces of the welded portion Wz after being cut by the cutting bits 1 and 1 are parallel to each other, an uncut portion Fe of the weld bead Be is generated at the center of the back surface of the welded portion Wz.

Further, as shown in FIG.
Before finishing the cutting by machining, the machining roller 3 and the finishing tool 2 that follow up the medium cutting tools 1 and 1 are welded Wz
Is cut from above and below, and the uncut portion Fe left uncut by the middle cutting bits 1 and 1 is cut by the finishing bit 2.

At this time, the pressure roller 3 causes the welding portion Wz
The lower part of the work W, which is pressurized and restrained by the clampers 51 and 52, is brought into close contact with the lower clamper 51. With the rolling of No. 3, the uncut portion Fe left on the back surface of the welded portion Wz bulges out, and this uncut portion is removed.
The finishing tool 2 that moves the Fe synchronously with the pressure roller 3 is scraped off.

As a result, the weld bead Be on both the front and back surfaces of the welded portion Wz is completely removed by a single cutting process, and the pressurized restraining force of the clampers 51 and 52 is released, thereby forming the welded portion Wz in FIG. 2 (C). Then, the original deformed sectional shape is restored as shown in FIG.

The burrs F remaining on both end surfaces of the welded portion Wz are cut and removed by a side cut process in a later step as described in FIG.

FIG. 3 shows another embodiment of the present invention. In this embodiment, instead of the pressure roller 3 of FIG. 1, a pressure means using a hydraulic cylinder 5 as a drive source is provided in an upper clamper 12. The movable clamper 6 is vertically movable.

That is, as shown in FIGS. 3 (A) and 3 (B), the intermediate cutting tool 1, 1 does not operate the movable clamper 6 until the middle cutting tool 1, 1 finishes cutting the portion corresponding to the thin portion Q of the welded portion Wz. The movable clamper 6 is caused to function as a part of the clamper 12, and the movable clamper 6 is moved down immediately before the finishing bite 2 starts cutting the portion corresponding to the thin portion Q.
As shown in FIG. 3C, the thin portion Q is pushed down to be elastically deformed. As a result, as shown in FIG.
Fe swells downward and finish bite 2 as in the previous embodiment.
Is removed by cutting.

Here, the present invention can also be applied to the cutting of a workpiece made of a general uniform-section steel sheet that is not a deformed-section steel sheet, and in that case, the thickness variation is absorbed by applying a local pressing force. Therefore, there is an advantage that the cutting removal efficiency of the weld bead portion is improved.

Advantageous Effects of the Invention As described above, according to the present invention, a portion corresponding to a thin-walled portion of a rough-cut welded portion is pressurized from one side, and is located on the opposite side to the above-described pressing direction with the welded portion interposed therebetween. The finish bit is followed by a finishing bit that follows the rough cutting bit, so that the weld bead can be cut and removed over the entire area of the weld width in a single cutting process. Processing becomes unnecessary, and man-hours can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory view of the configuration of a cutting apparatus to which the method of the present invention is applied, FIGS. 2 (A), (B) and (C) are explanatory views of steps showing a first embodiment of the present invention, and FIG. (A), (B),
(C) and (D) are process explanatory views showing another embodiment of the present invention, FIG. 4 is a process explanatory view showing a conventional method for manufacturing a road wheel rim, and FIG. 5 is used for conventional cutting. FIG. 6 is a cross-sectional view of a deformed steel sheet,
FIG. 7 is a cross-sectional view of a road wheel rim using a deformed steel sheet, and FIGS. 8 (A), (B), (C), (D), and FIG.
(E), (F) is a process explanatory view of a cutting method by the processing apparatus of FIG. 1: Medium cutting tool, 2: Finishing tool, 3: Pressure roller, 5: Hydraulic cylinder, 6, Movable clamper, 12, 51, 52
… Clamper, 53… Rough cutting tool, Be… Weld bead,
Fe: uncut portion, Pa: deformed section steel plate (material), Q: thin portion, W: work, Wz: weld.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23D 1/20 B23K 37/08 B23K 11/04

Claims (1)

(57) [Claims] 1. A cylindrical workpiece formed by coiling a rectangular shaped steel sheet having a deformed rectangular cross section having a thinned central portion in a width direction of the sheet and welding both ends of the steel sheet with abutting ends thereof, cutting the welded portion. In this method, both sides of the weld are pressurized and restrained by paired clampers on the front and back, and the longitudinal feed of the weld is given to the roughing cutting tool placed on both sides of the weld with the weld interposed. A step of rough-cutting, a portion corresponding to the thin-walled portion of the welded portion rough-cut under the pressure restrained state by the clamper is locally processed from one side, and the processing direction is sandwiched between the welded portions. And a step of performing a finish cutting by a finishing tool arranged on the opposite side to follow the rough cutting tool.