JP2021016891A - Manufacturing method of hollow bent component, manufacturing device of hollow bent component, and hollow bent component - Google Patents

Abstract

To provide a manufacturing method and a manufacturing device of a hollow bent component, in which a product width can be modified at each position in a longer direction according to various design needs, without requiring additional welding processes or the like, and to provide a hollow bent component.SOLUTION: A manufacturing method of a hollow bent component includes the steps of: supporting a hollow stock Pm at a first position A; partially heating the hollow stock Pm at a portion to be heated using a heating device 12 disposed at a second position B; cooling the hollow stock Pm using a cooling device 13 disposed at a third position C; and applying shearing force to the portion to be heated by moving the support position of the hollow stock Pm at a fourth position D in a two-dimensional direction or a three-dimensional direction. In the manufacturing method of the hollow bent component, a width dimension of a shearing bending portion in the hollow stock Pm can be changed, by setting an inclination angle α of the heating device 12 and the cooling device 13 relative to the feeding direction, in accordance with a shearing angle θ of the hollow stock Pm formed before and after applying the shearing force.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for manufacturing a hollow bent part, an apparatus for manufacturing a hollow bent part, and a hollow bent part.

As is well known, a metal strength member, a reinforcing member or a structural member having a hollow bent shape used in automobiles, various machines and the like is required to be lightweight and have high strength. Conventionally, this type of hollow bent part has been manufactured by, for example, cold bending, welding of stamped products, punching of thick plates, and forging. However, there are limits to the weight reduction and high strength of hollow bent parts manufactured by these manufacturing methods, and it has not been easy to realize them.

In recent years, for example, as disclosed in Non-Patent Document 1, production of this type of hollow bent part by a so-called tube hydroforming method has also been actively studied. However, in particular, since the tube hydroforming method is cold forming, there is a limit to the forming of high-strength materials. As described on page 28 of Non-Patent Document 1, the tube hydroforming method has problems such as development of a material as a material and expansion of the degree of freedom of formable shape, and further development in the future. is required.

In view of such a situation, the present inventors have previously disclosed an invention relating to a bending apparatus according to Patent Document 1. FIG. 8 is an explanatory diagram schematically showing an outline of the bending apparatus 100.
As shown in FIG. 8, in this bending apparatus 100, a steel pipe (hereinafter, hollow material Pm) movably supported in the axial direction by a pair of supporting means 101 and 101 is indicated by an arrow from the upstream side to the downstream side. While feeding in the F direction by a feeding device (not shown), bending is performed at a downstream position of the supporting means 101, 101 to manufacture a hollow bent part Pp made of steel. That is, the hollow material Pm is rapidly heated to a temperature range in which the hollow material Pm can be partially hardened by the high-frequency heating coil 102 at the downstream position of the support means 101 and 101, and the hollow material is rapidly heated by the water cooling device 103 arranged downstream of the high-frequency heating coil 102. Quench Pm. Then, the position of the movable roller die 104 having at least one set of roll pairs 104a and 104a to be fed while supporting the hollow material Pm is changed in the three-dimensional direction (in some cases, the two-dimensional direction), and the heated portion of the hollow material Pm is changed. The hollow material Pm is bent by applying a bending moment to the hollow material Pm. According to this bending apparatus 100, it becomes possible to manufacture a hollow bending part Pp having high strength with high working efficiency.

International Publication No. 2006/093006 International Publication No. 2011/024741

Automotive Technology Vol. 57, No. 6, 2003 pp. 23-28

Hollow bending parts used in automobiles, various machines, and the like have various shapes. Among them, there are many hollow bent parts having an extremely small bent portion in which the bending radius of the bent portion is, for example, 1 to 2 times or less than the diameter of the metal pipe (the length of the side in the bending direction in the case of a rectangular cross section). Exists.
However, according to the method of Patent Document 1, bending is performed so that the bending radius is, for example, 1 to 2 times or less than the diameter of the metal tube (the length of the side in the bending direction in the case of a rectangular cross section). If this happens, there is a risk that wrinkles or folds will occur on the inner peripheral side of the bent portion, or that the plate thickness on the outer peripheral side of the bent portion will be significantly reduced and breakage will occur. Therefore, it has been difficult to manufacture a hollow bent part having a small bent portion.

Therefore, in order to solve these problems, the present inventors have disclosed an invention relating to a shear bending apparatus according to Patent Document 2.
As shown in FIG. 9, the shear bending apparatus 200 includes a first support means 201, a heating means 202, a cooling means 203, and a gripping means 204. The first support means 201 supports the hollow metal material Pm at the first position A while relatively feeding it in the longitudinal direction thereof. The heating means 202 partially heats the hollow material Pm at a second position B downstream of the first position A along the feeding direction of the hollow material Pm. The cooling means 203 cools (forced cooling or natural cooling) the heated portion of the hollow material Pm at the third position C downstream of the second position B along the feeding direction of the hollow material Pm. The gripping means 204 moves the hollow material Pm in a two-dimensional direction or a three-dimensional direction while positioning the hollow material Pm at a third position D downstream of the second position C along the feeding direction of the hollow material Pm. Shear force is applied to the heated portion of the hollow material Pm.

According to this shear bending apparatus 200, it is possible to apply shearing and heat treatment to the heated portion of the hollow material Pm. Then, according to this shear bending apparatus 200, a height having a bent portion having a bending radius of 1 to 2 times or less than the diameter of the metal pipe (the length of the side in the bending direction in the case of a rectangular cross section). It is possible to reliably mass-produce strong hollow bent parts at low cost.
Therefore, according to the manufacturing method described in Patent Document 2, it is possible to manufacture hollow bent parts having high strength and a small bending radius, and it is possible to significantly reduce the weight of many mechanical parts such as automobiles. became.

On the other hand, when designing an integrated hollow bent part as a mechanical part, there is a part where it is necessary to partially increase the product width in order to secure the strength and rigidity required for the design. On the contrary, when the assembled parts interfere with other parts, there are some parts where it is necessary to partially reduce the product width. In response to these various demands, there is no integral molding technology that changes the product width of high-strength materials, and there is no choice but to reinforce by additional welding after molding the product. It is undeniable that such an additional welding process is complicated.

The present invention has been made in view of the above circumstances, and is a method for manufacturing a hollow bent part capable of changing the product width at each position in the longitudinal direction according to various design needs without requiring an additional welding process or the like. The purpose is to provide. Another object of the present invention is to provide an apparatus for manufacturing a hollow bent part for carrying out the method for manufacturing the hollow bent part. Another object of the present invention is to provide a hollow bent part manufactured by a method for manufacturing these hollow bent parts and a manufacturing apparatus.

In order to solve the above problems and achieve the above object, the present invention employs the following aspects.
[1] In one aspect of the present invention, a long hollow metal material is supported at a first position while being fed in a feeding direction along the longitudinal direction thereof, and the first position is supported along the feeding direction. The hollow material is partially heated in the heated portion by a heating means arranged at a second position downstream of the second position, and arranged at a third position downstream of the second position along the feeding direction. The hollow material is cooled by the cooling means, and the hollow material is supported at a fourth position downstream of the third position along the feed direction, and the support position is set in the two-dimensional direction or the three-dimensional direction. A method for manufacturing a hollow bent part, which applies a shearing force to the heated portion of the hollow material by moving the hollow material, depending on the shear angle formed before and after applying the shearing force of the hollow material. By setting the inclination angles of the heating means and the cooling means with respect to the feeding direction, the width dimension of the shear-bent portion in the hollow material is changed.

[2] In the embodiment of the above [1], when the setting is made, the shear angle is θ (degrees), the inclination angle is α (degrees), and the original width dimension of the hollow material is W ₀ (mm). ), The width dimension of the shear-bent portion may be W (mm), and the shear angle and the inclination angle may be set so as to satisfy the following equation (1).

[3] Another aspect of the present invention is a support device that supports a long hollow metal material at a first position while feeding it in a feeding direction along its longitudinal direction, and said that the hollow material is supported along the feeding direction. A heating means that is arranged at a second position downstream of the first position and partially heats the hollow material in the heated portion, and a third position downstream of the second position along the feed direction. The hollow material is supported at a cooling means for cooling the hollow material and a fourth position downstream of the third position along the feed direction, and the support position is set in the two-dimensional direction or. Depending on the shearing force applying means that applies a shearing force to the heated portion of the hollow material by moving in the three-dimensional direction, and the shearing angle formed before and after applying the shearing force of the hollow material. By setting the inclination angles of the heating means and the cooling means with respect to the feeding direction and controlling the heating means, the cooling means, and the shearing force applying means based on the settings, shear bending processing in the hollow material is performed. An apparatus for manufacturing hollow bent parts, comprising a control means for changing the width dimension of a portion.

[4] In the embodiment of the above [3], the following configuration may be adopted: when the control means makes the setting, the shear angle is set to θ (degree) and the inclination angle is set to α (degree). The original width dimension of the hollow material is W ₀ (mm), the width dimension of the shear bending portion is W (mm), and the shear angle and the inclination angle are satisfied so as to satisfy the following equation (2). To set.

[5] Yet another aspect of the present invention is an elongated hollow integral part made of metal, wherein the width of the heat-treated bent portion is adjacent to the bent portion when viewed along the longitudinal direction thereof. It is a hollow bent part that is different from the width of the part.

[6] In the embodiment of [5] above, the following configuration may be adopted: the cross-sectional shape perpendicular to the longitudinal direction has a circular or rectangular closed cross-sectional shape; the bent portion is the bent portion of the bent portion. It has a bending radius that is not more than twice the width, which is the dimension between the outer shape on the inner peripheral side and the outer shape on the outer peripheral side. Further, the bent portion may have a bending radius of 0.2 to 2 times the width.

[7] In the embodiment of [5] or [6] above, the following configuration may be adopted: it is made of steel and the amount of martensite at the bent portion is 50% or more.

According to the method and apparatus for manufacturing hollow bent parts according to the above aspect, the product width can be changed at each position in the longitudinal direction according to various design needs without requiring an additional welding step or the like. Further, according to the hollow bent part according to the above aspect, the product width is changed at each position in the longitudinal direction according to various design needs.

It is a vertical cross-sectional view which shows typically the manufacturing apparatus of the hollow bending part which concerns on one Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the hollow bending part using the manufacturing apparatus, and is the partially enlarged view in the X1 part of FIG. It is a figure for demonstrating the manufacturing method of the hollow bending part using this manufacturing apparatus, and is the cross-sectional view in line Y1-Y1 of FIG. It is a figure for demonstrating the principle of the effect by the manufacturing method using this manufacturing apparatus, and is the shear angle θ and the width ratio when the inclination angle α of a heating coil is changed in the range of 15 degrees to 120 degrees. It is a graph which shows the relationship of. (A) to (c) are diagrams showing the outer shape of the hollow bent part machined in the first embodiment. It is a figure which shows the outer shape of the hollow bending part machined in Example 2. It is a figure which shows the hollow bending part processed in the Example of this invention, and the hardened part is shown by hatching. It is explanatory drawing which shows the schematic structure of the bending processing apparatus disclosed in Patent Document 1. It is explanatory drawing which shows the schematic structure of the shear bending apparatus disclosed in Patent Document 2.

Hereinafter, a method and an apparatus for manufacturing a hollow bent part according to an embodiment of the present invention, and a hollow bent part manufactured by the same manufacturing method and the same manufacturing apparatus will be described with reference to the drawings. In the following description, the hollow bent part manufactured by the present invention is made of a hollow square tube made of steel and having a rectangular cross-sectional shape (hereinafter, hollow material Pm), and is used in automobiles and various machines. An example of manufacturing a product such as a strength part, a reinforcing part, or a structural part (hereinafter, hollow bending part Pp) will be described. First, a manufacturing apparatus for hollow bent parts to which this manufacturing method is applied (hereinafter, manufacturing apparatus 10) will be described first, and then the manufacturing method and further the hollow bent parts will be described.

[Manufacturing equipment for hollow bent parts]
FIG. 1 is an explanatory view schematically showing a manufacturing apparatus 10 for hollow bent parts according to the present embodiment.
With this manufacturing apparatus 10, the hollow material Pm is shear-bent to obtain a hollow bent part Pp. The hollow material Pm is a long square tube having a closed cross-sectional shape having a hollow rectangular cross section perpendicular to the longitudinal direction thereof. The processing target of the present embodiment is not limited to the square pipe, and can be applied to, for example, other steel pipes having a circular shape, an elliptical shape, and various irregular cross-sectional shapes. Further, as the hollow material Pm having a rectangular cross section, the cross-sectional shape thereof can be applied to either a square or a rectangular shape. Furthermore, a metal pipe other than the steel pipe may be used as the hollow material Pm.

As shown in FIG. 1, the manufacturing apparatus 10 includes a support device 11, a heating device 12, a cooling device 13, a shearing force applying device 14, and a control device 15.
(1) Support device 11
As shown by the arrow F in FIG. 1, in the support device 11, the hollow material Pm is fed in the longitudinal direction by a feeding device (not shown).
The type of the feeding device is exemplified by using an electric servo cylinder, but the type is not limited to a specific type, and a known type such as a type using a ball screw or a type using a timing belt or a chain can be adopted.

The hollow material Pm is fed by the feeding device at a predetermined feeding speed in the axial direction (toward the left hand side of the paper surface along the arrow F). The hollow material Pm is supported by the support device 11 at the first position A. That is, the support device 11 supports the hollow material Pm fed by the feed device in the axial direction at the first position A.

In this embodiment, a block is used as the support device 11. The block has a through hole 11a through which the hollow material Pm can be inserted with a gap. Although not shown, a block may be divided into a plurality of blocks, a hydraulic cylinder or an air cylinder may be connected, and a hollow material Pm may be sandwiched and supported. Further, the support device 11 is not limited to a specific type, and a known support device of this type can be adopted. For example, as another configuration, one set or two or more sets of hole-shaped rolls arranged so as to face each other can be used side by side.
The support device 11 is fixedly arranged on a mounting table (not shown). However, the present invention is not limited to this aspect, and the support device 11 may be supported by an end effector (not shown) of an industrial robot.
The hollow material Pm is further sent in the direction of arrow F after passing through the first position A in which the support device 11 is installed.

(2) Heating device 12
The heating device 12 is arranged at a second position B downstream of the first position A along the feeding direction of the hollow material Pm. The heating device 12 heats the entire circumference of the cross section of the hollow material Pm sent from the support device 11 in a part in the longitudinal direction. An induction heating device is used as the heating device 12. The induction heating device may be any known device as long as it has a coil capable of inducing and heating the hollow material Pm, for example, at a high frequency.
The heating coil 12a of the heating device 12 is arranged so as to surround the entire circumference of the cross section in a part of the hollow material Pm in the longitudinal direction at a predetermined distance from the outer surface of the hollow material Pm. Then, the hollow material Pm is partially rapidly heated by the heating device 12.

As the installation means (not shown) of the heating device 12, the heating coil 12a can be arranged at the second position B so that the inclination angle can be adjusted. That is, the installation means of the heating device 12 can incline the heating coil 12a at a set angle with respect to the feeding direction of the hollow material Pm. In the example of FIG. 1, the heating coils 12a are inclined so as to intersect the longitudinal direction of the hollow material Pm (the feeding direction of the hollow material Pm shown by the arrow F) at an inclination angle α in a side view. More specifically, as shown in FIG. 1, when viewed in a cross section including the center line of the heating coil 12a, the center position in the width direction in the cross section above the heating coil 12a and the cross section below the heating coil 12a. Let it be a straight line L1 connecting the center position in the width direction in. Then, the central axis of the hollow material Pm before reaching the heating coil 12a is a straight line L2. At this time, when the angle formed by the straight line L1 and the straight line L2 is the inclination angle α, the inclination arrangement of the heating coil 12a is changed by setting the inclination angle α to an acute angle of less than 90 ° or an obtuse angle of more than 90 °. can do. Further, the inclination angle α can be set to 90 ° (right angle).

As a means for installing the heating device 12, for example, an end effector of a well-known and commonly used industrial robot can be exemplified, but a known one can be adopted as long as the inclination angle α can be adjusted as specified. The adjustment of the inclination angle α by the installation means of the heating device 12 may be configured to be automatically controlled by the installation means receiving a control signal from the control device 15 provided in the manufacturing device 10. In this case, in the longitudinal direction of the hollow material Pm, the relationship between the position where the shear bending process is performed and the inclination angle α to be set at the same position is stored in advance in the control device 15, and the feed amount of the hollow material Pm is predetermined. As an example, it is conceivable to control the inclination angle α of the heating coil 12a when the feed amount reaches a predetermined angle.

Although not shown, one or more preheating devices (for example, a small high-frequency heating device) capable of preheating the hollow material Pm are arranged at an upstream position of the heating device 12 along the feeding direction of the hollow material Pm. The hollow material Pm can also be heated by using the preheating means in combination with the heating device 12. In this case, the hollow material Pm can be heated a plurality of times.

(3) Cooling device 13
The cooling device 13 is arranged at a third position C downstream of the second position B along the feeding direction of the hollow material Pm. The cooling device 13 rapidly cools the portion of the hollow material Pm heated at the second position B. When the hollow material Pm is cooled by the cooling device 13, the portion between the first portion heated by the heating device 12 and the second portion cooled by the cooling device 13 is at a high temperature. The deformation resistance is significantly reduced.

The cooling device 13 is not limited to a specific type of cooling device as long as it can obtain a desired cooling rate. In general, it is desirable to use a water cooling device that cools the hollow material Pm by injecting cooling water toward a predetermined position on the outer peripheral surface of the hollow material Pm. In the present embodiment, a large number of cooling water injection nozzles 13a are arranged on the immediately downstream side of the heating device 12 so as to surround a part of the cross section of the hollow material Pm in the longitudinal direction and away from the outer surface of the hollow material Pm. doing. Then, the cooling water from the cooling water injection nozzle 13a is injected toward the outer surface of the hollow material Pm.
It is desirable that the cooling water is sprayed diagonally in the direction in which the hollow material Pm is sent out so as not to hinder the heating of the hollow material Pm by the heating device 12. Further, if the distance between each cooling water injection nozzle 13a and the hollow material Pm is changed and set in the cross section orthogonal to the axial direction of the hollow material Pm, the area in the axial direction in which the hollow material Pm is cooled can be set. Can be adjusted.

The portion of the hollow material Pm heated by the heating device 12 is rapidly cooled by the cooling device 13.
By appropriately adjusting the start temperature and cooling rate of water cooling by the cooling device 13, it becomes possible to quench or anneal a part or all of the rapid cooling portion in the hollow material Pm. Thereby, for example, the strength of a part or all of the bent portion of the hollow material Pm can be significantly increased to, for example, 1500 MPa or more.

The means for installing the cooling device 13 may be any means as long as the cooling device 13 can be arranged at the third position C, and is not limited to a specific installation means. However, in order to manufacture the hollow bent part Pp having high dimensional accuracy by the manufacturing apparatus 10 of the present embodiment, heating is performed by setting the distance between the second position B and the third position C as short as possible. It is desirable to set the region between the first portion heated by the device 12 and the second portion cooled by the cooling device 13 as small as possible. For this purpose, it is desirable to arrange the cooling water injection nozzle 13a close to the high frequency heating coil 12a. Therefore, it is desirable to arrange the cooling water injection nozzle 13a at a position immediately after the induction heating coil 12a. Further, the cooling device 13 may be fixed to the installation means of the heating device 12. In this case, both the cooling water injection nozzle 13a and the heating coil 12a can be tilted at the same tilt angle α while maintaining the relative positional relationship between the cooling water injection nozzle 13a and the heating coil 12a.

However, the present invention is not limited to this configuration, and the cooling device 13 installation means may be provided separately from the heating device 12 installation means. As the installation means (not shown) of the cooling device 13, each cooling water injection nozzle 13a can be arranged at the third position C so that the inclination angle can be adjusted. That is, the installation means of the cooling device 13 can incline the cooling device 13 at a set angle with respect to the feeding direction of the hollow material Pm. For example, as shown in FIG. 1, each cooling water injection nozzle 13a is tilted so as to intersect with the longitudinal direction of the hollow material Pm (the feeding direction of the hollow material Pm shown by the arrow F) at an inclination angle α in a side view. Can be placed. Then, by synchronizing the inclination angle of each cooling water injection nozzle 13a with the inclination angle of the heating coil 12a and making it always the same, the cooling water injection nozzles 13a are arranged adjacent to each other without interfering with the heating coil 12a. Becomes possible.

As the means for installing the cooling device 13 in this case, for example, an end effector of a well-known and commonly used industrial robot can be exemplified, but a known one can be adopted as long as the inclination angle α can be adjusted as specified. .. The adjustment of the inclination angle α by the installation means of the cooling device 13 may be configured to be automatically controlled by receiving the control signal from the control device 15 by the installation means of the cooling device 13. In this case, as an example, it is conceivable to refer to the control signal sent from the control device 15 to the installation means of the heating device 12 and control so that the same inclination angle α can be synchronously inclined.

(4) Shear force applying device 14
The shearing force applying device 14 is arranged at a fourth position D downstream of the third position C along the feeding direction of the hollow material Pm. The shearing force applying device 14 moves in the two-dimensional direction or the three-dimensional direction while positioning the hollow material Pm. As a result, the shearing force applying device 14 applies a shearing force to the region of the hollow material Pm between the first portion heated by the heating device 12 and the second portion cooled by the cooling device 13. The hollow material Pm is shear-bent.

In the example shown in FIG. 1, a pair of upper and lower gripping means 14a and 14b are provided as the shearing force applying device 14. These gripping means 14a and 14b determine the support position of the hollow material Pm by contacting the outer surface of the hollow material Pm. Then, the shear angle θ shown in FIG. 1 can be adjusted by adjusting the support position. The shear angle θ is the feed direction of the hollow material Pm (more specifically, the direction along the straight line L2) on the virtual plane including the straight lines L1 and L2 described above, and the hollow material Pm after passing through the cooling device 13. The angle between the outer surface and the surface.

The pair of upper and lower gripping means 14a and 14b are held by a moving mechanism (also not shown) that is movable in a two-dimensional direction or a three-dimensional direction.
A support device (not shown) for supporting the hollow material Pm after passing through the shear force applying device 14 is further provided at a position downstream of the installation position of the shearing force applying device 14 along the feeding direction of the hollow material Pm. May be good. In this case, it becomes possible to manufacture a hollow bent part Pp having higher dimensional accuracy.

The cross section of the hollow material Pm in a part in the longitudinal direction is heated by the heating device 12, and the deformation resistance is significantly reduced. Therefore, by moving the positions of the pair of upper and lower gripping means 14a and 14b in the three-dimensional direction at the fourth position D downstream of the third position C along the feeding direction of the hollow material Pm, FIG. As shown in the above, the shear force Ws can be applied to the region of the hollow material Pm between the first portion heated by the heating device 12 and the second portion cooled by the cooling device 13.

A bent portion is formed by the action of the shearing force Ws on the hollow material Pm. In the present embodiment, a shearing force is applied to the heated portion of the hollow material Pm instead of applying a bending moment as in the invention disclosed in Patent Document 1. Therefore, the bending radius is extremely small, such as 0.2 to 2 times the width W (product width), which is the distance between the outer curve on the inner peripheral side and the outer curve on the outer peripheral side of the bent portion. A hollow bent part Pp having a portion can be manufactured.
In the manufacturing method using the control device 10 of the present embodiment, the processable range of the bending radius can be widened by appropriately setting the combination of the shear angle θ and the inclination angle α. Therefore, it is possible to process a large bending radius in which the bending radius exceeds twice. On the other hand, even when a small bending radius is required for product design reasons, it is possible to obtain an extremely small bending radius of 0.2 times or more and 2 times or less, which was difficult with the prior art.
The details of the width W and the bending radius referred to here will be described later in the description of the hollow bending component Pp.

The shearing force applying device 14 may be installed via a mechanism capable of movably arranging a pair of upper and lower gripping means 14a and 14b in a two-dimensional direction or a three-dimensional direction as described above. Such a mechanism does not require any particular limitation. For example, the gripping means 14a and 14b may be held by a well-known industrial robot end effector.

(5) Control device 15
The control device 15 (control means) controls various operations of the support device 11, the heating device 12, the cooling device 13, and the shearing force applying device 14 described above.
The control device 15 sets the inclination angle α of the heating device 12 and the cooling device 13 with respect to the feeding direction according to the shear angle θ formed before and after applying the shearing force along the feeding direction of the hollow material Pm. By controlling the heating device 12, the cooling device 13, and the shearing force applying device 14 based on the above settings, the width dimension W of the shear bending portion in the hollow material Pm is set to the original width dimension W ₀ of the hollow material Pm. Change to the same value or a different value. That is, the combination of the shear angle θ and the inclination angle α is set so that the width ratio W / W ₀ is more than 1, 1 or less than 1. When the width ratio W / W ₀ = 1 is set, the width dimension is maintained, and when the width ratio W / W ₀ > 1 is set, the product width is increased and the width ratio W / W ₀ <1 is set. In some cases, the product width is reduced.

[Manufacturing method of hollow bent parts]
Subsequently, a method of manufacturing the hollow bent component Pp from the hollow material Pm by using the manufacturing apparatus 10 will be described below. In this manufacturing method, by applying a shear bending process to the hollow material Pm, it is possible to partially change the width (hereinafter, product width) when viewed along the longitudinal direction thereof.
That is, according to the manufacturing method of the present embodiment, (1) the angle (shear angle θ) in the traveling direction between the feed direction of the hollow material Pm, which is the material, and the hollow bending part Pp, which is the product, and (2). By appropriately selecting the feed direction of the hollow material Pm, which is the material, and the angle between the heating device 12 (inclination angle α, which is the inclination of the heating coil 12a), the hollow bending component Pp after undergoing shear bending is performed. The product width of is changeable.

This point will be described below with reference to FIGS. 2 and 3. FIG. 2 is a diagram for explaining a method of manufacturing a hollow bent part Pp using the manufacturing apparatus 10, and is a partially enlarged view of a portion X1 of FIG. FIG. 3 is a view for explaining a method of manufacturing a hollow bent part Pp using the manufacturing apparatus 10, and is a cross-sectional view taken along the line Y1-Y1 of FIG.

Strictly speaking, the actual deformation during processing shown in FIG. 1 is not a pure shear deformation, but the dimensions of the hollow material Pm (external dimensions, plate thickness, etc.), the dimensions of the heating device 12 and the cooling device 13, and the shearing force. It may differ slightly depending on the structure of the imparting device 14. However, for the sake of explanation, an ideal and pure shear deformation is assumed here.

Hereinafter, a case where a hollow material Pm having a plate thickness t ₀ and a rectangular cross section of dimensions W ₀ × dimensions H ₀ is shear-bent in a two-dimensional direction along the width direction will be described as shown in FIG.

Here, the inclination angle of the heating coil 12a is α (degrees), and the shear angle of the hollow material Pm during shear bending is θ (degrees). Then, the hollow material Pm having a rectangular cross section of dimension W ₀ × dimension H ₀ is subjected to shear bending by the manufacturing apparatus 10 to obtain a hollow bent part Pp having a rectangular cross section of dimension W × dimension H. In this case, the width dimension of the bent portion that has undergone shear bending changes as shown in FIG.

Specifically, the following equation (3) can be obtained from the geometric shape shown in FIG. 2.

The lower equation (4) is obtained by modifying the upper equation (3), and the lower equation (5) is obtained by further modifying the lower equation (4).

FIG. 4 is a graph showing a tendency that W / W _0, which is a width ratio obtained by dividing the product width W by the raw pipe width W ₀ , increases or decreases depending on the combination of the shear angle θ and the inclination angle α based on the above equation (4). Is. The shear angle θ is changed in the range of 0 to 90 degrees, and the inclination angle α is changed in the range of 15 to 120 degrees (15 degrees, 20 degrees, 30 degrees, 45 degrees, 60 degrees, 90 degrees, 120 degrees). I let you. In the graph of FIG. 4, the line of "width ratio = 1.0" shows the original state (W = W ₀ ) without increasing or decreasing the product width. Then, at "width ratio>1.0" above this line, it is shown that the product width is increasing (W> W ₀ ). On the contrary, a "width ratio <1.0" below this line indicates that the product width is reduced (W <W ₀ ).

Therefore, by setting (or changing) the inclination angle α of the heating coil 12a according to the required shear angle θ, it is possible to obtain the width dimension W of the following three patterns.
(A) Partially increase the product width W (W / W ₀ > 1)
(B) Maintain the product width W as the raw pipe width (W / W ₀ = 1)
(C) Partially reduce the product width W (W / W ₀ <1)
That is, the target product width W is partially set, the above (a) or the above (c) is determined, and then an appropriate inclination angle α satisfying the above equation (5) is set with respect to the shear angle θ. Then, the product width can be changed. On the contrary, if the above (b) is determined and an appropriate inclination angle α satisfying the above equation (5) is set for the shear angle θ, the product width can be maintained as it is.

On the other hand, the product height, the product height H, remains the dimension H ₀ as shown in the following formula (6).

As described above, since each of the above equations assumes ideal pure shear deformation, the dimensions of the hollow material Pm (external dimensions, plate thickness, etc.), and the dimensions of the heating device 12 and the cooling device 13 are actually obtained. Or, it may change slightly depending on the structure of the shear force applying device 14. Therefore, at the stage of production preparation, the shear angle θ and the width ratio W / when the inclination angle α of the heating coil 12a is changed in advance using the actual hollow material Pm, the heating device 12, and the cooling device 13. It is desirable to find the relationship with W ₀ . By utilizing these prior data to actually produce the product, smoother production becomes possible.

After obtaining the relationship between the inclination angle α and the shear angle θ and the width ratio W / W ₀ that satisfy the above equation (4) by the above production preparation, the manufacturing method of the present embodiment is performed through the following steps for hollow bent parts. Manufacture Pp.
That is, in FIG. 1, first, the long hollow material Pm made of steel is supported by the support device 11 arranged at the first position A while being relatively fed in the longitudinal direction by the feeding device.

Next, the hollow material Pm sent is partially rapidly heated by the heating device 12. Before that, the inclination of the heating coil 12a is set to the inclination angle α, and the inclination of the cooling device 13 is also set to the same inclination angle α.
It is desirable that the heating temperature of the hollow material Pm is at least 3 points of Ac of the steel constituting the hollow material Pm. By setting the number of Acs to 3 or more, the bent portion of the hollow material Pm can be hardened by appropriately setting the cooling rate at the time of cooling performed after heating. Moreover, the deformation resistance between the first portion and the second portion of the hollow material Pm can be sufficiently reduced to such an extent that processing having a desired small bending radius can be performed. ..

Cooling water is injected toward the hollow material Pm from the cooling water injection nozzle 13a of the cooling device 13 arranged at the third position C downstream from the second position B along the feeding direction of the hollow material Pm. .. As a result, the heated portion is cooled at the third position C. Although it depends on the steel type of the hollow material Pm, by setting the cooling rate at the time of cooling to 100 ° C./sec or more, it is possible to quench the bent portion to increase its strength.

By this cooling, the hollow material Pm is formed with a first portion heated by the heating device 12 and a second portion cooled by the cooling device 13. The space between the first portion and the second portion of the hollow material Pm is in a high temperature state, and its deformation resistance is significantly reduced.

When the tip of the planned shear bending process portion of the hollow material Pm reaches the pair of gripping means 14a, 14b of the shearing force applying device 14, the gripping means 14a, 14b is used as a starting point of the hollow material Pm. A support frame (not shown) in a combined direction (diagonally downward to the left of the paper surface in FIG. 1) in which two directions, a feeding direction and a direction substantially parallel to the cross section in the longitudinal direction of the hollow material Pm heated by the heating device 12, are combined. A pair of upper and lower gripping means 14a and 14b rotatably supported by the moving means 14a and 14b are moved. At this time, the shear angle by the shear force applying device 14 is set to θ.
In this way, a shear force Ws is applied between the first portion and the second portion of the hollow material Pm, and the hollow material Pm is subjected to a shear bending process to obtain a hollow bent part Pp. ..

[Hollow bending parts]
The hollow bent part Pp is a hollow and long member made of steel, has a closed cross-sectional shape, and has a bent portion integrally formed in the longitudinal direction. In the hollow bent component Pp of the present embodiment, the bending radius at the bent portion is 0.2 to 2 times the width W which is the distance between the outer curve on the inner peripheral side and the outer curve on the outer peripheral side of the bent portion. It can have at least one bend with an extremely small bend radius, such as: That is, when there are a plurality of bent portions, the extremely small bending radius as described above can be obtained at one or more of the bent portions.

The width W is the outer shape curve on the inner peripheral side in a direction orthogonal to the center line along the bending direction of the bending portion when the bending portion of the hollow bending component Pp is viewed along the bending direction. The product width between the outer circumference curve and the outer circumference curve. If the width W is different at each position along the bending direction of the bent portion, the maximum value in the bent portion is taken as the width W.
The bending radius may be a value obtained for the outer curve on the inner peripheral side, or may be a value obtained for the outer line on the outer peripheral side. Since the bent portion is formed by shear deformation, the bending radius obtained for the outer curve on the inner peripheral side and the bending radius obtained for the outer curve on the outer peripheral side are substantially the same, unlike the case of normal bending deformation. Because it becomes. In actual machining, there may be a slight difference between the bending radius obtained for the outer curve on the inner peripheral side and the bending radius obtained for the outer curve on the outer peripheral side. In that case, the smaller of them may be used as the bending radius.

Under the above provisions, when the hollow bent part Pp is a metal tube with a circular cross section, the bending radius at the bent portion is 1 to 2 times or less (0.2 times to 2) the diameter (outer diameter) of the circular cross section. It can be a very small bending radius (double). Similarly, when the hollow bent part Pp is a rectangular metal pipe, the bending radius at the bent portion is 1 to 2 times or less (0.2 to 2 times) the length of the side of the rectangular cross section in the bending direction. ) Can be an extremely small bending radius.

In addition, in this hollow bent part Pp, the product width W of the shear-bent portion is partially changed or maintained. That is, the product width W includes each of the above-mentioned patterns (a) to (c).
In the hollow bent part Pp thus obtained, in the bent portion subjected to shear bending, when steel is used as a material, the ratio (volume ratio) of martensite in the microstructure is 50% or more. Become.

The outline of this embodiment will be described below.
[1] In the present embodiment, a long hollow metal material Pm is supported at the first position A while being fed in the feeding direction along the longitudinal direction thereof, and is supported at the first position A along the feeding direction. The hollow material Pm is partially heated in the heated portion by the heating device 12 arranged at the second position B downstream of the second position B, and the third position downstream of the second position B along the feeding direction. The hollow material Pm is cooled by the cooling device 13 arranged in C, and the hollow material Pm is supported at the fourth position D downstream from the third position C along the feeding direction to set the support position in the two-dimensional direction. Alternatively, it is a method of manufacturing a hollow bent part that applies a shearing force to the heated portion of the hollow material Pm by moving it in a three-dimensional direction, and the shear formed before and after the application of the shearing force of the hollow material Pm. By setting the inclination angle α of the heating device 12 and the cooling device 13 with respect to the feeding direction according to the angle θ, the width dimension W of the shear bending portion in the hollow material Pm is changed.

[2] In the above [1], when the setting is made, the shear angle is θ (degrees), the inclination angle is α (degrees), and the original width dimension of the hollow material Pm is W ₀ (mm). The width dimension of the shear-bent portion may be set to W (mm), and the shear angle θ and the inclination angle α may be set so as to satisfy the following equation (7).

[3] In the present embodiment, a support device 11 that supports a long metal hollow material Pm at a first position A while feeding it in a feeding direction along the longitudinal direction thereof, and a first support device 11 along the feeding direction. A heating device 12 arranged at a second position B downstream of the position A of 1 and partially heating the hollow material Pm in the heated portion, and a heating device 12 downstream of the second position B along the feeding direction. A cooling device 13 arranged at the third position C to cool the hollow material Pm, and a support position for supporting the hollow material Pm at a fourth position D downstream of the third position C along the feeding direction. Is formed in a shearing force applying device 14 that applies a shearing force to the heated portion of the hollow material Pm by moving the hollow material Pm in a two-dimensional direction or a three-dimensional direction, and before and after applying the shearing force of the hollow material Pm. By setting the inclination angle α of the heating device 12 and the cooling device 13 with respect to the feeding direction according to the shearing angle θ, and controlling the heating device 12, the cooling device 13, and the shearing force applying device 14 based on the setting. , A control device 15 for changing the width dimension W of a shear-bent portion in the hollow material Pm, and a hollow bending component manufacturing device.

[4] In the above [3], the following configuration may be adopted: when the control device 15 makes the setting, the shear angle is set to θ (degree) and the inclination angle is set to α (degree). The original width dimension of the hollow material Pm is W ₀ (mm), the width dimension of the sheared bending portion is W (mm), and the shear angle θ and the inclination angle α are set so as to satisfy the following equation (8). To do.

[5] The present embodiment is a long hollow integral part made of metal, and the width W of the heat-treated bent portion when viewed along the longitudinal direction thereof is the width W of another portion adjacent to the bent portion. Provided is a hollow bending component Pp having a width W ₀ .

[6] In the above [5], the following configuration may be adopted: the cross-sectional shape perpendicular to the longitudinal direction has a rectangular closed cross-sectional shape, and the outer peripheral side wall portion of the bend at the bent portion and the bent portion. The width W between the bent inner peripheral side wall portion and the portion is different from the width W ₀ of the other adjacent portions.

[7] In the above [5] or [6], the following configuration may be adopted: it is made of steel and the amount of martensite at the bent portion is 50% or more.

The effects of the present invention will be described based on Example 1 described below. Tables 1 to 3 show the values of the inclination angle α and the shear angle θ of the heating coil 12a at the time of manufacture for each of Examples 1 to 3 of the present invention. Tables 1 to 3 also show the width ratio W / W ₀ calculated by the above equation (4) for each condition. The product shapes are shown in FIGS. 5A to 5C.

[Example 1 of the present invention]
In Example 1 of the present invention, the heating coil 12a is set perpendicular to the feeding direction of the hollow material Pm (inclination angle α = 90 degrees), and then a shearing force is applied in the region I shown in FIG. 5A. Harden while sending straight without doing. In the subsequent region II, quenching is performed while shearing at a shear angle of θ = 30 degrees, and then in region III, quenching is performed while feeding straight without applying a shearing force. The calculation results are shown in Table 1 below. The width ratio W / W ₀ in each region I to III is as shown in Table 1 below. The product width W of region II that has undergone shear bending is reduced by about 13% with respect to the original width dimension. The appearance of the product corresponding to Example 1 of the present invention is shown in FIG. 5 (a).

[Example 2 of the present invention]
In Example 2 of the present invention, the heating coil 12a was tilted at α = 45 degrees with respect to the feeding direction of the hollow material Pm. Under this setting, in region I, quenching is performed while feeding straight without applying a shearing force. In the subsequent region II, quenching is performed while performing shear bending at a shear angle θ = 30 degrees. In the subsequent region III, quenching is performed while feeding straight without applying a shearing force. The calculation results are shown in Table 2 below. The width ratio W / W ₀ in each region I to III is as shown in Table 2 below. In this manufacturing method, the product width W of the region II subjected to the shear bending process is increased by about 36%. The appearance of the product corresponding to Example 2 of the present invention is shown in FIG. 5 (b).

[Example 3 of the present invention]
In Example 3 of the present invention, the heating coil 12a was tilted at α = 30 degrees with respect to the feeding direction of the hollow material Pm. Under this setting, in region I, quenching is performed while feeding straight without applying a shearing force. In the subsequent region II, quenching is performed while performing shear bending at a shear angle θ = 30 degrees. In the subsequent region III, quenching is performed while feeding straight without applying a shearing force. The calculation results are shown in Table 3 below. The width ratio W / W ₀ in each region I to III is as shown in Table 3 below. In this manufacturing method, the product width W of the region II subjected to the shear bending process is significantly increased to about 73%. The appearance of the product corresponding to Example 3 of the present invention is shown in FIG. 5 (c).

[Confirmation of effect of Example 1]
The manufacturing methods of Examples 1 to 3 of the present invention were carried out by setting the coil inclination angle α and the shear angle θ shown in Tables 1 to 3 above. As a result, 75 products of 0.2% carbon steel, height dimension H ₀ = 30 mm, width dimension W ₀ = 50 mm, plate thickness t ₀ = 1.0 mm, total length L = 1200 mm were produced for each case. , Manufactured as a hollow bent part Pp. The heating temperature of the heated portion by the heating device 12 was set to 950 ° C. Then, when the width dimensions of these hollow bent parts Pp were measured, they were in agreement with an error within ± 5% of the values shown in Tables 1 to 3. Further, the tensile strength of the hollow bent part Pp was 1470 MPa or more over the entire length, and a 100% martensite structure was obtained.

[Example 1 of the present invention]
When the product width W shown in the region II of FIG. 5 is required to be 45.5 mm or less by design, in the conventional manufacturing method, a hollow material Pm having a rectangular cross-section width W ₀ of 45.5 mm is used. Will be done. In Example 1 of the present invention, the product width W can be reduced to 45.5 mm or less while using the hollow material Pm having a width W ₀ of 50 mm. In order to obtain the same product having a different product width W as in Example 1 of the present invention by the conventional manufacturing method, the products in regions I, II, and III are manufactured separately from each other, and then these are welded into one. Need to assemble.

[Example 2 of the present invention]
When the product width W shown in the region II of FIG. 5 is required by design to be 64 mm, in the conventional manufacturing method, a hollow material Pm having a rectangular cross section width W ₀ of 64 mm is used. In Example 2 of the present invention, the product width W can be made 64 mm while using the hollow material Pm having a width W ₀ of 50 mm, so that the weight can be reduced by about 15%. In order to obtain the same product having a different product width W as in Example 2 of the present invention by the conventional manufacturing method, the products in regions I, II, and III are manufactured separately from each other, and then these are welded into one. Need to assemble.

[Example 3 of the present invention]
When the product width W shown in the region II of FIG. 5 is required by design to be 82 mm, in the conventional manufacturing method, a hollow material Pm having a rectangular cross section width W ₀ of 82 mm is used. In Example 3 of the present invention, the product width W can be made 82 mm while using the hollow material Pm having a width W ₀ of 50 mm, so that the weight can be reduced by about 28%. In order to obtain the same product having a different product width W as in Example 3 of the present invention by the conventional manufacturing method, the products in regions I, II, and III are manufactured separately from each other, and then these are welded into one. Need to assemble.

As shown above, the hollow bent part Pp is obtained by conducting an experiment in advance using the formula (5) as a guide and selecting an appropriate hollow material Pm for the product dimensional conditions required for design. Weight reduction is possible.

[Example 4 of the present invention]
Example 4 of the present invention manufactures the hollow bent part Pp shown in FIG.
First, the heating coil 12a is tilted at α = 120 degrees with respect to the feeding direction of the hollow material Pm, and in the region I, quenching is performed while feeding straight without applying a shearing force. In the subsequent region II, the heating coil 12a is hardened while being sheared at a shear angle of θ = 30 degrees while being tilted at α = 120 degrees. After that, the heating coil 12a is hardened while changing the inclination angle from α = 120 degrees to α = 45 degrees and feeding it straight in the region III without applying a shearing force. Subsequently, in the region IV, the heating coil is set to be tilted at α = 45 degrees, and quenching is performed while shearing at a shear angle θ = 30 degrees. Then, while the heating coil is tilted at α = 45 degrees, quenching is performed while feeding the heating coil straight in the region V without applying a shearing force. The calculation results are shown in Table 4 below. Table 4 below shows the width ratio W / W ₀ . In this method, the product width W can be changed in regions II and IV that have undergone shear bending. The appearance of the product corresponding to this example is shown in FIG.

[Confirmation of effect of Example 2]
The manufacturing method of Example 4 of the present invention was carried out by setting the coil inclination angle α and the shear angle θ shown in Table 4. As a result, 50 products of 0.2% carbon steel, height dimension H ₀ = 30 mm, width dimension W ₀ = 50 mm, plate thickness t ₀ = 1.0 mm, total length L = 2000 mm, hollow bent parts Pp. Manufactured as. The heating temperature of the heated portion by the heating device 12 was set to 950 ° C. Then, when the width dimension of these hollow bent parts Pp was measured, they were in agreement with an error within ± 5% of the values shown in Table 4. Further, the tensile strength of the hollow bent part Pp was 1470 MPa or more over the entire length, and a 100% martensite structure was obtained.
In the case where the product width W in the region II of FIG. 6 needs to be 31 mm or less and the product width W in the region IV of FIG. 6 needs to be 64 mm due to interference with other parts by design. According to the manufacturing method of the present invention, it is possible to manufacture using a hollow material Pm having a width of 50 mm. When the same products having different widths are to be obtained by the conventional manufacturing method as in the second embodiment, it is necessary to manufacture the regions I to V individually and to assemble them by welding to each other.

As shown in Examples 1 and 2 of the above description, according to the present embodiment, the bending radius of the bent portion is, for example, 1 to 2 times the length of the side in the bending direction (outer diameter in the case of a circular pipe). It is possible to reliably provide a high-strength hollow bent component Pp having an extremely small bent portion of less than that (0.2 times to 2 times) at a low cost. Moreover, since the width required for the design can be given to the required part of the product in the processing process, weight reduction and process omission can be achieved more than ever. Therefore, according to the present invention, it is possible to increase the degree of freedom in designing various parts of an automobile, such as a vehicle body component and a suspension member of an automobile, and to further reduce the cost and weight of these various parts. ..

As for the product strength, as shown in the hatched portion of FIG. 7, the product made of steel can be partially hardened. By combining the heating temperature of the heated portion of the hollow material Pm and the component composition of the hollow material Pm, the amount of martensite in the hardened portion of the hollow bent part Pp can be controlled. As a preferable mode, a hollow bent part Pp having a relatively high strength can be obtained with a composition in which the amount of martensite in the hardened portion is 50% or more. Therefore, according to the present embodiment, it is possible to increase the degree of freedom in designing various body components of the automobile, and further reduce the cost and weight of these various parts.
In Examples 1 and 2, the case where the shear angle θ was changed discontinuously was illustrated, but by continuously setting the shear angle θ and the corresponding inclination angle α together with the feed of the hollow material Pm, A two-dimensional product or a three-dimensional product having an arbitrary curved shape can be obtained. That is, according to the method and apparatus for manufacturing a hollow bent part according to the present embodiment, not only a two-dimensional product having a bent portion in one plane but also intersecting (including orthogonality) with respect to the same plane as in the one plane. It is also possible to manufacture a three-dimensional product having a bent portion having an arbitrary shape and having a predetermined width both in the other plane.

In the above description, the case where the shear deformation is applied to the hollow metal material Pm having a rectangular cross section has been illustrated, but the present invention is not limited to this aspect. That is, even if the cross-sectional shape of the hollow metal material is a round pipe or polygonal pipe other than a rectangular pipe or a pipe having an arbitrary curved shape, the inclination angle α and the shear angle θ of the heating coil 12a are similarly changed. By doing so, the width of the portion to be subjected to the shear bending process can be changed.

Further, since the width can be changed by adding the deformation due to the shearing force to the conventional bending deformation, the processing including the deformation component due to the shearing force is the object of the present invention.
The hollow bent part Pp according to the present invention is manufactured by performing heat treatment (for example, quenching) at the same time as processing by shearing force. Therefore, a hollow bent part Pp having a high-strength portion of, for example, 1470 MPa or more, is a simpler process as compared with a hollow bent part which is subjected to cold shear bending and then heat treatment (for example, quenching). Moreover, it can be manufactured with high processing accuracy.

The hollow bent part Pp manufactured by the manufacturing method according to the present invention can be applied to, for example, the uses (i) to (vii) illustrated below.
(I) Structural members of automobile bodies such as front side members, cross members, side members, suspension members, roof members, A-pillar reinforcements, B-pillar reinforcements, bumper reinforcements, etc. (ii) For example, seats. Automobile strength members and reinforcement members such as frames and seat cross members (iii) Exhaust system parts such as automobile exhaust pipes (iv) Frames and cranks of bicycles and motorcycles (v) Reinforcement members and trolley parts of vehicles such as trains (Vehicle frame, various beams, etc.)
(Vi) Frame parts such as hulls, reinforcing members (vi) Strength members, reinforcing members or structural members of home appliances

[Additional Notes]
(A) A method for processing a metal material in which a work material held by the support means is sequentially or continuously fed from the upstream side and bent on the downstream side of the support means, and is on the downstream side of the support means. The metal material is clamped by the shearing force applying means provided in the above, and while controlling the position and / and the moving speed of the shearing force applying means, it is arranged on the entrance side of the shearing force applying means and on the outer periphery of the metal material. The metal material is heated to a temperature range in which plastic deformation is locally possible and a temperature range in which quenching is possible, and then a shearing force is applied to the heated portion, and then the metal material is rapidly cooled by using the heating means and the cooling means. In the method of processing a metal material, the product width is set by setting α inclination of the heating means and the cooling means with respect to the longitudinal direction of the hollow metal material with respect to the angle θ formed by the traveling direction of the processed product. A method for manufacturing a hollow bending member, which comprises changing.

(B) A method for processing a metal material in which a work material held by the support means is sequentially or continuously fed from the upstream side and bent on the downstream side of the support means, and is on the downstream side of the support means. The metal material is clamped by the shearing force applying means provided in the above, and while controlling the position and / and the moving speed of the shearing force applying means, it is arranged on the entrance side of the shearing force applying means and on the outer periphery of the metal material. The metal material is heated to a temperature range in which plastic deformation is locally possible and a temperature range in which quenching is possible, and then a shearing force is applied to the heated portion, and then the metal material is rapidly cooled by using the heating means and the cooling means. In the method of processing a metal material, the heating means and the cooling means are shown in the following equation (9) with respect to the longitudinal direction of the hollow metal material with respect to the angle θ formed by the traveling direction of the processed product. A method for manufacturing a hollow bending member, which comprises changing the product width by setting an inclination.

(C) An integrally hollow bent part made of metal, characterized in that the widths of the parts are partially different and a part of the parts is heat-treated.

(D) The metal hollow integral part according to (c) above, characterized in that the hollow part is made of steel and the amount of martensite in the partially heat-treated portion is 50% or more. Body hollow bending parts.

12 Heating device (heating means)
13 Cooling device (cooling means)
14 Shear force applying means (shear force applying device)
15 Control device (control means)
A 1st position B 2nd position C 3rd position D 4th position Pm Hollow material Pp Hollow bending part α Tilt angle θ Shear angle

Claims (7)

A long hollow metal material is supported in the first position while being fed in the feeding direction along its longitudinal direction.
The hollow material is partially heated in the heated portion by a heating means arranged at a second position downstream of the first position along the feeding direction.
The hollow material is cooled by a cooling means arranged at a third position downstream of the second position along the feed direction.
By supporting the hollow material at a fourth position downstream of the third position along the feed direction and moving the support position in the two-dimensional direction or the three-dimensional direction, the hollow material is heated. Gives shearing force to the part,
It is a manufacturing method of hollow bent parts.
By setting the inclination angles of the heating means and the cooling means with respect to the feeding direction according to the shear angles formed before and after the application of the shearing force of the hollow material, the shear-bent portion in the hollow material. A method for manufacturing a hollow bent part, which is characterized by changing the width dimension of. When making the above settings, the shear angle is θ (degrees), the inclination angle is α (degrees), the original width dimension of the hollow material is W ₀ (mm), and the width dimension of the shear-bent portion. The method for manufacturing a hollow bent part according to claim 1, wherein W (mm) is set and the shear angle and the inclination angle are set so as to satisfy the following formula (1).

A support device that supports a long hollow metal material in the first position while feeding it in the feed direction along its longitudinal direction.
A heating means that is arranged at a second position downstream of the first position along the feed direction and partially heats the hollow material in the heated portion.
A cooling means arranged at a third position downstream of the second position along the feed direction to cool the hollow material, and
By supporting the hollow material at a fourth position downstream of the third position along the feed direction and moving the support position in the two-dimensional direction or the three-dimensional direction, the hollow material is heated. Shear force applying means that gives shear force to the part,
The inclination angles of the heating means and the cooling means with respect to the feeding direction are set according to the shear angles formed before and after the application of the shearing force of the hollow material, and the heating means and the heating means are set based on the settings. Control means for changing the width dimension of the shear-bent portion in the hollow material by controlling the cooling means and the shearing force applying means.
A device for manufacturing hollow bent parts, which comprises. When the control means makes the setting, the shear angle is set to θ (degrees), the inclination angle is set to α (degrees), the original width dimension of the hollow material is set to W ₀ (mm), and the shear bending is performed. The apparatus for manufacturing a hollow bent part according to claim 3, wherein the width dimension of the processed portion is W (mm), and the shear angle and the inclination angle are set so as to satisfy the following formula (2).

A hollow integral part made of metal, characterized in that the width of the heat-treated bent portion along the longitudinal direction thereof is different from the width of other portions adjacent to the bent portion. Bending parts. The cross-sectional shape perpendicular to the longitudinal direction has a circular or rectangular closed cross-sectional shape.
The hollow bend according to claim 5, wherein the bent portion has a bending radius of not more than twice the width, which is a dimension between the outer shape on the inner peripheral side and the outer shape on the outer peripheral side of the bent portion. parts. Made of steel
The amount of martensite at the bend is 50% or more.
The hollow bent part according to claim 5 or 6.

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