JPH02235523A - Bending machine for tube stock - Google Patents

Abstract

PURPOSE:To form a tube stock without deforming its tip part by arranging a clamping mandrel capable of advancing or separating to or from the tube tip engaging with a clamping die on the side of the clamping die and advancing the clamping mandrel in bending the tube stock to insert the tube tip between the clamping mandrel and the clamping die. CONSTITUTION:While a slide die 3 and the clamping die 4 move back upwards, the tube stocck T1 is fit on the tip part of the mandrel 2 and set to advance a slide 3 and the clamping die 4. Thereafter, a hydraulic cylinder 51 is operated, the clamping mandrel 5 is advanced, its tip part is advanced into the inside of the tip part of the tube stock T1 engaging with the clamping die 4, and the tip part is held by a bending die 1, the clamping die 4 and the clamping mandrel 5. As this state is kept, the bending die 1 with the clamping die 4 is driven and rotated by a prescribed angle. The tube stock T1 is bent as it is adhered closely with the bending die 1. In this way, a tube stock having a short straight part can be formed easily from a short stock without generating wrinkle and deforming the tip part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pipe bending apparatus using a rotary bending method, and particularly to an apparatus suitable for bending short pipes with a small bending radius.

[Conventional technology]

2. Description of the Related Art As one type of pipe bending apparatus, a four-turn bending type processing apparatus called "draw bending" is known.

This device inserts a mandrel inside the pipe material, places the tip of the mandrel at the position where the pipe material begins to bend, and in this state, the bending die is driven and rotated together with the clamping die to perform the bending process. In this case, since the bending start part of the pipe is held in a substantially circular shape by the mandrel, the bending part is prevented from becoming flattened after processing, and the generation of wrinkles on the inner peripheral side of the bending part is also suppressed. However, if you use a short tube with a short straight section and try to bend the tube to a diameter that is less than one time the outer diameter of the tube, slippage may occur between the tube and the clamping die, causing the tube to bend. Since the tube cannot be pressed sufficiently against the bending die, there are problems in that wrinkles occur, flattening occurs, and the tube end becomes deformed.

In order to prevent this, it may be possible to increase the length that engages with the clamping type pipe material, but this would lengthen the straight pipe section for bending, requiring extra material and extra post-processing. However, there is a problem in that it is necessary and leads to an increase in costs.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention has been made for the purpose of providing an improved bending device that can easily form a short pipe material with a straight section. It is.

[Means for Solving the Problems] The device according to the present invention has a tightening mandrel that can move forward and backward toward the end of the tube that engages with the tightening die, and is arranged on the side of the tightening die. The present invention is characterized in that the tightening mandrel is moved forward to position its tip within the tube end, so that the tube end can be held between the tightening mandrel and the tightening die.

[Embodiments] Hereinafter, embodiments of the apparatus according to the present invention will be described with reference to the drawings.

As shown in Fig. 1, the main components of the rotary bending type bending device are a bending die 1, a mandrel 2 that advances and retreats toward the bending die 1 from the tangential direction of the die, and a mandrel 2 that moves in the direction perpendicular to the axis of the bending die 1. A sliding die 3 that moves forward and backward from the bending die 1 toward the bending die 1 and is movable in the axial direction of the mandrel 2; It consists of a tightening mold 4 that can be rotated as a
In the present invention, a tightening mandrel 5 is attached to an arm 4l that holds the tightening die 4 via an auxiliary arm 42.

The tightening mandrel 5 is attached to the auxiliary arm 42 so that its axis coincides with the axis of the opposing mandrel 2 in the state shown in FIG. 1 when the tightening die 4 advances toward the bending die 1. It can move forward and backward a predetermined distance by operating a fixed hydraulic cylinder 51. The tightening mandrel 5 is also retracted as shown in FIG. 3 before processing starts, and the tube material TI is set in the processing device, and the tightening die 4 is moved toward the bending die 1 following the slide die 3. After moving forward,
As shown in FIG. 1, it advances and enters the end of the set tube material TI and stops, the bending process is completed, and before the clamping die 4 retreats, it retreats and returns.

In this example, the tip of the tightening mandrel 5 is a pipe material T.
The outer diameter is slightly smaller than the inner diameter of T1, which is because this part initially has a small diameter, but after being inserted into the end of the pipe material, the diameter is enlarged so that it can come into contact with the inner surface of the end part of the pipe material T1. There is no problem even if it is an expansion type like this. The length of penetration into the tube end is preferably such that the tip reaches near the opposite side of the clamping die.

A device with such a configuration. To bend a pipe material, first, in the state in which the slide mold 3 and clamping mold 4 are retracted upward as shown in Fig. 1 (at this time, the clamping mandrel 5 is also retracted), they are moved forward. The tube material T1 is fitted and set on the tip of the mandrel 2, and the slide mold 3 and the tightening mold 4 are
After moving forward as shown in Fig. 1, the hydraulic cylinder 5l
is actuated to advance the tightening mandrel 5, and its tip is advanced into the end of the tube material Tl that engages with the tightening die 4, and the end of the tube material Tl is bent between the bending die 1, the tightening die 4, and the tightening die 4. It is held between the mandrels 5 (Fig. 1).

Then, in this state, by rotating the bending die 1 together with the clamping die 4 at a predetermined angle, the pipe material TI is pulled and bent while being in close contact with the bending die 1 (Fig. 2).
.

When the bending die 1 and the tightening die 4 are rotated at a predetermined angle to complete the bending process, first, as shown in FIG. 3, the hydraulic cylinder 51 is operated to move the tightening mandrel 5 back and forth. After that, move back the tightening die 4, and continue to move the slide die 3.
Retract and return. After that, when the hydraulic cylinder 61 is activated to move the work wiper 6 forward and the hydraulic cylinder 2l is activated to move the mandrel 2 backward, the machined pipe material T2 is unrestrained, so the pipe material T2
is pushed by the workpiece collar 62 and separated from the bending die 1. After this, when the bending die 1, the tightening die 4, and the work swirler 6 are returned to their respective positions, and the mandrel 2 is moved forward and returned to its original position, the entire apparatus is returned to its original position. The next bending process is performed by operating each part in sequence.

During the bending process using this device, the outside of the bent portion of the tube material Tl is subjected to tensile force, but since a part of the end of the tube material TI is held between the clamping die 4 and the clamping mandrel 5,
There is no slippage between the tube material T1 and the clamping die 4, and therefore, even if the tube material TI is made of a short length, there will be no wrinkles or deformation of the end, and the tube material TI will not wrinkle or deform at the end, and the tube material TI will not wrinkle or deform at the end. It is bent.

[Effects of the Invention] As is clear from the above explanation, the processing device of the present invention has a clamping mandrel arranged on the clamping mold side to work together with the clamping mold, so it is possible to use a short material. It has the advantage of being able to easily form a short straight tube without wrinkles or end deformation even when processed with a small bending radius, and its practical value is extremely high.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the state before the start of bending in one embodiment of the processing device according to the present invention, FIG. 2 is an explanatory diagram showing the state of deafness at the end of bending by the device, and FIG. FIG. 2 is an explanatory diagram showing the state of the device before recovery. 1: Bending mold, 2: Mandrel, 4: 5: 6: 21. 51 and 61: 41: 42: TI and T2: Slide type, tightening type, tightening mandrel, work sorrel, work stopper, hydraulic cylinder, arm, capture arm, pipe material. 1st mouth A 3rd mouth 2nd mouth

Claims (1)

[Claims] 1. Place the tip of the mandrel at the position where the pipe material begins to bend,
In a pipe bending device that performs bending by driving and rotating a bending die together with a clamping die in this state, a clamping mandrel that can move forward and backward toward the pipe end that engages with the clamping die is provided on the clamping die side. is arranged, and when bending the pipe material, the tightening mandrel is moved forward to position its tip within the pipe end, and the pipe end is held between the tightening mandrel and the clamping die. A pipe material bending device characterized by: