JPH0215292B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to small radius bending (2DR or less) processing of Al-Mg aluminum alloy tubes, and particularly to suppressing thinning and flattening that occur during bending plastic processing. This invention relates to an aluminum tube small radius bending bender suitable for

[Background of the invention]

Although small radius bending (2DR or less) of piping is generally carried out, there are no specific regulations regarding wall thickness reduction and flatness. He was celebrating.
Small radius bending of Al-Mg aluminum alloy pipes is very difficult, and the thickness reduction rate and flatness rate of these bender-bent parts are calculated based on JIS straight pipe dimensions and flatness tolerance (thickness reduction rate). : 12.5%, flatness ratio: 5
%) There are no vendor devices that should be controlled within this range. In addition, related devices of this type include, for example, Utility Model Publication No. 57-14966 and Japanese Patent Publication No. 58-2726.
For example, the number etc.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-radius bending bender for pipes that can suppress the thinning rate and flattening rate of the tube side surface, which occur during small-radius bending of a pipe to be processed, to within specified values.

[Summary of the invention]

The present invention provides a general-purpose bender having a bending device that performs hot compression by providing a compression bending device that performs compression bending, a side bending device that presses the back side of the tube to increase pressure in rapid feed, and a heating device. Equipped with a side pressure bending function, the thinning and flattening that occur during small radius bending (2DR or less) of Al-Mg aluminum alloy pipes, etc., can be corrected by reducing the thinning and flattening of JIS straight pipe dimensions ( Thickness reduction rate: 12.5%, flattening rate: 5%).

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. Reference numeral 1 denotes an aluminum tube as a workpiece, which is usually bent into the shape shown in FIG. When the aluminum tube 1 is thinned and flattened during bending, as shown in FIG. 5, the plate thickness tends to increase on the ventral side, and the plate thickness tends to decrease on the back side as it is bent and stretched. In Figures 1 to 3, 1 is an aluminum pipe;
2 is a bender frame of a general-purpose bender body; 3 is a bending die for tightening and fixing one end of the aluminum tube 1 with a bending clamp 4 to perform the bending process; and 5 is a bending die on the side of the aluminum tube 1 facing the bending die 3. 6 is a compression mold for tightening the aluminum tube 1 and performing compression bending; 7 is a wiper mold provided adjacent to the tension bending mold 3; 8 is a tension chain. 8a is a draw-bending cylinder that drives the draw-bending mold 3; 9 is a compression-bending cylinder that drives the compression mold 6; 10 is a side speed-up cylinder that drives the side mold 5; 11 is the inside of the side mold 5 and the wiper mold 7. Heating control device 1
This is a heater whose heating temperature is adjusted in step 2.

In the above-described configuration, the aluminum tube 1 is heated approximately by the heater 11 before the bending process of the aluminum tube 1 is started.
Heat to 250℃, draw and bend mold 3 and compression mold 6
At the same time, the side die 5 facing the draw bending die 3 is operated to perform side bending. in this case,
The compression bending load by the compression die 6 is made to be about 10% overload compared to the pull bending load by the draw bending die 3, and the thickness is increased by making it about 5% over the draw bending speed, and the side bending speed by the side die 5 is increased by about 5%. By making the bending speed approximately 10% higher than the compression bending speed, it is possible to suppress thinning on the back side and suppress thinning and flattening of the aluminum tube 1 during small radius bending.
In other words, the thickness is increased by hot compression, and the back surface where the thickness decreases the most is locally increased by side speed-up bending.
By shifting the neutral axis in the figure from the ventral side to the back side of the aluminum tube 1 using the combined force of compressive load and side acceleration, the thinning rate and flattening rate during small radius bending of the aluminum tube can be reduced by approximately 12.5%. Within,
It can be suppressed to within about 5%. Although this embodiment has been described using an aluminum tube (Al--Mg aluminum alloy tube) as the workpiece, the present invention is not limited to this. That is, it can be applied not only to materials that are difficult to bend, such as special pipes such as titanium and stainless steel pipes, but also to various types of pipes.

〔Effect of the invention〕

According to the present invention, small radius bending (2DR or less) of Al-Mg aluminum alloy tubes etc. with poor bending workability is possible.
By adding a compression bending device, a side bending device, and a heating device to the draw bending device of a general-purpose bender, it is possible to perform hot compression side pressure bending, which reduces the reduction that occurs during bending of aluminum pipes. Fleshness and flatness can be suppressed within specified values.

[Brief explanation of drawings]

FIG. 1 is a plan view of a small radius bending bender for a pipe to be processed showing an embodiment of the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a plan view showing a part of FIG. 1 in cross section. FIG. 4 is an explanatory diagram showing a three-stage bending state of the aluminum tube, and FIG. 5 is a cross-sectional view taken along the line AA in FIG. 4. 1...Aluminum pipe, 2...Bender frame, 3...Draw bending type, 4...Bending clamp, 5...Side type, 6...
Compression type, 7... Wiper type, 8... Draw bending cylinder,
8a... tension chain, 9... compression bending cylinder,
10...Side speed increasing cylinder, 11...Heater, 1
2...Heating control device.

Claims (1)

[Claims] 1. A stretching and bending device that fixes one end of the tube to be processed and applies a tensile load to perform the bending process, and a compression bending device that performs compression bending by controlling and applying a compressive load to the other end of the tube to be processed. , a side bending device that presses the side surface of the pipe to be processed facing the drawing bending device to control the bending speed and perform side bending;
A small round radius of a pipe, characterized in that it is composed of a wiper mold on the side of the drawing and bending device and a heating device for heating the pipe to be processed, which is provided in the side mold of the side bending device.
bending bender.