JP2016074020A - Hot three-dimensional bending device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot three-dimensional bending device which can suppress lowering of a dimensional accuracy of a bent component due to uneven heating with a simple device configuration.SOLUTION: A 3DQ device 10 is equipped with: a feeding mechanism 4 for feeding a square tube 2 in a longitudinal direction; a support mechanism 3 for positioning the square tube 2; a high frequency induction heating coil 5 for heating the square tube 2; a busbar 6-1 which so supports the high frequency induction heating coil 5 as to be suspended and supplies an electric power to the high frequency induction heating coil; a water-cooling apparatus 7 which injects cooling water onto an outer periphery of the square tube 2. The busbar 6-1 has a substantially L-shaped outer shape comprising a first portion 12 which is extended in a substantially vertical direction, and a second portion 13 which is connected to the first portion 12 and is extended in a substantially horizontal direction.SELECTED DRAWING: Figure 3

Description

  Patent Document 1 discloses a hot three-dimensional bending apparatus 1 (hereinafter referred to as “3DQ apparatus”) whose outline is shown in FIG. Hereinafter, the 3DQ device 1 will be described.

As shown in FIG. 1, a hollow work piece 2 having a closed cross section (in the following description, taking a steel pipe as an example) is positioned by support rolls 3 and 3 fixedly arranged at predetermined positions. Send in the axial direction. On the downstream side in the feed direction of the steel pipe 2 relative to the support rolls 3 and 3 (hereinafter, also simply referred to as “downstream side” and the opposite positional relationship is also simply referred to as “upstream side”), the steel pipe 2 is heated from the surroundings. An annular high frequency induction heating coil 5 (hereinafter also simply referred to as “coil”) is disposed. Electric power is supplied to the coil 5 from the bus bar 6 that suspends and supports the coil 5, and the steel pipe 2 to be fed is heated to Ac ₁ point or more. Cooling water is sprayed from the annular water cooling device 7 arranged on the downstream side in the feed direction of the coil 5 to the entire outer surface of the heated steel pipe 1 to quench the steel pipe 1.

  And it is arrange | positioned at the high temperature part of the steel pipe 2 currently formed in the area | region after being heated with the coil 5 until it cools with the water cooling apparatus 7 so that it can move to the downstream rather than the water cooling apparatus 7 in two dimensions or three dimensions. The product 9 (bending member) is manufactured by applying a bending moment continuously or intermittently by the movable roller die 8 and the supporting rolls 3 and 3 and hot bending the steel pipe 1.

  In addition, in order to raise a processing precision, the one where the length of the axial direction of a high temperature part is short in the range which can be bent is effective. Therefore, the water cooling device 7 is disposed in the immediate vicinity of the coil 5. In many cases, the water-cooling device 7 and the coil 5 are connected to be integrated, which is advantageous in terms of space saving.

  By the way, the product 9 manufactured by hot bending with the 3DQ apparatus 1 is mainly a member for automobiles, and the product is required to have a strict dimensional accuracy of ± 0.5 mm as an example.

  In paragraph 0004 of Patent Document 2, in the 3DQ device 1, it is inevitable that there is a slight bend (warp) of the steel pipe 2 that is sent out, so that the steel pipe 2 that comes out of the bending fulcrum member passes through the inside of the coil 5. When this occurs, the gap between the outer circumference of the steel pipe 2 and the inner circumference of the coil 5 becomes non-uniform, and the temperature of the steel pipe 2 is different between the part where the distance from the inner circumference of the coil 5 is near and the part far away from the coil 5 and is bent. It has been pointed out that the processing accuracy of processing may decrease. As a countermeasure against this, in Patent Document 2, a movable frame on which the coil 5 is fixed is floatingly supported on the fixed frame via a floating support means, and a plurality of guide members that contact the outer peripheral surface of the steel pipe 2 are provided on the movable frame. Thereby, a coil is centered with a movable frame according to the bending (warp) of the steel pipe 2, and the clearance gap between the outer periphery of the steel pipe 2 and the inner periphery of a coil can be equalized, and the steel pipe 2 can be heated uniformly in the circumferential direction. It is said.

JP 2008-23573 A JP 2012-55963 A

  As disclosed in Patent Document 2, heating that should be uniform in the circumferential direction of the steel pipe 2 by the coil 5 becomes non-uniform (hereinafter, in this specification, such non-uniform heating in the circumferential direction is referred to as “biased heating”. "), The bending accuracy decreases. In this regard, the invention disclosed in Patent Document 2 is certainly effective in preventing uneven heating.

However, in the present invention, the configuration of the apparatus is complicated. Since the 3DQ apparatus 1 heats the steel pipe 2 to a high temperature of Ac ₁ point or more, if the structure of the apparatus is complicated, a failure factor increases and the reliability of the apparatus cannot be denied.

  Further, according to the investigation by the present inventors, even if the steel pipe 2 has some bending (warping), the influence on the processing accuracy of the product is small. This is presumably because the degree of partial heating due to bending (warping) is small because the steel pipe 2 is positioned by the support mechanism (support roll) on the upstream side of the coil 5.

  As a result of extensive studies by the inventors, the bending member manufactured by the 3DQ apparatus has a flat cross-sectional shape with a small strength in the height direction and an extremely high value of, for example, ± 0.5 mm. In the case of a component that requires dimensional accuracy, it has been found that a bending member having a desired dimensional accuracy cannot be manufactured even if the bending apparatus disclosed in Patent Document 2 is used.

  An object of the present invention is to provide a hot three-dimensional bending apparatus that can suppress a decrease in dimensional accuracy of a bending member due to partial heating with a simple apparatus configuration. Specifically, the bending member has a high cross-sectional shape. An object of the present invention is to provide a 3DQ apparatus capable of producing a bending member having a flat shape with small strength in the vertical direction and satisfying extremely high dimensional accuracy of, for example, ± 0.5 mm.

  The inventors examined the 3DQ device 1 in detail. In this examination, it is assumed that the workpiece 2 by the 3DQ apparatus 1 is a hollow square tube having a flat closed cross section. As a result of this examination, the following new findings A and B were obtained, and the present invention was completed.

  (A) When the 3DQ device 1 is in operation, heat generated by the coil 5 expands the bus bar 6 that supplies high-frequency power to the coil 5 and supports the coil 5 in a suspended manner. The expansion of the bus bar 6 causes the coil 5 fixed to the lower part of the bus bar 6 and the water cooling device 7 integrated with the coil 5 to be displaced downward from the original installation position, so that the coil 5 and the water cooling device 7 are It is eccentric with respect to the square tube 2.

  FIG. 2A is a graph showing the amount of displacement of the coil 5 when the coil 5 is suspended and supported by the bus bar 6 having a vertical length of 600 mm and the heating of the coil 5 is turned on and off. ) Is an explanatory view showing the vicinity of the coil 5 and the bus bar 6.

  As shown in FIGS. 2A and 2B, when the heating of the coil 5 is turned ON, the bus bar 6 is thermally expanded, and thereby the coil 5 is displaced downward by about 0.5 mm from the position before the heating. For this reason, the coil 5 and the water cooling device 7 are eccentric with respect to the square tube 2.

When this eccentricity occurs, the dimensional accuracy of the product (bending member) 9 is significantly reduced.
(B) By devising the shape of the bus bar 6, specifically by making it an L-shaped outer shape, the vertical expansion of the bus bar 6 can be released upward. Thereby, the displacement of the coil 5 due to the expansion of the bus bar 6 is reduced, and uneven heating is suppressed. As a result, a decrease in dimensional accuracy of the bending member can be suppressed.

The present invention is listed below.
(1) a feed mechanism for feeding a hollow workpiece having a closed cross section in the longitudinal direction;
A support mechanism that positions the workpiece by being fixedly arranged at a predetermined position downstream of the feed mechanism in the feed direction of the workpiece;
A high-frequency induction heating coil that is arranged at a predetermined arrangement position downstream of the support mechanism and heats the workpiece;
A bus bar for supporting the high frequency induction heating coil in a suspended manner and supplying electric power to the high frequency induction heating coil;
A water cooling device that is arranged at a predetermined arrangement position downstream of the high-frequency induction heating coil in the feed direction of the workpiece, and that injects cooling water to the outer periphery of the workpiece;
The bus bar has a substantially L-shaped outer shape including a first portion extending substantially in the vertical direction and a second portion connected to the first portion and extending in the substantially horizontal direction. Hot three-dimensional bending machine characterized by

  According to the present invention, it is possible to provide a hot three-dimensional bending apparatus capable of suppressing a decrease in the dimensional accuracy of a bending member due to partial heating with a simple apparatus configuration. Specifically, the bending member has a sectional shape in the height direction. It is possible to provide a 3DQ apparatus capable of manufacturing a bending member that has a flat shape with a low strength and satisfies extremely high dimensional accuracy of, for example, ± 0.5 mm.

FIG. 1 is an explanatory diagram showing an outline of a hot three-dimensional bending apparatus. 2A is a graph showing the amount of displacement of the coil when the coil is suspended and supported by a bus bar having a vertical length of 600 mm, and the coil is turned on and off. FIG. 2B is a graph showing the coil and bus bar. It is explanatory drawing which extracts and shows the vicinity. FIG. 3 is an explanatory view showing a bus bar.

  The present invention will be described with reference to the accompanying drawings. In brief, since the difference between the 3DQ device 10 according to the present invention with respect to the 3DQ device 1 shown in FIG. 1 is the installation mode of the water cooling device 7, the following description will be made with reference to FIG.

  As shown in FIG. 1, the 3DQ device 10 according to the present invention includes a feed mechanism 4, a support mechanism 3, a high frequency induction heating coil 5, a water cooling device 7, a clamping mechanism or gripping mechanism 8, and a bus bar 6-1. And have.

  The 3DQ apparatus 10 performs a hot three-dimensional bending process on the hollow workpiece 2 having a flat closed cross section to produce a hollow bending member 9 having a flat closed cross section. Examples of the cross-sectional shape of the workpiece 2 include a rectangle, an ellipse, and an oval. In the following description, a case where the workpiece 2 is a hollow and square steel tube 2 having a rectangular cross-sectional shape is taken as an example.

[Feeding mechanism 4]
The feed mechanism 4 only needs to be able to feed the square tube 2 in its longitudinal direction, and is not limited to a specific feed mechanism. As the feed mechanism, a well-known and conventional one can be used as this type of feed mechanism, and specifically, one using a ball screw, one using a transport roller, and the like are exemplified. Further, an industrial robot may be used as the feed mechanism 4.

[Support mechanism 3]
The support mechanism 3 is fixedly disposed at a predetermined position downstream of the feed mechanism 4 in the feed direction of the square tube 2. The support mechanism 3 sends the square tube 2 in its longitudinal direction while positioning. As the support mechanism 3, a well-known and conventional one can be used as this type of support mechanism. Specifically, a pair of drive rolls that come into contact with the outer surface of the square tube 4 is exemplified. In the example shown in FIG. 1, a pair of drive rolls 3 are arranged in two sets of tandem.

[Coil 5]
The high frequency induction heating coil 5 is disposed at a predetermined position downstream of the support mechanism 3. The coil 5 is disposed surrounding the square tube 2 at a predetermined distance from the periphery of the square tube 2. The coil 5 generates a high-frequency magnetic field and supplies high-frequency energy to the square tube 2 to heat the square tube 2 to Ac ₁ point or more. As the coil 5, a well-known and commonly used coil of this type can be used.

[Water cooling device 7]
The water cooling device 7 is disposed at a predetermined position downstream of the coil 5 in the feeding direction of the square tube 2. As described above, it is advantageous for increasing the bending accuracy that the length in the axial direction of the high temperature portion 2a formed in the square tube 2 is as short as possible. For this reason, the water cooling device 7 is installed close to the coil 5. Therefore, it is desirable to provide the water cooling device 7 integrally with the coil 5, but it may be separated from the coil 5 as a separate part. The water cooling device 7 rapidly cools and quenches the square tube 2 heated to _one or more points Ac by the coil 5 by injecting cooling water to the entire circumference of the square tube 2.

[Holding mechanism or gripping mechanism 8]
The clamping mechanism or gripping mechanism 8 is arranged on the downstream side of the water cooling device 7 so as to be movable in three dimensions. The sandwiching mechanism 8 is a mechanism that sandwiches the square tube 2 movably, and is exemplified by a pair of drive rolls that come into contact with the outer surface of the square tube 2. On the other hand, the gripping mechanism 8 grips the square tube 2 by being fixedly attached to the inner surface or the outer surface of the square tube 2. For example, a chuck mechanism fixedly disposed inside the square tube 2 is exemplified. Is done.

  In the 3DQ device 10, either the clamping mechanism or the gripping mechanism 8 can be used, and may be selected as appropriate according to the situation. In order to dispose the holding mechanism or gripping mechanism 8 in a three-dimensional manner, it is easy to hold the holding mechanism or the gripping mechanism 8 with an industrial robot.

  The pinching mechanism or gripping mechanism 8 and the support mechanism 3 impart a bending moment to the high temperature portion 2a of the square tube 2 formed in the region from being heated by the coil 5 until being cooled by the water cooling device 7. Thereby, the hollow bending member 9 which has a rectangular closed cross section is manufactured.

  As described above, when the 3DQ device 10 is in operation, the bus bar 6-1 that suspends and supports the coil 5 is expanded by the heat generated by the coil 5. When the water cooling device 7 is configured integrally with the coil 5 due to the expansion of the bus bar 6, the coil 5 fixed to the lower portion of the bus bar 6 and the water cooling device 7 integrated with the coil 5 are initially positioned. Displaces mainly from the bottom. For this reason, the coil 5 and the water cooling device 7 are eccentric with respect to the square tube 2. And eccentric heating of the water cooling device 7 with respect to the square tube 2 results in eccentric heating, and the dimensional accuracy of the bending member 9 manufactured by the 3DQ device 10 decreases.

  Thus, in the 3DQ device 10, the shape of the bus bar 6 is devised so that the coil 5 and the water cooling device 7 due to expansion are not displaced downward from a predetermined position during operation.

[Bus bar 6-1]
FIG. 3 is an explanatory diagram showing the bus bar 6-1.

  The bus bar 6-1 suspends and supports the coil 5 so that the coil 5 is disposed at a predetermined position. Moreover, the bus bar 6-1 is made of a conductor (for example, made of copper) that can withstand high voltage and high current, and has rigidity capable of reliably holding the coil 5 and the water cooling device 7.

  The upper part of the bus bar 6-1 is fixed to a high-frequency power source (not shown) arranged on the upper part of the bus bar 6-1. For this reason, the bus bar 6-1 tends to be displaced mainly downward when thermally expanded.

  As shown in FIG. 3, the bus bar 6-1 includes a first portion 12 extending in a substantially vertical direction, and a second portion 13 connected to the first portion 12 and extending in a substantially horizontal direction. It has a substantially L-shaped outer shape. Thereby, the thermal expansion in the vertical direction can be released upward.

  According to the 3DQ apparatus 10 according to the present invention, it is possible to suppress a decrease in dimensional accuracy of the bending member 9 due to partial heating with a simple apparatus configuration using the bus bar 6-1 having a substantially L-shaped outer shape.

2 square tube 2a high temperature part 3 support mechanism 4 feed mechanism 5 high frequency induction heating coil 6, 6-1 bus bar 7 water cooling device 8 clamping mechanism or gripping mechanism 9 bending member 10 3DQ device according to the present invention

Claims (1)

A feed mechanism for feeding a hollow workpiece having a closed cross section in the longitudinal direction;
A support mechanism that positions the workpiece by being fixedly arranged at a predetermined position downstream of the feed mechanism in the feed direction of the workpiece;
A high-frequency induction heating coil that is arranged at a predetermined arrangement position downstream of the support mechanism and heats the workpiece;
A bus bar for supporting the high frequency induction heating coil in a suspended manner and supplying electric power to the high frequency induction heating coil;
A water cooling device that is arranged at a predetermined arrangement position downstream of the high-frequency induction heating coil in the feed direction of the workpiece, and that injects cooling water to the outer periphery of the workpiece;
The bus bar has a substantially L-shaped outer shape including a first portion extending substantially in the vertical direction and a second portion connected to the first portion and extending in the substantially horizontal direction. Hot three-dimensional bending machine characterized by

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