Manufacturing apparatus for hollow bent component and manufacturing method for hollow bent component

Abstract

To provide a manufacturing device of a hollow bending component which performs shear bending process with high processing accuracy, and to provide a manufacturing method of the hollow bending component.SOLUTION: A manufacturing device 10 of a hollow bending component includes: a feeding device 11; a support device 12; a heating coil 13a; a coolant injection nozzle 14a; holding means 15Aa, 15Ab; an arm part 15Ac; and a control device 16. The control device 16 controls the holding means 15Aa, 15Ab or the arm part 15Ac so that a distance L' from a downstream end position P0 along a feed direction F of a support range of a hollow material Pm by the support device 12 to a center position P2 along the feed direction F of the support range of the hollow material Pm by the holding means 15Aa, 15Ab is limited within a predetermined distance during a time period from the start to the end of the shear bending process.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an apparatus for manufacturing a hollow bent component and a method for manufacturing a hollow bent component.

Background Art

[0002] As is well known, metal strength members, reinforcing members, or structural members having a hollow and bent shape used in automobiles and various machines are required to be lightweight and high-strength. Conventionally, this type of hollow bent component has been manufactured by, for example, cold bending, welding of press-worked products, punching of thick plates, and further forging. However, in these manufacturing methods, there are limitations in reducing the weight and increasing the strength of the manufactured hollow bent component, and its realization has not been easy.

[0003] In recent years, for example, as disclosed in Non-Patent Document 1, actively manufacturing this type of hollow bent component by the so-called tube hydroforming method has also been studied. However, as also described on page 28 of Non-Patent Document 1, the tube hydroforming method has problems such as the development of materials to be used and the expansion of the degree of freedom of formable shapes, and further development is required in the future.

[0004] In view of such a situation, the present inventors previously disclosed an invention related to a hot bending apparatus in Patent Document 1. FIG. 7 shows an embodiment of the invention in Patent Document 1, and is an explanatory view schematically showing the schematic configuration of this hot bending apparatus 100. As shown in Fig. 7, in this hot bending processing apparatus 100, a steel pipe (hereinafter, hollow material Pm) supported by a support means 101 (a pair of support means 101a and 101b) so as to be movable in its axial direction is fed in the direction of arrow F from the upstream side to the downstream side by a feeding device (not shown), and bending processing is performed at a position downstream of the support means 101a and 101b to manufacture a steel hollow bent part Pp. That is, at a position downstream of the support means 101a and 101b, the hollow material Pm is rapidly heated to a temperature range where it can be quenched partially by a high-frequency heating coil 102, and the hollow material Pm is rapidly cooled by a water cooling device 103 disposed downstream of the high-frequency heating coil 102. Then, the tip of the hollow material Pm is gripped by a gripping means 104 (a pair of gripping means 104a and 104b), and the position of the gripping means 104 is changed in three-dimensional directions (in some cases, two-dimensional directions) to apply a bending moment to the heated portion of the hollow material Pm, thereby performing bending processing on the hollow material Pm. According to this hot bending processing apparatus 100, it becomes possible to manufacture a high-strength hollow bent part Pp with high working efficiency.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Among the hollow bent parts used in automobiles, various machinery, etc., there are those with various shapes. In particular, there are many hollow bent parts having extremely small bent parts where the bending radius of the bent part is, for example, 1 to 2 times or less than the diameter of a metal pipe (in the case of a rectangular cross-section, the length of the side in the bending direction). However, when bending is performed by the method of Patent Document 1 so as to have a bending radius of 1 to 2 times or less than the diameter of a metal pipe (in the case of a rectangular cross-section, the length of the side in the bending direction), there is a risk that wrinkles or folds may occur on the inner peripheral side of the bent part, or the plate thickness on the outer peripheral side of the bent part may be greatly reduced and break. Therefore, it has been difficult to manufacture hollow bent parts having small bent parts. Furthermore, in the cold bending process of hollow bent parts, as described in Non-Patent Document 2, since tensile stress acts on the outer peripheral side of the bent part, the plate thickness decreases. Similarly, since the method of Patent Document 1 is also a bending process, the reduction in the plate thickness on the outer peripheral side of the bent part cannot be avoided.

[0008] Therefore, in order to solve these problems, the inventors have disclosed an invention related to a hot shear bending processing apparatus according to Patent Document 2. As shown in Fig. 8, this hot shear bending processing apparatus 200 includes a first support means 201 (a pair of support means 201a and 201b), a heating means 202, a cooling means 203, and a gripping means 204. The pair of support means 201a and 201b support a metal hollow material Pm at a first position A1 while relatively feeding it in its longitudinal direction. The heating means 202 partially heats the hollow material Pm at a second position B1 downstream of the first position A1 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 a third position C1 downstream of the second position B1 along the feeding direction of the hollow material Pm. The gripping means 204 applies a shearing force to the heated portion of the hollow material Pm by positioning the hollow material Pm at a fourth position D1 downstream of the third position C1 along the feeding direction of the hollow material Pm and moving it in a two-dimensional or three-dimensional direction. Therefore, according to this hot shear bending processing apparatus 200, it becomes possible to apply shearing processing and heat treatment to the heated portion of the hollow material Pm. And according to this shear bending processing apparatus 200, it is possible to mass-produce high-strength hollow bent parts Pp having a bent portion with a bending radius of 1 to 2 times the diameter of the metal pipe (the length of the side in the bending direction in the case of a rectangular cross-section) or less at low cost. According to the invention of this Patent Document 2, it becomes possible to manufacture hollow bent parts Pp having a small bending radius while being high-strength, and a significant weight reduction of a large number of machine parts including automobiles can be achieved.

[0009] Furthermore, Patent Document 3 discloses a shear bending processing apparatus 300 shown in Fig. 9 and a method for manufacturing a hollow bent part using this apparatus. In the shear bending processing apparatus 300, the shearing angle applied to the hollow material Pm is θ (degrees), and the inclination angle of the heating device 301 and the cooling device 302 with respect to the feeding direction of the hollow material Pm is α (degrees). With this configuration, while partially increasing the product plate thickness of the hollow bent part Pp, it is also possible to achieve weight reduction according to various design needs.

[0010] In the hot bending process or hot shear bending process described above, bending is performed by applying a bending force or a shearing force to a region that becomes hot due to heating from the heating means and has a reduced deformation resistance (hereinafter referred to as the deformation region). Here, when the distance from the deformation region to the gripping means for applying the bending force or the shearing force is L, the relationship between the distance L and the processing force is as shown in Fig. 10(a). Also, the relationship between the distance L and the moment acting on the deformation region is as shown in Fig. 10(b).

[0011] As shown in Fig. 10(b), the hot bending deformation for obtaining a predetermined bending radius is caused by the moment Mb. The moment Mb is applied by moving the gripping means for gripping the tip of the hollow material Pm along a predetermined trajectory. Here, in the hot bending process, the moment Mb required to obtain a predetermined bending deformation, assuming the processing force Wb and the distance L between the gripping means and the deformation region, is Mb = Wb × L. Therefore, in the hot bending process, as shown in Fig. 10(a), the processing force Wb decreases as the distance L increases. On the other hand, as shown in Fig. 10(a), the deformation in the hot shear bending process is caused by the processing force Ws applied by the gripping means. And in the hot shear bending process, the processing force Ws required to obtain a predetermined bending deformation is constant regardless of the distance L. Therefore, in the hot shear bending process, as shown in Fig. 10(b), the moment Ms increases as the distance L increases.

[0012] Therefore, in hot shear bending, as the gripping means moves downstream due to the processing force Ws, the hollow material elastically deforms with the support means as the fulcrum, and the deflection due to this elastic deformation increases. When the elastic deflection increases, the hollow material may come into contact with the heating means, or it may become difficult to manufacture the hollow bent part. Since the portion of the hollow material downstream of the heating means also elastically deforms, the relative position between the heating means and the hollow material changes from the original position. In this case, the product accuracy deteriorates without a predetermined deformation being applied. Furthermore, the gripping means may rigidly rotate under a large moment from the hollow material. In this case, since a predetermined shear deformation cannot be applied, the product accuracy deteriorates. Also, in order to avoid the rigid rotation of the gripping means, it is necessary to increase the rigidity on the equipment side, and there is a problem that the equipment becomes larger.

[0013] For the reasons described above, when manufacturing a hollow bent part by shear bending, a processing technique capable of obtaining higher processing accuracy is desired.

[0014] The present invention has been made in view of the above circumstances, and an object thereof is to provide a manufacturing apparatus and a manufacturing method for a hollow bent part capable of performing shear bending with high processing accuracy.

Means for Solving the Problems

[0015] In order to solve the above problems, the present invention employs the following means. (1) A manufacturing apparatus for a hollow bent part according to one aspect of the present invention includes a feeding unit that moves a metal hollow workpiece in its longitudinal direction, support means that supports the workpiece in a state where movement in a direction orthogonal to the longitudinal direction is restricted and movement in the feeding direction along the longitudinal direction is allowed, a heating coil that is disposed so as to surround the workpiece on the downstream side of the support means in the feeding direction and heats the workpiece, a cooling unit that cools the workpiece on the downstream side of the heating coil in the feeding direction, Gripping means for gripping the workpiece at a gripping position on the downstream side in the feeding direction from the cooling section, An operation section for moving the gripping means, A control section for controlling the feeding section, the heating coil, the cooling section, the gripping means, and the operation section, and comprising, An apparatus for applying a shear bending process to the workpiece by moving the gripping means in a two-dimensional or three-dimensional direction by the operation section, wherein the control section, during the start to end of the shear bending process, limits the distance from the most downstream end position along the feeding direction of the support range of the workpiece by the support means to the central position along the feeding direction of the support range of the workpiece by the gripping means within a predetermined distance, and controls the gripping means and the operation section.

[0016] According to the manufacturing apparatus for a hollow bent part described in (1) above, the workpiece is partially heated by the heating coil to form a heated portion. Then, while the upstream side of the workpiece with the heated portion sandwiched therebetween is supported by the support means and the downstream side is gripped by the gripping means, the gripping means is moved in a two-dimensional or three-dimensional direction by the operation section. By moving the gripping means by the operation section, a shear bending process is applied to the heated portion of the workpiece. During the start to end of this shear bending process, the control section limits the distance from the most downstream end position of the support range of the workpiece by the support means to the central position of the support range of the workpiece by the gripping means within a predetermined distance. As a result, the distance between the heated portion of the workpiece and the gripping means becomes shorter. In this way, by gripping the workpiece at a position close to its heated portion and performing a shear bending process, the force point is close to the action point, and the deflection due to the bending moment according to the distance between the force point and the action point is reduced. As a result, compared to the case of performing a shear bending process by gripping the workpiece at its downstream end as in the prior art, the distance between the heated portion and the gripping means is shortened, the deflection of the workpiece at this portion is suppressed, and a shear bending process can be performed. Therefore, the processing accuracy of the manufactured hollow bent part is improved. In addition, when using a sliding type that does not require control as the supporting means and a roller type that restricts only the movement in the direction orthogonal to the feeding direction of the steel pipe, the supporting means is excluded from the control target of the control device. On the other hand, when the supporting means itself is also provided with a function as a feeding section for feeding the workpiece, the supporting means is also included in the control target of the control device.

[0017] (2) In the manufacturing apparatus for a hollow bent part according to (1) above, When the average width dimension of the workpiece before performing the shearing and bending process is w (mm), the predetermined distance may be set to 20 × w (mm) or less. According to the manufacturing apparatus for a hollow bent part described in (2) above, the distance between the supporting means and the gripping means can be appropriately shortened to effectively suppress the deflection of the workpiece in this part, and then the shearing and bending process can be performed.

[0018] (3) In the manufacturing apparatus for a hollow bent part according to (1) or (2) above, it may be configured as follows: The gripping means A first gripping state that allows relative movement of the workpiece along the longitudinal direction with respect to the gripping means, and A second gripping state that restricts relative movement of the workpiece along the longitudinal direction with respect to the gripping means, and Are configured to be switchable between, The control unit switches between the first gripping state and the second gripping state of the gripping means. According to the manufacturing apparatus for the hollow bent part described in the above (3), when quenching is performed on the workpiece while it remains a straight pipe without performing shearing and bending on the workpiece, the control unit sets the gripping means to the first gripping state. The gripping means in this first gripping state guides and supports the workpiece while allowing only relative movement along its longitudinal direction. Thereby, since the portion of the workpiece near the heated portion can be continuously supported and then fed while being quenched, the occurrence of deflection can be suppressed. Also, before performing the shearing and bending process, the control unit switches the gripping means from the first gripping state to the second gripping state, thereby restricting the relative movement of the workpiece with respect to the gripping means. Thereby, the distance between the support means and the gripping means can be kept short, and the shearing and bending process can be performed while suppressing the deflection of the workpiece at this portion.

[0019] (4) In the manufacturing apparatus for the hollow bent part described in the above (3), it may be configured as follows: The gripping means is configured to be able to approach and separate from the outer peripheral surface of the workpiece, and in the first gripping state, a roller that is rotatably in contact with the outer peripheral surface of the workpiece, and configured to be able to approach and separate from the outer peripheral surface, and in the second gripping state, a clamper that is in contact with the outer peripheral surface of the workpiece, and includes. According to the manufacturing apparatus for the hollow bent part described in the above (4), in the first gripping state, without changing the gripping position, the workpiece can be guided in the longitudinal direction by the rolling of the roller while restricting the movement in the radial direction orthogonal to the longitudinal direction. On the other hand, in the second gripping state, the movement of the workpiece along the longitudinal direction can also be restricted by the contact of the clamper.

[0020] (5) In the manufacturing apparatus for the hollow bent part according to any one of the above (1) to (4), it may have a plurality of the gripping means and the operation unit respectively. According to the manufacturing apparatus for the hollow bent part described in the above (5), instead of the gripping means that performs shear bending processing and moves downstream while holding the workpiece, another gripping part can perform the next shear bending processing while gripping the workpiece within the predetermined distance. Therefore, it is possible to handle the processing of extremely long hollow bent parts and the processing that performs shear bending processing a plurality of times.

[0021] (6) A method for manufacturing a hollow bent part according to an aspect of the present invention is as follows. A feeding step of feeding and supporting a metal hollow workpiece while restricting movement in a direction orthogonal to the longitudinal direction at a support position in the middle of the longitudinal direction thereof along a feeding direction along the longitudinal direction. A heating step of partially heating the workpiece by a heating coil arranged so as to surround the periphery of the workpiece at a heating position downstream of the support position to form a heated part. A cooling step of cooling the workpiece at a cooling position downstream of the heating position. A shear bending process step of gripping a gripped part of the workpiece by gripping means at a gripping position downstream of the cooling position, and applying a shear bending process to the workpiece by moving the gripping means in a two-dimensional direction or a three-dimensional direction. It has During the start to end of the shear bending process, The distance from the most downstream end position along the feeding direction of the support range of the workpiece at the support position to the central position along the feeding direction of the gripped part at the gripping position is restricted within a predetermined distance.

[0022] According to the method for manufacturing a hollow bent part described in the above (6), the workpiece is partially heated by a heating coil to form a heated portion. Then, while the workpiece is supported at the upstream side at the support position with the heated portion sandwiched therebetween and the downstream side is gripped by a gripping means, the gripping means is moved in a two-dimensional direction or a three-dimensional direction. By this movement of the gripping means, shear bending is imparted to the heated portion of the workpiece. During the period from the start to the end of this shear bending process, the distance from the most downstream end position of the support range of the workpiece at the support position to the central position of the gripped portion at the gripping position is restricted within a predetermined distance. As a result, the distance between the heated portion of the workpiece and the gripping means becomes shorter. In this way, by gripping the workpiece at a position close to its heated portion and performing shear bending processing, the point of force approaches the point of action, and the deflection according to the distance between the point of force and the point of action is reduced. As a result, compared with the case of performing shear bending processing by gripping the workpiece at its downstream end as in the prior art, the distance between the support position and the gripping means is shortened, the deflection of the workpiece at this portion is suppressed, and then shear bending processing can be performed. Therefore, the processing accuracy of the manufactured hollow bent part is improved.

[0023] (7) In the method for manufacturing a hollow bent part described in the above (6), when the average width dimension of the workpiece before performing the shear bending process is w (mm), the predetermined distance may be set to 20 × w (mm) or less. According to the method for manufacturing a hollow bent part described in the above (7), the distance between the support position and the gripping means can be appropriately shortened, the deflection of the workpiece at this portion can be effectively suppressed, and then shear bending processing can be performed.

[0024] (8) In the method for manufacturing a hollow bent part described in the above (6), the predetermined distance may be set based on the shear load of the workpiece. According to the method for manufacturing a hollow bent part described in the above (8), deflection can be more effectively suppressed according to the shape and material of the workpiece.

[0025] (9) In the method for manufacturing a hollow bent part according to any one of the above (6) to (8), Before starting the shearing and bending process, The gripping means may be switched from a first gripping state in which the gripping means grips while allowing movement of the workpiece along the longitudinal direction of the workpiece to a second gripping state in which movement of the workpiece along the longitudinal direction of the workpiece is restricted. According to the method for manufacturing a hollow bent part described in (9) above, when quenching is performed on the workpiece while it remains a straight pipe without performing shearing and bending on the workpiece, by setting the gripping means to the first gripping state, it is possible to continue to support the portion of the workpiece close to the heated portion and perform quenching while feeding, so that the occurrence of deflection can be suppressed. Further, before performing the shearing and bending process, by switching the gripping means from the first gripping state to the second gripping state, the relative movement of the workpiece with respect to the gripping means is restricted. As a result, the distance between the support position and the gripping means is shortened, the deflection of the workpiece in this portion is suppressed, and then the shearing and bending process can be performed.

Effect of the Invention

[0026] According to the manufacturing apparatus and manufacturing method of the hollow bent part according to each of the above aspects of the present invention, shearing and bending can be performed with high processing accuracy.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0028] Hereinafter, a manufacturing apparatus and a manufacturing method for a hollow bent member according to each embodiment of the present invention will be described with reference to the drawings. In the following description, a case where a hollow steel square tube having a rectangular cross-sectional shape is used as a workpiece (hereinafter, hollow material Pm) and a hollow bent member Pp is manufactured will be exemplified and described.

[0029] [First Embodiment] First, a manufacturing apparatus (hereinafter, manufacturing apparatus 10) for a hollow bent member to which this manufacturing method is applied will be described first, and then the manufacturing method will be described.

[0030] [Manufacturing Apparatus for Hollow Bent Member] FIG. 1 is a schematic diagram showing the configuration of the manufacturing apparatus 10 according to the present embodiment. By using this manufacturing apparatus 10 to perform hot bending and shearing processing (hereinafter simply referred to as shearing and bending processing) on the hollow material Pm, a hollow bent member Pp shown in FIG. 2(f) described later is obtained. The hollow material Pm is a long steel square tube having a closed cross-sectional shape of a hollow rectangle with a cross-section perpendicular to its longitudinal direction. Note that the hollow material Pm to be processed in this embodiment is not limited to a square tube, and may be, for example, a tube having a circular, elliptical, or various irregular cross-sectional shapes. The hollow material Pm having a rectangular cross-section may have a square or rectangular cross-sectional shape. The hollow material Pm may be a metal tube other than a steel pipe.

[0031] As shown in FIG. 1, this manufacturing apparatus 10 includes a feeding device (feeding section) 11, a supporting device (supporting means) 12, a heating device 13, a cooling device (cooling section) 14, a shearing force applying device 15, and a control device (control section) 16. (1) Feeding device 11 As shown in FIG. 1, the feeding device 11 feeds the hollow material Pm supported by the supporting device 12 in the longitudinal direction (the left direction of the paper surface along the arrow F) at a predetermined feeding speed. The feeding device 11 is exemplified by a type using an electric servo cylinder, but is not limited to a specific type, and types using a ball screw, a timing belt, a chain, etc. can also be adopted. After the portion where the supporting device 12 is installed on the hollow material Pm passes through the first position A, the hollow material Pm is further fed in the direction of the arrow F by the feeding device 11.

[0032] (2) Supporting device 12 The supporting device 12 includes a plurality of sets (two sets in the example of FIG. 1) of rolls 12a and 12b. One set of rolls 12a sandwiches and supports the hollow material Pm therebetween. Similarly, one set of rolls 12b also sandwiches and supports the hollow material Pm therebetween. Another set of rolls 12a is adjacently arranged at a downstream position of one set of rolls 12b. By these rolls 12a and 12b, the hollow material Pm is supported at the first position A. Note that as the support device 12, it is only necessary to be able to support the hollow material Pm so as to be movable along its feeding direction F, and support devices with other configurations may also be adopted. For example, the support device 12 may be configured to be slidably supported without the rolls 12a and 12b. The support device 12 is fixedly arranged on a mounting table (not shown). However, it is not limited to this mode. For example, the support device 12 may be supported by an end effector (not shown) of an industrial robot. Further, by rotating the rolls 12a and 12b, the support device 12 may be provided with a feeding function for feeding the hollow material Pm, and the feeding device 11 may be omitted. In this case, the support device 12 will also serve as a feeding part for moving the hollow material Pm in its longitudinal direction and a supporting means for supporting the hollow material Pm.

[0033] (3) Heating device 13 The heating device 13 is arranged to perform heating at a second position B downstream of the first position A in the feeding direction F of the hollow material Pm. The heating device 13 heats the entire circumference of the cross section in a part of the longitudinal direction of the hollow material Pm sent through the support device 12. An induction heating device is used as the heating device 13. This induction heating device has a heating coil 13a for high-frequency induction heating of the hollow material Pm. The heating coil 13a of the heating device 13 is arranged to surround the entire circumference of the cross section in a part of the longitudinal direction of the hollow material Pm at a predetermined interval from the outer surface of the hollow material Pm. The hollow material Pm is partially and rapidly heated by the heating device 13 at its heated part H. The position of the highest temperature reached at the heated part H is slightly downstream of the position of the downstream end face of the heating coil 13a, and moves slightly upstream or downstream depending on various conditions such as the way of spraying cooling water from the cooling device 14 described later. Therefore, the most downstream end position P1 of the heating coil 13a is used as a reference position corresponding to the position of the highest temperature reached at the heated part H. This most downstream end position P1 is the most downstream position in the feeding direction F when the outer shape of the heating coil 13a is viewed along the central axis CL. The installation means (not shown) of the heating device 13 may be configured such that the heating coil 13a can be arranged at the second position B with an adjustable tilt angle. That is, the installation means of the heating device 13 may include a rotating means (not shown) for tilting the heating coil 13a at an angle set with respect to the feeding direction F of the hollow material Pm.

[0034] When the hollow material Pm is a round tube, the cross-sectional shape of the heating coil 13a of the heating device 13 is preferably circular. Specifically, when viewed in a direction facing along the central axis CL along the longitudinal direction of the hollow material Pm, the shape of the heating coil 13a is preferably a concentric circular shape having a uniform clearance with respect to the outer peripheral surface of the hollow material Pm. On the other hand, when the hollow material Pm has a non-circular cross-sectional shape including a rectangle, the shape of the heating coil 13a when viewed in a direction facing along the central axis CL of the hollow material Pm is preferably a shape having a clearance suitable for heating with respect to the outer peripheral surface of the hollow material Pm. The central axis CL is the central axis of the hollow material Pm at the position of the support device 12.

[0035] As the installation means of the heating device 13, for example, the end effector of a well-known and commonly used industrial robot can be exemplified, but other installation means can also be adopted. A single-arm robot or an existing device having an arm and a motor, etc. can also be adopted.

[0036] (4) Cooling device 14 The cooling device 14 cools the hollow material Pm at a third position C downstream of the second position B along the feeding direction F of the hollow material Pm. The cooling device 14 rapidly cools the portion of the hollow material Pm located downstream of the portion heated at the second position B. By this cooling, in the hollow material Pm, the region between the heated portion H heated by the heating device 13 and the cooled portion cooled by the cooling device 14 becomes a state where it is at a high temperature and the deformation resistance is significantly reduced.

[0037] The cooling device 14 only needs to be able to obtain a desired cooling rate and is not limited to a cooling device of a specific type. Generally, 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 plurality of cooling water injection nozzles 14a are arranged on the immediately downstream side of the heating device 13, separated from the outer surface of the hollow material Pm so as to surround a partial cross section in the longitudinal direction of the hollow material Pm. Cooling water is injected from these cooling water injection nozzles 14a toward the outer surface of the hollow material Pm.

[0038] Among the heated portions H of the hollow material Pm heated by the heating device 13, the portion located on the downstream side thereof is rapidly cooled by the cooling water injected from the cooling device 14. Thereby, it is also possible to increase the strength of part or all of the bent portion of the hollow material Pm subjected to shear bending processing to a tensile strength of, for example, 1500 MPa or more.

[0039] The installation means of the cooling device 14 only needs to be means capable of arranging the cooling device 14 at the third position C and is not limited to a specific installation means. In order to manufacture the hollow bent member Pp having high dimensional accuracy by the manufacturing apparatus 10 of the present embodiment, it is desirable to set the distance between the second position B and the third position C as short as possible, so as to make the region between the heated portion H heated by the heating device 13 and the cooled portion cooled by the cooling device 14 as small as possible. For this purpose, it is desirable to arrange the cooling water injection nozzles 14a close to the heating coil 13a. Therefore, it is desirable to arrange the cooling water injection nozzles 14a at a position immediately after the heating coil 13a. Further, the cooling device 14 may be fixed to the installation means of the heating device 13. In this case, it is also possible to incline both the cooling water injection nozzles 14a and the heating coil 13a at the same inclination angle while maintaining the relative positional relationship between each cooling water injection nozzle 14a and the heating coil 13a.

[0040] The installation means of the cooling device 14 may be provided separately from the installation means of the heating device 13. In this case, the installation means of the cooling device 14 (not shown) can arrange each cooling water injection nozzle 14a so that the inclination angle can be adjusted at the third position C. That is, the installation means of the cooling device 14 can incline the cooling device 14 at an angle set with respect to the feeding direction F of the hollow material Pm. As the installation means of the cooling device 14, an end effector of a conventional industrial robot can be exemplified, but other installation means can also be adopted. A single-arm robot or an existing device having a rotating means such as an arm and a motor can also be adopted.

[0041] (5) Shearing force applying device 15 The shearing force applying device 15 is arranged downstream of the third position C along the feeding direction F of the hollow material Pm. The shearing force applying device 15 grips an intermediate position in the longitudinal direction of the hollow material Pm and moves this gripping position in a two-dimensional or three-dimensional direction. Specifically, the gripping position of the hollow material Pm in the shearing force applying device 15 is moved in an inclined direction between the feeding direction F along the longitudinal direction of the hollow material Pm and the direction orthogonal to the longitudinal direction of the hollow material Pm as viewed in a cross section including the central axis CL. Thereby, the shearing force applying device 15 applies a shearing force to at least a part of the region between the heated portion H heated by the heating device 13 and the cooled portion cooled by the cooling device 14 in the hollow material Pm to perform a shearing bending process on the hollow material Pm.

[0042] As shown in FIG. 1, the shearing force applying device 15 has a pair of arms 15A and 15B and a base (not shown). Instead of the configuration including both of the arms 15A and 15B, a configuration including only one of them may be adopted. The arm 15A has gripping means 15Aa and 15Ab for gripping the hollow material Pm at a fourth position D1 downstream of a third position C along the feeding direction F of the hollow material Pm, and an arm part (operating part) 15Ac that supports the gripping means 15Aa and 15Ab and moves their positions in a two-dimensional or three-dimensional direction. The arm part 15Ac is supported by the base. The gripping means 15Aa and 15Ab grip the hollow material Pm therebetween by approaching each other. On the other hand, the gripping means 15Aa and 15Ab release the gripping of the hollow material Pm by separating from each other.

[0043] When the gripping means 15Aa and 15Ab are closed to grip the hollow material Pm, the central position in the longitudinal direction of the support range where the gripping means 15Aa and 15Ab contact the hollow material Pm is defined as the gripping position P2. Then, the distance parallel to the feeding direction F between the most downstream end position P0 where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 is shown in FIG. 1 using the symbol L'. This distance L' is maintained within a predetermined distance by the arm part 15Ac receiving an instruction from a control device 16 described later and adjusting the positions of the gripping means 15Aa and 15Ab during the shearing bending process.

[0044] The cross section of a part of the hollow material Pm in the longitudinal direction is heated by the heating device 13, and the deformation resistance is significantly reduced. Therefore, by moving the positions of the pair of gripping means 15a and 15b in a two-dimensional or three-dimensional direction at a fourth position D1 downstream of a third position C along the feeding direction F of the hollow material Pm, a shearing force can be applied to the region between the heated part H heated by the heating device 13 and the cooled part cooled by the cooling device 14 in the hollow material Pm. When a shearing force acts on the hollow material Pm, the middle position in its longitudinal direction bends as shown in FIG. 1. In this embodiment, instead of applying a bending moment to the heated portion of the hollow material Pm as in the invention disclosed in Patent Document 1, a shearing force is applied. For this reason, it is possible to manufacture a hollow bent part having a bent portion with a very small bending radius, for example, 1 to 2 times or less the diameter of a metal pipe (in the case of a rectangular cross section, the length of the side in the bending direction).

[0045] The arm 15B has the same configuration as the arm 15A. FIG. 1 shows a state in which the gripping of the hollow material Pm is released at a fifth position D2 downstream of a fourth position D1 along the feeding direction F of the hollow material Pm. The arm 15B has gripping means 15Ba and 15Bb capable of gripping the hollow material Pm, and an arm portion 15Bc (operating portion) that supports the gripping means 15Ba and 15Bb and moves their positions in a two-dimensional or three-dimensional direction. The arm portion 15Bc is supported by the base in the same manner as the arm portion 15Ac. The gripping means 15Ba and 15Bb can grip the hollow material Pm therebetween by approaching each other. On the other hand, the gripping means 15Ba and 15Bb release the gripping of the hollow material Pm by separating from each other as shown in FIG. 1. The gripping of the hollow material Pm is performed by either one of the arms 15A and 15B. That is, when performing shear bending processing on the hollow material Pm, either one of the arms 15A and 15B grips the hollow material Pm at the fourth position D1, and the other releases the gripping of the hollow material Pm and retracts to a position other than the fourth position D1. Further, when feeding the hollow material Pm while quenching it as a straight pipe along the feeding direction F, the one that grips at the fourth position D1 among the arms 15A and 15B moves in the feeding direction F so as to move away from the fourth position D1 while maintaining the gripping state. And the other of the arms 15A and 15B moves to the fourth position D1 in preparation for the next shear bending processing.

[0046] (6) Control device 16 The control device 16 controls the various operations of the above-described feeding device 11, support device 12, heating device 13, cooling device 14, and shear force applying device 15. When a sliding type or the like that does not require operation control is used as the support device 12, the support device 12 is excluded from the control targets. The control device 16 controls the feeding amount and feeding speed of the hollow material Pm by giving an instruction to the feeding device 11. On the other hand, when the feeding device 11 is omitted and the feeding function is provided to the support device 12, the control device 16 gives an instruction to the support device 12 to control the rotation amount and rotation speed of the rolls 12a and 12b. Thereby, the feeding amount and feeding speed of the hollow material Pm are controlled. The control device 16 controls the temperature of the heated portion H by controlling the power output flowing through the heating coil 13a. The control device 16 may control the heating coil 13a to be inclined with respect to the hollow material Pm as necessary. The control device 16 controls the temperature of the cooled portion by controlling the supply pressure or supply flow rate of the cooling water supplied to each cooling water injection nozzle 14a. The control device 16 may control each cooling water injection nozzle 14a to be inclined with respect to the hollow material Pm as necessary. The control device 16 individually controls each of the arms 15A and 15B. That is, the control device 16 controls the position and inclination of each of the gripping means 15Aa, 15Ab, 15Ba, and 15Bb by controlling the arm portion 15Ac. Further, the control device 16 controls the opening and closing operations (gripping state and gripping release state) of each of the gripping means 15Aa, 15Ab, 15Ba, and 15Bb. The above is an example of the control device 16. When mass-producing the same hollow bent component Pp, it is also possible to set the control amount in a predetermined pattern in advance.

[0047] [Manufacturing method of hollow bent member] A method for manufacturing the hollow bent member Pp from the hollow material Pm using the above manufacturing apparatus 10 will be described below with reference to FIG. 2. In this embodiment, the case of manufacturing the hollow bent part Pp in Fig. 2(f) from the hollow material Pm in Fig. 2(a) using the manufacturing apparatus 10 will be described. This hollow bent member Pp has a shearing and bending process applied to one location in its longitudinal direction. Note that in Fig. 2, the control apparatus 16 and the arm part 15Bc are not shown.

[0048] As shown in Fig. 2(a), first, the hollow material Pm, which is a straight hollow tube made of metal, is set in the manufacturing apparatus 10. That is, the hollow material Pm is supported by the support apparatus 12 at the first position A, the rear end side of the hollow material Pm is set in the feeding apparatus 11, and the front end side of the hollow material Pm is gripped by the gripping means 15Ba and 15Bb. On the other hand, since the gripping means 15Aa and 15Ab are in a standby state, their illustration is omitted in Fig. 2(a). At this time, the heating coil 13a of the heating apparatus 13 is arranged at the second position B downstream from the first position A, and each cooling water injection nozzle 14a of the cooling apparatus 14 is arranged at the third position C downstream from the second position B. Also, the heating coil 13a and each cooling water injection nozzle 14a are arranged in a state orthogonal to the central axis CL in both side view and plan view. Based on the above settings, the heating of the hollow material Pm by the heating apparatus 13 is started.

[0049] That is, as shown in Figs. 2(a) and 2(b), while supporting the hollow material Pm at the first position A, the hollow material Pm is fed in the feeding direction F, which is the longitudinal direction of the hollow material Pm (feeding process), the hollow material Pm is partially heated at the second position B to form the heated part H (heating process), and at least a part of the hollow material Pm located on the downstream side of the heated part H is cooled at the third position C (cooling process). At this time, the gripping means 15Ba and 15Bb move in the feeding direction F in synchronization with the feeding speed of the hollow material Pm. Therefore, the hollow material Pm is quenched while remaining a straight tube without undergoing shearing and bending or normal bending and is fed in the feeding direction F.

[0050] Subsequently, as shown in Fig. 2(c), when the hollow material Pm reaches the position where the shearing and bending process is to be performed, the gripping means 15Aa and 15Ab that have been in the standby state are moved to the fourth position D1, and the middle position in the longitudinal direction of the hollow material Pm is gripped at this position. At this time, the control device 16 controls the gripping position so as to limit the distance L' parallel to the feeding direction F between the most downstream position P0 along the feeding direction F where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 within a predetermined distance.

[0051] During the period from the start to the end of the shearing and bending process, the control device 16 controls the gripping means 15Aa, 15Ab and the arm portion 15Ac, so that the distance L' continues to be adjusted within the predetermined distance. When the average width dimension of the hollow material Pm before the shearing and bending process is w (mm), it is preferable to set the predetermined distance to 20 × w (mm) or less, preferably 10 × w (mm) or less. In this case, the distance between the heated portion H and the gripping means 15Aa, 15Ab is appropriately shortened to effectively suppress the deflection of the hollow material Pm at this portion, and then the shearing and bending process can be performed. Alternatively, the predetermined distance may be set based on the shearing load of the hollow material Pm. In this case, the deflection can be more effectively suppressed according to the shape and material of the hollow material Pm.

[0052] After the gripping means 15Aa and 15Ab grip the hollow material Pm at the fourth position D1, the gripping means 15Ba and 15Bb at the fifth position D2 are opened to release the grip. After the grip is released, the gripping means 15Ba and 15Bb are moved so as not to interfere with the hollow material Pm and enter the standby state. Therefore, in Figs. 2(d) to 2(f), the illustration of the gripping means 15Ba and 15Bb in the standby state is omitted.

[0053] As shown in Fig. 2(d), the gripping position of the hollow material Pm at the fourth position D1 is moved in a two-dimensional or three-dimensional direction by the arm portion 15Ac (shearing and bending process). Specifically, in the shearing process, the gripping position is moved in an inclined direction between the feeding direction F along the longitudinal direction of the hollow material Pm and the direction orthogonal to the longitudinal direction of the hollow material Pm when viewed in a cross-section including the central axis CL of the hollow material Pm.

[0054] At this time, the shearing and bending process location is cooled by the cooling water from each cooling water injection nozzle 14a, so quenching is also performed simultaneously. During the period from the start to the end of the shearing and bending process, the distance L' is restricted within a predetermined distance by the control device 16. In this way, by gripping the hollow material Pm at a position close to its heated portion H and performing shearing and bending processing, the point of application of the force applied by the gripping means 15Aa, 15Ab is closer to the point of application that undergoes shearing and bending in the hollow material Pm, and the deflection corresponding to the distance between these point of application and the point of action is reduced. As a result, compared with the case of gripping and shearing and bending the hollow material Pm at its downstream end as in the prior art, the distance between the heated portion H and the gripping means 15Aa, 15Ab is shortened to suppress the deflection of the hollow material Pm in this portion, and then shearing and bending processing can be performed. Therefore, the processing accuracy of the manufactured hollow bent part Pp is improved.

[0055] After the shearing and bending process is completed, as shown in Fig. 2(e), the gripping means 15Aa, 15Ab are moved in the feeding direction F while keeping the hollow material Pm gripped and synchronizing the position with the feeding operation of the feeding device 11. Thereby, quenching is performed in the range upstream of the location where the shearing and bending process is applied to the hollow material Pm. When the quenching of the hollow material Pm is completed to the end, as shown in Fig. 2(f), the heating by the heating coil 13a is stopped, and the processed hollow bent part Pp is removed from the manufacturing device 10 and discharged. As described above, the hollow bent part Pp is manufactured by a series of processes including a feeding process, a heating process, a cooling process, and a shear bending process. During the shear bending process from the start to the end, the hollow bent part Pp restricts the distance L' parallel to the feeding direction F between the most downstream position P0 and the gripping position P2 along the feeding direction F where the roll 12a of the support device 12 contacts the hollow member Pm within the predetermined distance, so that it has less deflection and high processing accuracy.

[0056] [Second Embodiment] Subsequently, with reference to FIGS. 3 to 5, a manufacturing apparatus and a manufacturing method for a hollow bent part according to the second embodiment will be described below.

[0057] [Manufacturing Apparatus for Hollow Bent Member] The manufacturing apparatus for a hollow bent member according to the present embodiment (hereinafter, manufacturing apparatus 20) differs only in the configuration of the shearing force applying device 15 compared to the manufacturing apparatus 10 of the first embodiment. Therefore, for other components, the same part numbers as those of the manufacturing apparatus 10 are used, and redundant descriptions thereof are omitted. As shown in FIG. 3, this manufacturing apparatus 20 includes the feeding device (feeding section) 11, the support device (support means) 12, the heating device 13, the cooling device (cooling section) 14, a shearing force applying device 25, and the control device (control section) 16.

[0058] The shearing force applying device 25 of the present embodiment is arranged at a fourth position D downstream of a third position C along the feeding direction F of the hollow material Pm. The shearing force applying device 25 grips the intermediate position of the hollow material Pm in the longitudinal direction and moves this gripping position in the two-dimensional or three-dimensional direction. Specifically, the gripping position of the hollow material Pm in the shearing force applying device 25 is moved in an inclined direction between the feeding direction F along the longitudinal direction of the hollow material Pm and the direction orthogonal to the longitudinal direction of the hollow material Pm as viewed in the cross-section including the central axis CL. Thereby, the shearing force applying device 25 applies a shearing force to at least a part of the region between the heated portion H heated by the heating device 13 and the cooled portion cooled by the cooling device 14 in the hollow material Pm to perform a shear bending process on the hollow material Pm.

[0059] As shown in FIGS. 3 and 4, the shearing force applying device 25 includes gripping means 25A and 25B that grip the hollow material Pm at a fourth position D downstream of a third position C along the feeding direction F of the hollow material Pm, an arm portion (operating portion) 25C that supports the gripping means 25A and 25B and moves its position in the two-dimensional or three-dimensional direction, and a base (not shown) that supports the arm portion 25C. Note that a plurality of sets of the gripping means 25A and 25B and the arm portion 25C may be provided.

[0060] As shown in FIG. 4, the gripping means 25A includes a main body 25Aa, a pair of support rollers 25Ab, a pair of clamps 25Ac, and a drive mechanism (not shown). The main body 25Aa is a long housing along the longitudinal direction of the hollow material Pm, and houses each support roller 25Ab, each clamp 25Ac, and the drive mechanism. A semi-cylindrical recess a for passing the hollow material Pm is formed at the lower portion of the main body 25Aa. The pair of support rollers 25Ab are respectively rotatably arranged at the central position in the longitudinal direction of the main body 25Aa. Each support roller 25Ab is supported in a state of protruding into the recess a of the main body 25Aa. A pair of clampers 25Ac are arranged at both longitudinal ends of the main body 25Aa with a pair of support rollers 25Ab interposed therebetween. Each clamper 25Ac is supported within the main body 25Aa so as to be able to approach and separate from the outer peripheral surface of the hollow material Pm. Each clamper 25Ac can enter and exit the inside and outside of the recess a of the main body 25Aa by receiving the force of the drive mechanism. The drive mechanism operates in response to an instruction from the control device 16. Specifically, the drive mechanism switches between a state in which each clamper 25Ac protrudes from each support roller 25Ab within the recess a and a state in which each clamper 25Ac is housed within the main body 25Aa. When each clamper 25Ac is housed within the main body 25Aa, each support roller 25Ab is in rolling contact with the outer peripheral surface of the hollow material Pm in a freely rotatable manner. Conversely, when each clamper 25Ac protrudes from each support roller 25Ab within the recess a, these clampers 25Ac are in non-relative-movement contact with the outer peripheral surface of the hollow material Pm. As the drive source of the drive mechanism, for example, fluid pressure (hydraulic pressure, pneumatic pressure) can be utilized.

[0061] The gripping means 25B also has the same configuration as the gripping means 25A. That is, the gripping means 25B includes a main body 25Ba, a pair of support rollers 25Bb, a pair of clampers 25Bc, and another drive mechanism (not shown). The main body 25Ba is a long housing along the longitudinal direction of the hollow material Pm and has the same shape and dimensions as the main body 25Aa. The main body 25Ba houses each support roller 25Bb, each clamper 25Bc, and the other drive mechanism. A semi-cylindrical recess b for passing the hollow material Pm is formed at the upper part of the main body 25Ba. A pair of support rollers 25Bb are rotatably arranged at the central position in the longitudinal direction of the main body 25Ba. Each support roller 25Bb is supported by the other drive mechanism so as to be able to enter and exit the inside and outside of the recess b of the main body 25Ba. A pair of clampers 25Bc are arranged at both longitudinal ends of the main body 25Ba with a pair of support rollers 25Bb interposed therebetween. Each clamper 25Bc is supported within the main body 25Ba so as to be able to approach and separate from the outer peripheral surface of the hollow material Pm. Each clamper 25Bc can enter and exit the inside and outside of the recess b of the main body 25Ba by receiving the force of the drive mechanism. The other drive mechanism operates in response to an instruction from the control device 16. Specifically, the other drive mechanism switches between a state where each clamper 25Bc protrudes from each support roller 25Bb within the recess b and a state where each clamper 25Bc is housed within the main body 25Ba. When each clamper 25Bc is housed within the main body 25Ba, each support roller 25Bb is in rolling contact with the outer peripheral surface of the hollow material Pm. Conversely, when each clamper 25Bc protrudes from each support roller 25Bb within the recess b, these clampers 25Bc are in non-relative movement contact with the outer peripheral surface of the hollow material Pm. As the drive source of the drive mechanism, for example, fluid pressure (hydraulic pressure, pneumatic pressure) can be utilized.

[0062] The gripping means 25A and 25B having the above configuration are supported by the arm portion 25C in a state where the recesses a and b face each other. And the hollow material Pm can be inserted into the cylindrical space formed by the recesses a and b. With the hollow material Pm inserted between the gripping means 25A and 25B, by housing each clamper 25Ac and each clamper 25Bc within the main body 25Aa and the main body 25Ba by the drive mechanism and the other drive mechanism, the hollow material Pm can be gripped movably along its longitudinal direction between each support roller 25Ab and each support roller 25Bb. Although each support roller 25Ab and each support roller 25Bb of the present embodiment are driven rollers, when a configuration is adopted in which they are rotated by a motor (not shown) in accordance with the feed amount of the hollow material Pm, the surface quality of the hollow material Pm can be improved. On one hand, with the hollow material Pm inserted between the gripping means 25A and 25B, when each clamp 25Ac and each clamp 25Bc are protruded from each support roller 25Ab and each support roller 25Bb within the recesses a and b by the drive mechanism and the other drive mechanism, the hollow material Pm can be gripped between each clamp 25Ac and each clamp 25Bc so as not to be movable along its longitudinal direction.

[0063] Therefore, the gripping means 25A and 25B are configured to be switchable between a first gripping state that allows relative movement of the hollow material Pm along its longitudinal direction with respect to these gripping means 25A and 25B, and a second gripping state that restricts relative movement of the hollow material Pm along its longitudinal direction with respect to these gripping means 25A and 25B. And the control device 16 enables the gripping means 25A and 25B to be switched between the first gripping state and the second gripping state. When not applying shear bending processing to the hollow material Pm, after setting the gripping means 25A and 25B to the first gripping state, they are fixedly arranged at a fixed position. Thereby, the hollow material Pm can be supported so as to be movable along the feed direction F without moving the gripping means 25A and 25B. On the other hand, when applying shear bending processing to the hollow material Pm, after setting the gripping means 25A and 25B to the second gripping state, the gripping position is moved in a two-dimensional direction or a three-dimensional direction by the arm portion 25C. As a result, shear bending processing is applied to the hollow material Pm.

[0064] As shown in FIG. 3, when the gripping means 25A and 25B are set to the second gripping state, the longitudinal center position of the support range where each clamp 25Ac and each clamp 25Bc contact the hollow material Pm is defined as the gripping position P2. And the distance parallel to the feed direction F between the most downstream position P0 where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 is shown in FIG. 3 as L'. This distance L' is maintained within a predetermined distance by the arm portion 25C adjusting the position of the gripping means 25A and 25B upon receiving an instruction from the control device 16 during shear bending processing.

[0065] At a fourth position D downstream of a third position C along the feeding direction F of the hollow material Pm, by moving the positions of the pair of gripping means 25A and 25B in a two-dimensional or three-dimensional direction, a shearing force can be applied to a region between a heated portion H heated by the heating device 13 and a cooled portion cooled by the cooling device 14 in the hollow material Pm. When the shearing force acts on the hollow material Pm, the middle position in its longitudinal direction bends as shown in FIG. 3. In this embodiment, the arm portion 25C is used to move the positions of the gripping means 25A and 25B. Instead, a combination of a ball screw and a servo motor may be employed.

[0066] [Method for manufacturing a hollow bent member] A method for manufacturing the hollow bent member Pp from the hollow material Pm using the above manufacturing apparatus 20 will be described below with reference to FIG. 5. In this embodiment, a case of manufacturing the hollow bent member Pp in FIG. 5(f) from the hollow material Pm in FIG. 5(a) using the manufacturing apparatus 20 will be described. The hollow bent member Pp has a shear bending process applied at one location in its longitudinal direction. In FIG. 5, the illustration of the control device 16 and the arm portion 25C is omitted.

[0067] As shown in FIG. 5(a), first, the hollow material Pm, which is a straight hollow tube made of metal, is set in the manufacturing apparatus 20. That is, the hollow material Pm is supported by the support device 12 at the first position A, the rear end side of the hollow material Pm is fixed to the feeding device 11, and the front end side of the hollow material Pm is gripped by the gripping means 25A and 25B. In the gripping means 25A and 25B at this time, since each clamp 25Ac and each clamp 25Bc are housed in the main bodies 25Aa and 25Ba, each clamp 25Ac and each clamp 25Bc are in a non-contact state with respect to the outer peripheral surface of the hollow material Pm. On the other hand, each support roller 25Ab and each support roller 25Bb are in contact with the outer peripheral surface of the hollow material Pm to support the hollow material Pm. Therefore, with the gripping means 25A and 25B fixed in a fixed position, it is possible to feed the hollow material Pm along the feeding direction F. Further, arrange the heating coil 13a of the heating device 13 at the second position B downstream of the first position A, and arrange each cooling water injection nozzle 14a of the cooling device 14 at the third position C downstream of the second position B. Also, the heating coil 13a and each cooling water injection nozzle 14a are arranged in a state orthogonal to the central axis CL in both side view and plan view. Under the above settings, start heating the hollow material Pm by the heating device 13.

[0068] That is, as shown in FIGS. 5(a) and 5(b), while supporting the hollow material Pm at the first position A, the hollow material Pm is fed in the feed direction F which is the longitudinal direction of the hollow material Pm (feeding step), and the hollow material Pm is partially heated at the second position B to form a heated portion H (heating step), and at least a part of the hollow material Pm located on the downstream side of the heated portion H is cooled at the third position C (cooling step). Also at this time, only each support roller 25Ab and each support roller 25Bb support the outer peripheral surface of the hollow material Pm. Therefore, with the gripping means 25A and 25B fixed in place, the hollow material Pm can be fed along the feed direction F while restricting movement in the direction orthogonal to the central axis CL.

[0069] Subsequently, as shown in FIG. 5(c), when the hollow material Pm reaches the position where the shearing and bending process is to be performed, each clamp 25Ac and each clamp 25Bc are protruded into the recesses a and b. As a result, each clamp 25Ac and each clamp 25Bc contact the outer peripheral surface of the hollow material Pm, and each support roller 25Ab and each support roller 25Bb are separated from the outer peripheral surface of the hollow material Pm. Thus, each clamp 25Ac and each clamp 25Bc support the hollow material Pm instead of each support roller 25Ab and each support roller 25Bb. In this way, before the start of the shearing and bending process, the gripping means 25A and 25B are switched from the first gripping state that grips while allowing movement along the longitudinal direction of the hollow material Pm to the second gripping state that restricts movement along the longitudinal direction of the hollow material Pm. Note that the point of restricting the movement of the hollow material Pm in the direction orthogonal to the central axis CL is the same in both the first gripping state and the second gripping state.

[0070] As shown in FIG. 5(c), when the hollow material Pm is supported by each clamp 25Ac and each clamp 25Bc, the control device 16 controls the gripping position P2 so as to limit the distance L' parallel to the feed direction F between the most downstream position P0 along the feed direction F where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 within a predetermined distance. Then, during the start to end of the shear bending process, the control device 16 controls the gripping means 25A, 25B and the arm portion 25C, and the distance L' continues to be adjusted within the predetermined distance. When the average width dimension of the hollow material Pm before performing the shear bending process is w (mm), it is preferable to set the predetermined distance to 20×w (mm) or less, preferably 10×w (mm) or less. In this case, the distance between the heated portion H and each clamp 25Ac and each clamp 25Bc is appropriately shortened, and the shear bending process can be performed after effectively suppressing the deflection of the hollow material Pm in this portion. Alternatively, the predetermined distance may be set based on the shear load of the hollow material Pm. In this case, the deflection can be more effectively suppressed according to the shape and material of the hollow material Pm.

[0071] As shown in FIG. 5(d), at the fourth position D, the gripping position P2 of the hollow material Pm is moved in the two-dimensional direction or the three-dimensional direction by the arm portion 25C (shear bending process). Specifically, in the shearing process, the gripping position P2 is moved in an inclined direction between the feed direction F along the longitudinal direction of the hollow material Pm and the direction orthogonal to the longitudinal direction of the hollow material Pm as viewed in a cross section including the central axis CL of the hollow material Pm.

[0072] At this time, the shearing and bending process section is cooled by the cooling water from each cooling water injection nozzle 14a, so quenching is also performed simultaneously. During the period from the start to the end of the shearing and bending process, the distance L’ is restricted within a predetermined distance by the control device 16. In this way, by gripping and shearing and bending the hollow material Pm at a position close to its heated portion H, the force application points of the forces applied by the gripping means 25A and 25B are close to the action points that undergo shearing and bending in the hollow material Pm, and the deflection corresponding to the distance between these force application points and action points is reduced. As a result, compared with the case of gripping and shearing and bending the hollow material Pm at its downstream end as in the prior art, the distance between the heated portion H and the gripping means 15Aa and 15Ab is shortened to suppress the deflection of the hollow material Pm in this portion, and then the shearing and bending process can be performed. Therefore, the processing accuracy of the manufactured hollow bent part Pp is improved.

[0073] After the shearing and bending process is completed, as shown in Fig. 5(e), the gripping means 25A and 25B are moved in the feed direction F while keeping the hollow material Pm gripped and synchronizing their positions with the feed operation of the feed device 11. Thereby, quenching is performed in a range upstream of the portion of the hollow material Pm where the shearing and bending process is applied. When the quenching of the hollow material Pm is completed to the end, as shown in Fig. 5(f), the heating by the heating coil 13a is stopped, and the processed hollow bent part Pp is removed from the manufacturing device 20 and discharged. As described above, the hollow bent part Pp is manufactured by a series of processes including a feeding process, a heating process, a cooling process, and a shearing and bending process. During the period from the start to the end of the shearing and bending process, the hollow bent part Pp restricts the distance L’ parallel to the feed direction F between the most downstream position P0 along the feed direction F where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 within the predetermined distance, so it has less deflection and high processing accuracy.

[0074] [Third Embodiment] Next, while referring to FIG. 6, a method for manufacturing a hollow bent component according to the third embodiment will be described below. Since the apparatus configuration is the same as that of the manufacturing apparatus 10 described in the first embodiment above, duplicate description will be omitted by using the same part numbers as those shown in FIG. 1.

[0075] [Method for manufacturing a hollow bent member] In this embodiment, a case where the hollow bent component Pp shown in FIG. 6(f) is manufactured from the hollow material Pm shown in FIG. 6(a) using the manufacturing apparatus 10 will be described. The hollow bent member Pp has shear bending processes applied at two locations in its longitudinal direction. Note that in FIG. 6, the control device 16 and the arm portion 15Bc are not shown.

[0076] As shown in FIGS. 6(a) and 6(b), while gripping the tip of the hollow material Pm with the gripping means 15Ba and 15Bb, first, the first shear bending process is performed. This first shear bending process is performed, for example, by performing the steps described in FIG. 2. Therefore, during the period from the start to the end of the shear bending process, the distance L' is set within the predetermined distance by the control device 16. Even after the shear bending process is completed as shown in FIG. 6(b), quenching is continued. That is, while supporting the hollow material Pm at the first position A and feeding it in the feeding direction F, which is the longitudinal direction of the hollow material Pm (feeding step), the hollow material Pm is partially heated at the second position B to form the heated portion H (heating step), and at least a part of the hollow material Pm located downstream of the heated portion H is cooled at the third position C (cooling step). At this time, the gripping means 15Ba and 15Bb are moved in the feeding direction F in synchronization with the feeding speed of the hollow material Pm. Therefore, the range upstream of the portion where the first shear bending process is applied in the hollow material Pm is quenched while being fed in the feeding direction F without undergoing shear bending or normal bending and remaining as a straight pipe.

[0077] Subsequently, as shown in FIG. 6(c), when the hollow material Pm reaches the position where the second shearing and bending process is to be performed, the gripping means 15Aa and 15Ab in the standby state are moved to the first position A. Then, as shown in FIG. 6(d), the middle position in the longitudinal direction of the hollow material Pm is gripped at the first position A. At this time, the control device 16 controls the arm portion 15Ac so as to limit the distance L' parallel to the feeding direction F between the most downstream position P0 along the feeding direction F where the roll 12a of the support device 12 contacts the hollow member Pm and the gripping position P2 within the predetermined distance. After the hollow material Pm is appropriately gripped by the gripping means 15Aa and 15Ab, the gripping of the hollow material Pm is released by opening the gripping means 15Ba and 15Bb that were gripping the tip of the hollow material Pm at the fifth position D2. In this way, from FIG. 6(c) to FIG. 6(d), the gripping position of the hollow material Pm is switched from the fifth position D2 to the fourth position D1. The released gripping means 15Ba and 15Bb are moved so as not to interfere with the hollow material Pm or the like and enter the standby state. Therefore, in FIGS. 6(e) and 6(f), the illustration of the standby gripping means 15Ba and 15Bb is omitted.

[0078] Then, as shown in FIGS. 6(e) and 6(f), the second shearing and bending process is performed. Since the shearing and bending process location at this time is also cooled by the cooling water from each cooling water injection nozzle 14a, quenching is performed simultaneously. During the period from the start to the end of the shearing and bending process, the distance L' is restricted within the predetermined distance by the control device 16. Therefore, the distance between the heated portion H and the gripping means 15Aa and 15Ab is shortened to suppress the deflection of the hollow material Pm in this portion, and then the shearing and bending process can be performed.

[0079] When the shearing and bending process is completed to the end, as shown in FIG. 6(f), the heating by the heating coil 13a is stopped, and the processed hollow bent part Pp is removed from the manufacturing apparatus 10 and discharged. As described above, a hollow bent part Pp is manufactured by a series of processes including a feeding process, a heating process, a cooling process, and a shear bending process. In this hollow bent part Pp, at two shear bending locations, during the period from the start to the end of the shear bending process, the roll 12a of the support device 12 is in contact with the hollow member Pm, and the distance L' parallel to the feeding direction F between the most downstream position P0 and the gripping position P2 along the feeding direction F is limited within the predetermined distance. Therefore, the hollow bent part Pp has high processing accuracy with little deflection. Each of the above-described embodiments was an explanation of the case where only hot shear bending is performed. However, it is also possible to manufacture the hollow bent part Pp by combining this shear bending process with, for example, the conventional hot bending process shown in FIG. 7.

Example

[0080] An example of a manufacturing method using a manufacturing apparatus for a hollow bent part will be described below. In this example, a plurality of hollow bent parts Pp made of 0.2% carbon steel with a height H = 20 mm, a width w = 20 mm, a plate thickness t = 1.0 mm, and a total length TL = 2000 mm were manufactured. The manufacturing method when each hollow bent part Pp was manufactured is as shown in Table 1 below using the corresponding drawing numbers. Also, the maximum temperature reached in the heated part H was all set to 950°C. The distance L' was as shown in Table 1. For each of the manufactured hollow bent parts Pp, the dimensional error from the target product dimensions was measured. Then, those with a dimensional error in the range of -0.5 mm to +0.5 mm were set as good products, and those outside the range were set as defective products, and the ratio of the number of defective products to the total number was calculated. As shown in Table 1, as in Examples 1 to 5 of the present invention, it was confirmed that the defective rate could be reduced compared to the conventional example under all conditions. In particular, good results were obtained when L' / w < 20 (i.e., L' < 20 × w). Furthermore, significantly good results were obtained when L' / w < 10 (i.e., L' < 10 × w).

[0081]

Table 1

[0082] The hollow bent member Pp manufactured by the manufacturing method according to the present invention is applicable to, for example, the following uses (i) to (vii). (i) Structural members of an automobile body such as, for example, a front side member, a cross member, a side member, a suspension member, a roof member, a rain reinforcement of an A-pillar, a rain reinforcement of a B-pillar, a rain reinforcement of a bumper, etc. (ii) Strength members and reinforcing members of an automobile such as, for example, a seat frame, a seat cross member, etc. (iii) Exhaust system parts such as an exhaust pipe of an automobile (iv) Frames and cranks of bicycles and motorcycles (v) Reinforcing members and bogie parts (bogie frames, various beams, etc.) of vehicles such as trains (vi) Frame parts and reinforcing members of a ship's hull, etc. (vii) Strength members, reinforcing members or structural members of home appliances

Explanation of reference numerals

[0083] 10, 20 Manufacturing apparatus for hollow bent parts 11 Feeding device (feeding section) 12 Supporting device (supporting means) 13a Heating coil 14 Cooling device (cooling section) 15Aa, 15Ab, 15Ba, 15Bb, 25A, 25B Gripping means 15Ac, 15Bc, 25C Arm part (operating section) 16 Control device (control section) 25Ab, 25Bb Support rollers (rollers) 25Ac, 25Bc Clamps D, D1 Gripping positions F Feeding direction H Heated portion L’ Distance P0 Most downstream end position P2 Longitudinal center position (gripping position) of the range where the gripping means contacts the hollow material Pm Hollow material (workpiece) Pp Hollow Buckling Component

Claims

1. A feeding section for moving a metal workpiece that is hollow in the longitudinal direction thereof; Support means for supporting the workpiece in a state where movement in a direction orthogonal to the longitudinal direction is restricted and movement in the feeding direction along the longitudinal direction is allowed; A heating coil disposed so as to surround the workpiece on the downstream side in the feeding direction from the support means for heating the workpiece; A cooling section for cooling the workpiece on the downstream side in the feeding direction from the heating coil; Gripping means for gripping the workpiece at a gripping position on the downstream side in the feeding direction from the cooling section; An operating section for moving the gripping means; A control section for controlling the feeding section, the heating coil, the cooling section, the gripping means, and the operating section; Comprising: An apparatus for applying a shear bending process to the workpiece by moving the gripping means in a two-dimensional or three-dimensional direction by the operating section, wherein the control section During the period from the start to the end of the shear bending process, Restricts the distance from the most downstream end position along the feeding direction of the support range of the workpiece by the support means to the central position along the feeding direction of the support range of the workpiece by the gripping means within a predetermined distance, Controls the gripping means and the operating section A manufacturing apparatus for hollow bent parts, characterized in that.

2. When the average width dimension of the workpiece before performing the shear bending process is w (mm), the predetermined distance is set to 20 × w (mm) or less The manufacturing apparatus for hollow bent parts according to claim 1, characterized in that.

3. The gripping means A first gripping state that allows relative movement of the workpiece along the longitudinal direction with respect to the gripping means, A second gripping state that restricts relative movement of the workpiece along the longitudinal direction with respect to the gripping means, Is configured to be switchable between, The control section switches between the first gripping state and the second gripping state of the gripping means, The manufacturing apparatus for hollow bent parts according to claim 1 or 2, characterized in that.

4. The gripping means A roller configured to be able to approach and separate from the outer peripheral surface of the workpiece and to be in rolling contact with the outer peripheral surface of the workpiece in the first gripping state, A clamper configured to be able to approach and separate from the outer peripheral surface and to be in contact with the outer peripheral surface of the workpiece in the second gripping state, Comprising The manufacturing apparatus for hollow bent parts according to claim 3, characterized in that.

5. The manufacturing apparatus for a hollow bent component according to any one of claims 1 to 4, characterized by having a plurality of the gripping means and the operation units respectively.

6. A feeding step of supporting a metal workpiece that is hollow while restricting movement in a direction orthogonal to the longitudinal direction and feeding it in a feeding direction along the longitudinal direction at a support position in the middle of the longitudinal direction; A heating step of partially heating the workpiece to form a heated portion by a heating coil arranged so as to surround the periphery of the workpiece at a heating position downstream of the support position; A cooling step of cooling the workpiece at a cooling position downstream of the heating position; A shearing and bending process step of gripping a gripped portion of the workpiece by gripping means at a gripping position downstream of the cooling position, and moving the gripping means in a two-dimensional direction or a three-dimensional direction to apply a shearing and bending process to the workpiece; having; During the period from the start to the end of the shearing and bending process, limiting the distance from the most downstream end position along the feeding direction of the support range of the workpiece at the support position to the central position along the feeding direction of the gripped portion at the gripping position within a predetermined distance. A method for manufacturing a hollow bent component, characterized by the above.

7. When the average width dimension of the workpiece before performing the shearing and bending process is w (mm), setting the predetermined distance to 20 × w (mm) or less. A method for manufacturing a hollow bent component according to claim 6, characterized by the above.

8. Setting the predetermined distance based on the shearing load of the workpiece. A method for manufacturing a hollow bent component according to claim 6, characterized by the above.

9. Before the start of the shearing and bending process step, switching the gripping means from a first gripping state that allows movement along the longitudinal direction of the workpiece while gripping to a second gripping state that restricts movement along the longitudinal direction of the workpiece. A method for manufacturing a hollow bent component according to any one of claims 6 to 8, characterized by the above.

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