JP2016074021A - Hot three-dimensional bending device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a 3DQ device which can manufacture a bent component which satisfies an extremely high dimensional accuracy, for example, within a range of ±0.5 mm, even if a cross-sectional shape of the component is a flat shape and a strength thereof in a height direction is small.SOLUTION: A 3DQ device 10 is equipped with: a feeding mechanism 4 for a square tube 2; a support mechanism 3 for positioning the square tube 2; a coil 5 for heating the square tube 2 to Acpoint or higher; a busbar 6 which so supports the coil 5 as to be suspended and supplies a high-frequency power to the coil 5; a water-cooling apparatus 7 which injects cooling water onto an outer periphery of the heated square tube 2; and a holding mechanism or a gripping mechanism 8. The holding mechanism or the gripping mechanism 8 and the support mechanism 3 give a bending moment to a high temperature part 2a of the square tube 2, and further, the water-cooling apparatus 7 is fixedly located so that the water-cooling apparatus is not displaced downwards from a prescribed position during utilization thereof.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a hot three-dimensional bending apparatus.

  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, while feeding a hollow workpiece 2 having a closed cross section (in the following description, a steel pipe is taken as an example) by a support roll 3 fixedly arranged at a predetermined position, a feeding device 4 Is sent in the axial direction of the steel pipe 2 (the direction indicated by the arrow in FIG. 1). On the downstream side in the feed direction of the steel pipe 2 from the support roll 3 (hereinafter, also simply referred to as “downstream side”, and the opposite positional relationship is also simply referred to as “upstream side”), an annular high frequency heating the steel pipe 2 from the surroundings. An induction heating coil 5 (hereinafter also simply referred to as “coil”) is disposed. High-frequency power is supplied to the coil 5 from a bus bar (feeder) 6 that suspends and supports the coil 5, and the steel pipe 2 to be fed is heated to Ac ₃ points or more. Cooling water is sprayed to the outer periphery of the heated steel pipe 2 from the annular water cooling device 7 disposed on the downstream side in the feed direction of the coil 5 to quench the steel pipe 2.

  And, in the high temperature part 2a of the steel pipe 2 formed in the region from being heated by the coil 5 until being cooled by the water cooling device 7, sandwiching means or gripping means 8 disposed downstream of the water cooling device 7 The bending member 9 is manufactured by performing a hot bending process on the steel pipe 2 by applying a bending moment continuously or intermittently with the support roll 3.

  In addition, in order to raise the dimensional accuracy of the bending member 9, it is desirable for the length of the high temperature part 2a to be short in the range which can be bent. For this reason, 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, and this is advantageous in terms of space saving, but the water-cooling device 7 and the coil 5 do not need to be integrated.

  By the way, products manufactured by performing hot three-dimensional bending with the 3DQ apparatus 1 are mainly automobile members (for example, suspension arms), and the product requires a strict dimensional accuracy of ± 0.5 mm as an example. It is done.

  In paragraph 0004 of Patent Document 2, since it is inevitable that a slight bend (warp) exists in the steel pipe 2 to be sent out, when the steel pipe 2 coming out of the support roll 3 passes through the inside of the coil 5, the steel pipe 2. The gap between the outer circumference of the coil 5 and the inner circumference of the coil 5 becomes uneven in the circumferential direction, and a bending process occurs due to a temperature difference in the steel pipe 1 between a portion where the distance from the inner circumference of the coil 5 is near and a portion where this distance is far. It is described that there is a possibility that the processing accuracy of the material may be lowered.

  As a countermeasure, Patent Document 2 describes that a movable frame having a coil fixed thereon is float-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 are provided on the movable frame. Has been. As a result, the coil can be centered together with the movable frame in accordance with the bending (warping) of the steel pipe, and the gap between the outer circumference of the steel pipe and the inner circumference of the coil can be made uniform, so that the steel pipe can be heated uniformly in the circumferential direction. Yes.

JP 2008-23573 A JP 2012-55963 A

  The direction in which the bus bar 6 for hanging and supporting the coil 5 is extended and installed when the bending member manufactured by the 3DQ apparatus has a low-strength portion in its cross-sectional shape as a result of extensive studies by the inventors. And the direction in which the strength of the bending member is low (for example, the direction in which the short side extends when the cross-sectional shape of the bending member is rectangular) matches, the bending member has a very high dimensional accuracy of, for example, ± 0.5 mm. It has been found that a bending member having a desired dimensional accuracy cannot be manufactured even when the bending apparatus disclosed in Patent Document 2 is used.

  An object of the present invention is to provide a direction in which a bus bar for suspending and supporting a coil extends and a direction in which the strength of the bending member is low when the bending member manufactured by the 3DQ apparatus has a low strength portion in its cross-sectional shape. (For example, when the cross-sectional shape of the bending member is rectangular, the bending member that satisfies the extremely high dimensional accuracy of, for example, ± 0.5 mm) is manufactured even when it coincides with the direction in which the short side extends. It is to provide a 3DQ device capable of

  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) In order to investigate which of the eccentricity of the coil 5 and the eccentricity of the water cooling device 7 is affected by the decrease in the dimensional accuracy of the bending member 9, the water cooling device 7 and the coil 5 are not integrated. As a component, only the water cooling device 7 was eccentric with respect to the square tube 2 without decentering the coil 5.

  FIG. 3A shows the degree of reduction in dimensional accuracy in the height direction when the coil 5 and the water cooling device 7 are both eccentric in the square tube 7 having a flat cross section, as well as the water cooling device 7. FIG. 3B is an explanatory diagram showing the cross-sectional dimensions of the square tube 2. FIG. 3B is a graph showing the degree of decrease in dimensional accuracy in the height direction when only the eccentricity is made.

  As shown in FIGS. 3 (a) and 3 (b), the degree of decrease in the dimensional accuracy of the bending member 9 when only the water cooling device 7 is eccentric is surprisingly different between the coil 5 and the water cooling device 7. Also, the degree of dimensional accuracy of the bending member 9 when the eccentric member was eccentric was almost the same as that of the bending member 9.

  From this, it is not the eccentricity of the coil with respect to the rectangular tube 2 but the eccentricity of the water cooling device 7 with respect to the rectangular tube 2 that mainly affects the decrease in the dimensional accuracy of the bending member 9. It turned out to be.

The present invention is listed below.
(1) a feed mechanism for feeding a hollow workpiece having a flat 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 which is disposed at a predetermined position downstream of the support mechanism and heats the workpiece to Ac ₃ points or more;
A bus bar for supporting the high-frequency induction heating coil such that its extending direction substantially coincides with a direction in which the strength of the workpiece is low, and supplying power to the high-frequency induction heating coil;
A water-cooling device that is disposed at a predetermined position downstream of the high-frequency induction heating coil with respect to the feed direction of the workpiece, and that injects cooling water to the outer periphery of the workpiece;
A three-dimensionally arranged downstream of the water-cooling device, and a holding mechanism for holding the workpiece movably or a holding mechanism for holding and holding the workpiece.
The clamping mechanism or the gripping mechanism and the support mechanism give a bending moment to a high temperature part of the workpiece formed in a region from being heated by the high frequency induction heating coil to being cooled by the water cooling device. And then
The 3DQ device is characterized in that the water cooling device is fixedly installed so as not to be displaced downward from the predetermined position during operation.

  (2) The 3DQ device according to (1), wherein the bus bar suspends and supports the high-frequency induction heating coil.

  (3) The 3DQ device according to (1) or (2), wherein the water cooling device is fixedly installed so that a positional relationship with the support mechanism does not change.

  (4) The 3DQ device according to any one of items (1) to (3), wherein the water cooling device is integrated with the high-frequency induction heating coil.

  According to the present invention, it becomes possible to manufacture a hollow bending member having a flat closed cross section that satisfies extremely high dimensional accuracy of, for example, ± 0.5 mm, particularly an automobile member (for example, a suspension arm).

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 (a) shows the degree of reduction in dimensional accuracy in the height direction when both the coil and the water cooling device are eccentric in a square tube having a flat cross section, and only the water cooling device is eccentric. FIG. 3B is an explanatory diagram showing a cross-sectional dimension of a square tube. FIG. 4 is an explanatory view showing an installation form of the water cooling device in the 3DQ device, FIG. 4 (a) shows a case where the coil and the water cooling device are connected and configured integrally, and FIG. 4 (b) shows the coil. And the case where the water cooling device is installed independently without being integrated.

  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, a 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 bus bar 6, a water cooling device 7, and a clamping mechanism or a gripping mechanism 8. 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 the Ac3 point or higher. As the coil 5, a well-known and commonly used coil of this type can be used.

[Bus bar 6]
The bus bar 6 suspends and supports the coil 5 so that the coil 5 is disposed at the predetermined position. The bus bar 6 is made of a conductor (for example, made of copper) that can withstand high voltage and high current, and is configured in a plate shape to securely hold the coil 5 and the water cooling device 7. The bus bar 6 has a predetermined surface area so that the current density does not exceed a specified value.

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

[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 the Ac3 point or more 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 that suspends and supports the coil 5 expands due to 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 the dimensional accuracy of the bending member 9 manufactured with the 3DQ apparatus 10 falls by eccentricity of the water cooling apparatus 7 with respect to the square tube 2. FIG.

  Therefore, in the 3DQ device 10, the water cooling device 7 is fixedly installed so as not to be displaced downward from a predetermined position during operation. Thereby, the water cooling device 7 is fixedly installed so that the positional relationship with the support mechanism 3 does not change.

  FIG. 4 is an explanatory view showing an installation form of the water cooling device 7 in the 3DQ device 10, and FIG. 4 (a) shows a case where the coil 5 and the water cooling device 7 are connected and configured integrally, and FIG. b) shows the case where the coil 5 and the water-cooling device 7 are installed independently without being integrated.

  As described above, the means for fixing and installing the water cooling device 7 so as not to be displaced downward from a predetermined position when the 3DQ device is in operation is not particularly limited. For example, when the coil 5 and the water cooling device 7 are configured integrally as shown in FIG. 4A, it is exemplified that at least one of the coil 5 or the water cooling device 7 is mounted on the fixed base 11. In addition, as shown in FIG. 4B, when the water cooling device 7 is not integrated with the coil 5 and is a separate part, the water cooling device 7 is mounted on the fixed base 11.

  By using the fixed base 11, the eccentricity of the water cooling device 7 with respect to the square tube 2 due to the downward displacement of the water cooling device 7 can be prevented, so that the dimensional accuracy of the bending member 9 can be prevented from being lowered.

  In FIG. 4A, FIG. 4A shows a case where the coil 5 and the water cooling device 7 are connected and configured integrally, but unlike this, the water cooling device 7 is built in the coil 5. Needless to say, they may be integrally formed.

2 Square tube 2a High temperature part 3 Support mechanism 4 Feed mechanism 5 High frequency induction heating coil 6 Bus bar 7 Water cooling device 8 Nipping mechanism or gripping mechanism 9 Bending member 10 3DQ device of the present invention

Claims (4)

A feed mechanism for feeding a hollow workpiece having a flat 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 which is disposed at a predetermined position downstream of the support mechanism and heats the workpiece to Ac ₃ points or more;
A bus bar for supporting the high-frequency induction heating coil such that its extending direction substantially coincides with a direction in which the strength of the workpiece is low, and supplying power to the high-frequency induction heating coil;
A water-cooling device that is disposed at a predetermined position downstream of the high-frequency induction heating coil with respect to the feed direction of the workpiece, and that injects cooling water to the outer periphery of the workpiece;
A three-dimensionally arranged downstream of the water-cooling device, and a holding mechanism for holding the workpiece movably or a holding mechanism for holding and holding the workpiece.
The clamping mechanism or the gripping mechanism and the support mechanism give a bending moment to a high temperature part of the workpiece formed in a region from being heated by the high frequency induction heating coil to being cooled by the water cooling device. And then
The hot three-dimensional bending apparatus, wherein the water cooling device is fixedly installed so as not to be displaced downward from the predetermined position during operation.   The hot three-dimensional bending apparatus according to claim 1, wherein the bus bar suspends and supports the high-frequency induction heating coil.   The hot three-dimensional bending apparatus according to claim 1 or 2, wherein the water cooling device is fixedly installed so that a positional relationship with the support mechanism does not change.   The hot three-dimensional bending apparatus according to any one of claims 1 to 3, wherein the water cooling device is integrated with the high-frequency induction heating coil.

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