Coiling machine and method for manufacturing coil springs

Abstract

To improve manufacturing efficiency of a coil spring and improve efficiency in a layout of various elements for coil spring manufacturing.SOLUTION: A coiling machine includes: a transportation unit for transporting a wire in a transportation direction; a spiral forming unit for forming a coil spring extending spirally toward a forming direction by sequentially bending the wire transported by the transportation unit in a vertical direction; a laser heating machine for heating part of the wire by radiating a laser beam to the wire bent by the spiral forming unit; and a cut-off unit for cutting off the portion of the wire heated by the laser beam. When a forming direction is 0°, an opposite side in the transportation direction is 90°, an opposite side in the forming direction is 180°, and the transportation direction is 270°with a laser beam irradiation region in the wire as a reference, an irradiation direction of the laser beam by the laser heating machine forms a first angle of 0-270°.SELECTED DRAWING: Figure 15

Description

Technical Field

[0001] The present invention relates to a coiling machine for manufacturing a coil spring and a method for manufacturing a coil spring.

Background Art

[0002] As an apparatus for manufacturing a coil spring, for example, a coil spring forming machine described in Patent Document 1 is known. This coil spring forming machine calculates in advance the position of a cutting site based on the length of a wire to be formed into a spiral shape, and cuts the wire in a state where the cutting site is softened by high-frequency heating.

[0003] On the other hand, a coiling machine that cuts a wire formed into a spiral shape with a laser beam, such as the spring manufacturing apparatus described in Patent Document 2, is also known.

[0004] When high-frequency heating is used as in the coil spring forming machine of Patent Document 1, the responsiveness of heating of the cutting site is not good. Moreover, in this coil spring forming machine, since the wire is cut while the heating of the cutting site by high-frequency heating continues, the members used for cutting may be affected by high-frequency heating. Further, in this coil spring forming machine, since the responsiveness of high-frequency heating is not sufficient and the wire is coiled in a state where the wire is partially heated, there is a risk that it becomes difficult to maintain the forming accuracy of the spring constant.

[0005] On the other hand, in the spring manufacturing apparatus of Patent Document 2, a high-output laser beam capable of cutting a wire is required. In this case, sputtering may occur due to the irradiation of the laser beam, and since the laser beam can be irradiated not only to the wire but also to each part of the spring manufacturing apparatus, countermeasures must be taken.

[0006] In response to this, the applicant of the present application proposes a method, as described in Patent Document 3, of cutting a portion of a wire heated by laser light with a cutting tool such as a cutter. This method makes it possible to easily cut the wire and obtain a coil spring with a good cut surface. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 62-50028 [Patent Document 2] Japanese Patent Application Publication No. 6-218476 [Patent Document 3] Patent No. 7066880 [Overview of the project] [Problems that the invention aims to solve]

[0008] As mentioned above, there is room for various improvements in the method of cutting a wire heated by laser light with a cutting tool. For example, the direction of laser beam irradiation relative to the irradiation position of the wire needs to be appropriately determined considering the heating efficiency and interference with various components.

[0009] One of the objectives of this invention is to provide a coiling machine and a method for manufacturing coil springs that can improve the manufacturing efficiency of coil springs and optimize the layout of various elements for manufacturing coil springs. [Means for solving the problem]

[0010] The coiling machine according to the present invention comprises: a conveying unit that conveys a wire in a conveying direction; a spiral forming unit that sequentially bends the wire conveyed by the conveying unit in a vertical direction perpendicular to the conveying direction to form a coil spring that extends spirally in a forming direction perpendicular to the conveying direction and the vertical direction; a laser heating machine that heats a portion of the wire by irradiating the wire bent by the spiral forming unit with laser light; and a cutting unit that cuts the portion of the wire heated by the laser light. A main body located on the opposite side of the molding direction from the conveying unit, the helical forming unit, and the cutting unit, and which supplies power to the conveying unit, the helical forming unit, and the cutting unit, It is equipped with. The helical forming unit comprises a forming roller that sequentially bends the wire, which is conveyed in the conveying direction by the conveying unit, in the vertical direction, and a pitch tool that guides the bent wire at a position offset from the forming roller in the forming direction. The cutting unit comprises a mandrel that supports the inner circumferential surface of the wire bent by the forming roller, and a cutter that cuts the wire by applying an impact to the outer circumferential surface of the wire protruding from the end of the mandrel. Furthermore, the irradiation center of the laser beam on the outer circumferential surface of the wire is at a position offset from the end of the mandrel in the opposite direction of the conveying direction.

[0011] Furthermore, the method for manufacturing a coil spring according to the present invention includes: conveying a wire in a conveying direction; sequentially bending the conveyed wire in a vertical direction perpendicular to the conveying direction to form a coil spring that extends spirally in a forming direction perpendicular to the conveying direction and the vertical direction; heating a part of the bent wire by irradiating it with laser light; and cutting the part of the wire that has been heated by the laser light.

[0012] According to one aspect of the present invention, when the irradiation area of ​​the laser light on the wire is set to 0° in the molding direction, 90° on the opposite side of the transport direction, 180° on the opposite side of the molding direction, and 270° in the transport direction, The molding roller is located in the range of 180° to 270°, and the pitch tool is located around 90°. Direction of irradiation of the laser light by the laser heating machine but The molding direction and 0° or more and 80 Forming a first angle of less than or equal to ° This configuration avoids interference between the laser beam and the main body, the molding roller, the pitch tool, and the cutter. .

[0013] According to another aspect of the present invention, The wire formed spirally by the helical forming unit includes a zero-turn portion that contacts the forming roller, the pitch tool, and the mandrel, and a first-turn portion adjacent to the zero-turn portion in the forming direction and not in contact with the forming roller, the pitch tool, and the mandrel, wherein the outer diameter of the first-turn portion is larger than the outer diameter of the first-turn portion, and the laser heater irradiates the zero-turn portion with the laser light. Furthermore, With the irradiation area of ​​the laser beam on the wire as the reference, and the vertical direction set to 0° and the molding direction set to 90°, the irradiation direction of the laser beam by the laser heating machine but A second angle with respect to the aforementioned vertical direction that is 5° or more and 80° or less This configuration avoids interference between the laser beam and the first winding portion. .

[0014] beforeThe second angle is preferably 5° or more and 45° or less.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a coiling machine and a method for manufacturing a coil spring that can improve the manufacturing efficiency of the coil spring and optimize the layout of various elements for manufacturing the coil spring.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a schematic perspective view showing a main part of a coiling machine according to an embodiment. [Figure 2] FIG. 2 is a schematic front view of a coiling machine according to an embodiment. [Figure 3] FIG. 3 is a flowchart showing the operation of a coiling machine according to an embodiment. [Figure 4] FIG. 4 is a schematic perspective view showing a specific example of a spiral forming process by a coiling machine according to an embodiment. [Figure 5] FIG. 5 is a schematic perspective view showing a specific example of a heating process by a coiling machine according to an embodiment. [Figure 6] FIG. 6 is a perspective view showing a first example of a method of heating and softening a part of a wire in a heating process. [Figure 7] FIG. 9 is a cross-sectional view of the wire along line IX-IX in FIG. 8. [Figure 8] FIG. 8 is a perspective view showing a second example of a method of heating and softening a part of a wire in a heating process. [Figure 9] FIG. 9 is a cross-sectional view of the wire along line IX-IX in FIG. 8. [Figure 10] FIG. 10 is a schematic perspective view showing a specific example of a cutting process by a coiling machine according to an embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of a wire irradiated with laser light. [Figure 12]Figure 12 is a cross-sectional view showing an example of a preferred positional relationship between the cutter, mandrel, and laser beam irradiation area. [Figure 13] Figure 13 is a cross-sectional view showing the state after the cutter has been lowered and the wire has been cut from the state shown in Figure 12. [Figure 14] Figure 14 is a schematic side view of a coil spring cut from a wire using the method shown in Figures 12 and 13. [Figure 15] Figure 15 is a schematic plan view of a coiling machine according to one embodiment, viewed parallel to the vertical direction. [Figure 16] Figure 16 is a schematic partial cross-sectional view of a coiling machine according to one embodiment, viewed parallel to the conveying direction. [Figure 17] Figure 17 is a schematic perspective view showing a coiling machine according to one modified example. [Modes for carrying out the invention]

[0017] The following describes embodiments of a coiling machine and a method for manufacturing coil springs with reference to the drawings.

[0018] Figure 1 is a schematic perspective view showing the main parts of the coiling machine 100 according to this embodiment. Figure 2 is a schematic front view of the coiling machine 100 shown in Figure 1. As shown in Figures 1 and 2, the conveying direction X, the vertical direction Y, the forming direction Z, and the circumferential direction Dθ are defined. The conveying direction X, the vertical direction Y, and the forming direction Z are orthogonal to each other. The conveying direction X is the direction in which the straight wire 1 is conveyed before being formed into a spiral. The forming direction Z is the direction in which the coil spring, formed by the spirally bent wire 1, extends (the direction in which the coil spring grows). The circumferential direction Dθ is the direction in which the wire 1 constituting the coil spring is wound.

[0019] The coiling machine 100 comprises a transport unit 10, a spiral forming unit 20, a heating unit (laser heater 30), a cutting unit 40, and a control unit 50.

[0020] In the examples shown in Figures 1 and 2, the transport unit 10 comprises a pair of drive rollers 11, a pair of driven rollers 12, and a wire guide 13. The transport unit 10 may have more drive rollers 11 and driven rollers 12.

[0021] Each drive roller 11 and each driven roller 12 are opposite each other via a wire 1. When each drive roller 11 rotates, each driven roller 12 rotates via the wire 1. As this rotation occurs, the wire 1, which is held between each drive roller 11 and each driven roller 12, is conveyed in the conveying direction X. The wire 1 is inserted into the wire guide 13. The wire guide 13 guides the wire 1 to move in a straight line in the conveying direction X, leading the wire 1 to the helical forming unit 20.

[0022] The spiral forming unit 20 forms the wire 1, which is conveyed by the conveying unit 10, into a spiral shape. In the examples shown in Figures 1 and 2, the spiral forming unit 20 includes a first forming roller 21, a second forming roller 22, and a pitch tool 23.

[0023] The first forming roller 21, the second forming roller 22, and the pitch tool 23 are arranged sequentially along the circumferential direction Dθ. The positions of the first forming roller 21, the second forming roller 22, and the pitch tool 23 in the forming direction Z are different from each other.

[0024] The first forming roller 21 and the second forming roller 22 sequentially bend the wire 1, which is being conveyed in the conveying direction X, in the vertical direction Y. The wire 1, bent in this manner, traces an arc along the circumferential direction Dθ. The bent wire 1 is guided by the pitch tool 23 at a position offset in the forming direction Z from the second forming roller 22.

[0025] As shown in Figure 2, the laser heating machine 30 irradiates a portion of the spirally shaped wire 1 with laser light L. This irradiation with laser light L creates a heated area 1V on the wire 1 that is hotter than other parts.

[0026] In the examples shown in Figures 1 and 2, the laser heater 30 comprises a laser oscillator 31, an optical fiber 32, and a laser head 33. The laser head 33 includes, for example, a beam spot adjuster.

[0027] For example, a semiconductor laser can be used as the laser oscillator 31 to generate laser light L. The optical fiber 32 transmits the laser light L generated by the laser oscillator 31 to the laser head 33. The laser head 33 adjusts the beam shape of the laser light L to a rectangular or circular shape using the beam spot adjuster described above. As the beam spot adjuster, for example, an optical element such as a beam homogenizer can be used.

[0028] The laser heater 30 may further include a measuring instrument 34 for measuring the temperature of the heated area 1V. The measuring instrument 34 has, for example, a sensor for detecting the temperature of the heated area 1V of the wire 1. The measuring instrument 34 may be located to the side of the cutting unit 40 to avoid interference with the cutting unit 40. The measuring instrument 34 may also be configured to move away from the cutter 41 in conjunction with the operation of the cutter 41 to avoid interference with the cutter 41, which will be described later. The measurement results from the measuring instrument 34 can be used, for example, to control the timing of the cutting of the wire 1 by the cutting unit 40.

[0029] Note that the measuring instrument 34 is not an essential component. In other words, various conditions for cutting the wire 1 can be set in advance without using the measuring instrument 34, and the cutting unit 40 may cut the heated portion 1V based on those conditions.

[0030] The laser heating machine 30 may further include a moving stage that moves the laser head 33 closer to and further away from the heating portion 1V of the wire 1. The moving stage can be configured, for example, as a linear stage or a robotic hand. If the working distance of the laser head 33 is set to be sufficiently long or interference with the cutting unit 40 can be avoided, it is not necessary to use a moving stage.

[0031] The cutting unit 40 cuts the heated portion 1V of the wire 1, which is hotter than before the laser beam was applied after the irradiation of the laser beam L has stopped. In the examples in Figures 1 and 2, the cutting unit 40 includes a cutter 41 and a mandrel 42.

[0032] The cutter 41 is positioned between the second forming roller 22 and the pitch tool 23 in the circumferential direction Dθ. The cutter 41 has, for example, a sharp cutting blade at its tip whose cutting edge is aligned with the forming direction Z. The cutter 41 is configured to be movable along the vertical direction Y by a drive mechanism (not shown).

[0033] The mandrel 42 is positioned inside the first forming roller 21, the second forming roller 22, and the pitch tool 23. The mandrel 42 has a semicircular shape along the XY plane, as shown in Figure 2, for example, and extends elongated in the forming direction Z. The mandrel 42 supports the inner circumferential surface of the spirally formed wire 1, mainly at its ends in the vertical direction Y of the arcuate surface.

[0034] The control unit 50 controls the transport unit 10, the helical forming unit 20, the laser heating machine 30, and the cutting unit 40. Such a control unit 50 includes a controller 51.

[0035] The controller 51 includes ROM (Read Only Memory), CPU (Central Processing Unit), and RAM (Random Access Memory). The ROM stores computer programs for controlling the transport unit 10, the spiral forming unit 20, the laser heating machine 30, and the cutting unit 40. The CPU executes the computer programs stored in the ROM. The RAM temporarily stores various data generated during the execution of the computer programs by the CPU.

[0036] Next, a method for manufacturing a coil spring 2 using the coiling machine 100 according to this embodiment will be described with reference to Figures 3 to 13.

[0037] Figure 3 is a flowchart showing the operation of the coiling machine 100. The operation shown in this flowchart is mainly achieved by the controller 51 executing a computer program. The manufacturing process of the coil spring 2 by the coiling machine 100 includes a helical forming process S01, a heating process S02, and a cutting process S03.

[0038] In the spiral forming process S01, the wire 1 is formed into a spiral shape. In the heating process S02, which follows the completion of the spiral forming process S01, a laser beam L is irradiated onto a portion of the wire 1, thereby forming a heated portion 1V on the wire 1. The heated portion 1V includes a portion that is softer than the rest of the wire 1 (base material). In the cutting process S03, which follows the completion of the heating process S02, the heated portion 1V of the wire 1 is cut.

[0039] Figure 4 is a schematic perspective view of a coiling machine 100 showing a specific example of the spiral forming process S01. In the spiral forming process S01, the conveying unit 10 guides the wire 1 in a straight line in the conveying direction X using the drive roller 11 and the driven roller 12 to the wire guide 13. The wire 1 led out from the wire guide 13 is bent in the vertical direction Y by the first forming roller 21 and the second forming roller 22 and formed into an arc shape. The arc-shaped wire 1 is guided by the pitch tool 23 to be formed into a spiral shape with a predetermined pitch. Through this operation, the spiral wire 1 gradually extends in the forming direction Z.

[0040] Figure 5 is a schematic perspective view of the coiling machine 100 showing a specific example of the heating process S02. In the heating process S02, the laser heater 30 directly irradiates the portion of the spirally formed wire 1 located near the end in the vertical direction Y of the mandrel 42 (below the cutter 41) with laser light L. The energy of this laser light L heats the base material of the wire 1 and forms a softened heated portion 1V.

[0041] During the heating process S02, the transport of the wire 1 by the transport unit 10 is stopped. The laser heater 30 is fixedly positioned, for example, at a predetermined location, and irradiates a portion of the stopped wire 1 with laser light L from this position. As another example, if the laser heater 30 has the moving stage described above, the laser heater 30 may bring the laser head 33 closer to the wire 1 before irradiating the laser light L. Alternatively, the laser heater 30 may irradiate the portion of the wire 1 being transported in the circumferential direction Dθ without stopping the transport of the wire 1 by the transport unit 10 during the heating process S02. In this case, the movement of the laser heater 30 may be controlled so that the irradiation position of the laser light L moves in accordance with the movement of the cutting position due to coiling.

[0042] Figure 6 is a perspective view of wire 1 showing a first example of a method for heating and softening a portion of the wire 1. In this example, the laser heater 30 irradiates the surface of wire 1 with laser light L1 in the irradiation direction DL. The laser light L1 has, for example, a beam profile that is elongated in the width direction of wire 1. A heated area 1V is formed in the irradiation area 1a of wire 1 and its surroundings when irradiated with this laser light L1.

[0043] Figure 7 is a cross-sectional view of wire 1 along the line VII-VII in Figure 6. The heated area 1V extends not only around the irradiation area 1a on the surface of wire 1, but also into the interior of wire 1. In this example, the width WD1 of the laser beam L1 in the width direction of wire 1 is smaller than the diameter R of wire 1. Therefore, most of the laser beam L1 is irradiated onto wire 1.

[0044] Figure 8 is a perspective view of wire 1 showing a second example of a method for heating and softening a portion of wire 1. In this example, the laser heater 30 irradiates the surface of wire 1 with laser light L2 in the irradiation direction DL. The laser light L2 has, for example, a circular beam profile. Similar to the first example, a heated area 1V is formed in and around the irradiation area 1a of wire 1 irradiated with this laser light L2.

[0045] Figure 9 is a cross-sectional view of wire 1 along the line IX-IX in Figure 8. The heated area 1V extends not only around the irradiation area 1a on the surface of wire 1, but also into the interior of wire 1. For example, the width WD2 (diameter) of the laser beam L2 is smaller than the diameter R of wire 1. Therefore, most of the laser beam L2 is irradiated onto wire 1.

[0046] The heated area 1V may extend further into the wire 1 than in the examples shown in Figures 7 and 9. The shape of the laser beam L emitted by the laser heater 30 is not limited to the first and second examples.

[0047] In both the first and second examples, the heated area 1V may include a molten pool formed by the melting of the base material of the wire 1 by the energy of the laser beam L. The molten pool may extend not only to the irradiated area 1a but also to its surroundings.

[0048] Figure 10 is a schematic perspective view of the coiling machine 100 showing a specific example of the cutting process S03. In this embodiment, the cutting process S03 is performed after the irradiation of the laser beam L is stopped. In another example, the cutting process S03 may be performed while the laser beam L is being irradiated. In the cutting process S03, the heated portion 1V of the wire 1, which is hotter than before the laser beam L was irradiated, is cut by the cutting unit 40. This produces a coil spring 2.

[0049] Specifically, in the cutting process S03, the cutter 41 descends toward the vicinity of the portion of the wire 1 supported by the mandrel 42. At this time, the wire 1 is cut by the impact applied by the cutter 41.

[0050] If the heating area 1V includes a molten pool, the molten pool may solidify between the time the laser beam L stops irradiating and the time the cutter 41 starts operating. Alternatively, after the cutter 41 has started operating, the heat from the heating area 1V may be removed by the cutter 41 when it comes into contact with the surface of the wire 1, causing the molten pool to solidify. In this way, solidification of the molten pool before or during the operation of the cutter 41 can prevent the molten metal from adhering to the cutter 41.

[0051] In the cutting process S03, the cutter 41 can also be operated based on the temperature measurement result of the measuring instrument 34 for the heated area 1V. That is, after irradiation with the laser beam L, the cutter 41 may be operated when the temperature of the heated area 1V drops to a predetermined target temperature. The above target temperature may be, for example, the temperature at which the molten base material solidifies. Of course, in the cutting process S03, the heated area 1V may be cut without using the measuring instrument 34 by pre-determining a delay time from the stop of irradiation with the laser beam L to the start of operation of the cutter 41.

[0052] The cut coil spring 2 has a first end 61 including a first end face 61a and a second end 62 including a second end face 62a. After one coil spring 2 is manufactured, the helical forming process S01, heating process S02, and cutting process S03 described above are performed again to manufacture the next coil spring 2. Therefore, both the first end 61 and the second end 62 are cut through the above-described processes.

[0053] The shear force required to cut wire 1 decreases as the wire 1 is heated and its temperature rises. Furthermore, the shear force can be reduced even if wire 1 has not reached its melting point. Moreover, this tendency does not depend on the diameter of wire 1. As an example, when cutting wire 1 with cutter 41, it is preferable that the temperature of at least a portion of the heated area 1V is 500°C or higher.

[0054] Figure 11 is a schematic cross-sectional view of wire 1 irradiated with laser light L. Here, we assume that laser light L2, having the shape shown in Figure 8, is irradiated onto the surface of wire 1, forming a molten pool. In the figure, O indicates the center of the irradiation region 1a (see Figures 6 and 8) of laser light L on the outer surface of wire 1. For example, this irradiation center O corresponds to the position where the highest intensity peak portion of the laser light L beam profile is irradiated. Alternatively, the irradiation center O can be considered as the center of the molten pool.

[0055] As described above, when the laser beam L is irradiated onto the wire 1, a heated area 1V is formed. During or immediately after irradiation with the laser beam L, a molten pool is formed around the irradiation center O. Subsequent cooling causes the molten pool to solidify, forming a hardened area 1C. Around the molten pool, a heat-affected zone 1H (HAZ) is formed, which is not melted but has altered properties from the base material of the wire 1 due to the heat generated during irradiation with the laser beam L. Thus, the heated area 1V includes the hardened area 1C and the heat-affected zone 1H.

[0056] Figure 11 shows the results of measuring the Vickers hardness [HV] for the quenched hardened portion 1C, the heat-affected zone 1H, and the base material of wire 1. The quenched hardened portion 1C is generally harder than the base material. On the other hand, the heat-affected zone 1H is generally harder than the base material. The hardness of the heat-affected zone 1H gradually increases from the vicinity of the quenched hardened portion 1C towards the base material.

[0057] Thus, the hardness distribution is not uniform even in the heated area 1V. Therefore, it is necessary to appropriately determine the relationship between the positions of the cutter 41 and the mandrel 42 and the irradiation area of ​​the laser beam L.

[0058] Figure 12 is a cross-sectional view showing an example of a preferred positional relationship between the cutter 41, the mandrel 42, and the irradiation area of ​​the laser beam L. In the helical forming process S01 described above, the helically formed wire 1 is fed between the cutter 41 and the mandrel 42. In the feeding direction of the wire 1 (circumferential direction Dθ), a clearance G is provided between the end 41a of the cutter 41 and the end 42a of the mandrel 42. Hereinafter, the center of the clearance G in the circumferential direction Dθ will be referred to as the clearance center C.

[0059] In the example shown in Figure 12, the clearance center C and the irradiation center O are offset in the circumferential direction Dθ. Specifically, the irradiation center O is located on the cutter 41 side (downstream in the circumferential direction Dθ) of the clearance center C.

[0060] In the example shown in Figure 12, the heated area 1V includes a molten pool 1P that will become the hardened portion 1C described above after solidification. For example, the molten pool 1P overlaps with the clearance center C. Also, the molten pool 1P overlaps with the end portion 41a of the cutter 41 in the vertical direction Y.

[0061] On the other hand, the molten pool 1P does not overlap with the end portion 42a of the mandrel 42 in the vertical direction Y. In the example in Figure 12, the end portion 42a of the mandrel 42 and the portion of the heat-affected zone 1H located upstream of the molten pool 1P in the circumferential direction Dθ overlap in the vertical direction Y.

[0062] Figure 13 is a cross-sectional view showing the state in which the wire 1 is cut by lowering the cutter 41 parallel to the vertical direction Y from the state shown in Figure 12. As described above, when the wire 1 is cut by the cutter 41, the molten pool 1P is either already solidified or solidifies due to heat being removed by contact with the cutter 41. Therefore, a hardened portion 1C is formed during cutting. Note that some of the molten pool 1P may remain inside the heated portion 1V during cutting.

[0063] When the tip of the cutter 41 strikes the outer surface of the wire 1 protruding from the end 42a of the mandrel 42, a shear force is applied to the heated area 1V and its surroundings, causing the wire 1 to break. The cutter 41 descends, for example, up to near the axis of the wire 1. An indentation B (recess) is formed in the cut wire 1, i.e., the coil spring 2, by the cutter 41. In the example in Figure 13, the hardened portion 1C and the heat-affected portion 1H overlap with the indentation B, but they may be offset from each other.

[0064] As described above, the heat-affected zone 1H is softer than the hardened zone 1C and the base material of the wire 1. Therefore, when the cutter 41 impacts the wire 1, the heat-affected zone 1H is prone to fracture at the heated area 1V. In particular, as shown in Figure 12, if the irradiation center O is shifted towards the cutter 41 side of the clearance center C, a load can be effectively applied to the portion of the heat-affected zone 1H located upstream of the molten pool 1P in the circumferential direction Dθ, causing the wire 1 to fracture along that portion.

[0065] Figure 14 is a schematic side view of a coil spring 2 cut from wire 1 in the manner shown in Figures 12 and 13. The coil spring 2 has a first end 61 including a first end face 61a and a second end 62 including a second end face 62a.

[0066] The first end face 61a corresponds to the fracture surface of the coil spring 2 separated from the wire 1 in Figure 13. The first end face 61 has a first irradiation mark M1 of the laser beam L and an indentation B of the cutter 41. The first irradiation mark M1 includes a hardened portion 1C and a heat-affected zone 1H (first heat-affected zone).

[0067] The second end face 62a corresponds to the fracture surface of the wire 1 that remained above the mandrel 42 when a coil spring 2 manufactured before this coil spring 2 was cut. The second end face 62 has a second irradiation mark M2 of the laser beam L. The second irradiation mark M2 includes a heat-affected zone 1H (second heat-affected zone). If the wire 1 is cut as shown in Figure 13, the second irradiation mark M2 does not include a hardened portion 1C. However, the second irradiation mark M2 may include a smaller amount of hardened portion 1C than, for example, the first irradiation mark M1.

[0068] The heat-affected zone 1H contained in the first irradiation mark M1 extends to at least a portion of the first end face 61a. Similarly, the heat-affected zone 1H contained in the second irradiation mark M2 extends to at least a portion of the second end face 62a. On the other hand, the quenched hardened portion 1C contained in the first irradiation mark M1 does not extend to the first end face 61a. However, a portion of the quenched hardened portion 1C may extend to the first end face 61a. In this case, it is preferable that the area of ​​the quenched hardened portion 1C on the first end face 61a is smaller than the area of ​​the heat-affected zone 1H.

[0069] Next, we will explain the irradiation direction DL of the laser beam L. Figure 15 is a schematic plan view of the coiling machine 100 as seen parallel to the vertical direction Y. In this figure, the wire 1, drive roller 11, wire guide 13, second forming roller 22, pitch tool 23, and mandrel 42 shown in Figure 1 and other figures are shown, and the main body 110 and cover 120 of the coiling machine 100 are shown with dashed lines.

[0070] The main body 110 houses a drive source and control unit 50, which share power with the conveying unit 10, the spiral forming unit 20, and the cutting unit 40. The main body 110 supports the drive roller 11, wire guide 13, second forming roller 22, pitch tool 23, and mandrel 42, and is located on the opposite side of the forming direction Z from these components. The cover 120 is located on the Z side of the forming direction relative to the drive roller 11, wire guide 13, second forming roller 22, pitch tool 23, and mandrel 42. In the example in Figure 15, the cover 120 is not provided near the spirally bent wire 1. Note that the coiling machine 100 does not necessarily have to have the cover 120.

[0071] In the plan view of Figure 15, the shaping direction Z is defined as 0°, the opposite side of the transport direction X as 90°, the opposite side of the shaping direction Z as 180°, and the transport direction X as 270°, with respect to the irradiation area 1a of the laser beam L on the surface of the wire 1. Furthermore, the angle between the irradiation direction DL of the laser beam L and the shaping direction Z is defined as the first angle θ1. In addition, the portion of the spirally shaped wire 1 (coil spring 2) located above the mandrel 42 is called the 0th turn P0, and the portion adjacent to the 0th turn P0 in the shaping direction Z is called the 1st turn P1.

[0072] The first angle θ1 must be determined so that the laser head 33 and the laser beam L do not interfere with the spirally shaped coil spring 2. In the example in Figure 15, interference between the laser beam L and the first coil P1 is likely when the laser beam L is irradiated onto the irradiation area 1a from the range of 270° to 360° (0°). Therefore, in this embodiment, the first angle θ1 is determined within the range R1a of 0° or more and 270° or less.

[0073] The second molding roller 22 is positioned in the range of 180° to 270°. Since the second molding roller 22 is located close to the irradiation area 1a, the laser head 33 and laser beam L are likely to interfere with the second molding roller 22 when the first angle θ1 is in this range. Therefore, it is more preferable to set the first angle θ1 within the range R1b, which is between 0° and 180°. When the first angle θ1 is within the range R1b, the laser head 33 is located upstream of the irradiation area 1a in the transport direction X.

[0074] Furthermore, as shown in Figure 12, setting the irradiation center O of the laser beam L downstream of the end 42a of the mandrel 42 in the circumferential direction Dθ (opposite side of the transport direction X), and defining the first angle θ1 within the range R1b is more advantageous because it reduces interference between the laser head 33 and the laser beam L and the cutter 41.

[0075] The main body 110 is positioned in the range of 90° to 180°. The pitch tool 23 is positioned near 90°. If a cover 120 is provided, interference with this cover 120 must also be avoided. Therefore, it is even more preferable to set the first angle θ1 within the range of 0° or more and 80° or less.

[0076] Figure 16 is a schematic partial cross-sectional view of the coiling machine 100, viewed parallel to the conveying direction X. In this figure, only the portion of the spirally bent wire 1 (coil spring 2) and mandrel 42 located above the central axis AX of the coil spring 2 is shown.

[0077] In the cross-sectional view of Figure 16, the vertical direction Y is defined as 0° and the molding direction Z as 90°, with respect to the irradiation area 1a of the laser beam L. Furthermore, the angle between the irradiation direction DL of the laser beam L and the vertical direction Y is defined as the second angle θ2.

[0078] Similar to the first angle θ1, the second angle θ2 must be determined so that the laser head 33 and laser beam L do not interfere with the various parts of the coiling machine 100 or the first winding P1. To avoid interference with the main body 110 and the wire 1 after the first winding P1, the second angle θ2 is set within a range of at least 0° and 90°.

[0079] The first turn P0 is in contact with the first forming roller 21, the second forming roller 22, the pitch tool 23, and the mandrel 42. On the other hand, the first turn P1 is free from these contacts, so the outer diameter of the first turn P1 and subsequent turns may be larger than the outer diameter of the first turn P0, as shown in Figure 16.

[0080] Since the cutter 41 is located directly above the irradiation area 1a, it is difficult to set the second angle θ2 to 0°. Furthermore, in order to avoid interference with the first winding P1, which has a larger outer diameter than the first winding P0, the second angle θ2 must be less than 90°. Therefore, it is preferable to set the second angle θ2 within the range R2a of 5° or more and 80° or less.

[0081] As shown in the example in Figure 16, when the irradiation area 1a is located near the outermost edge of the wire 1 on the mandrel 42, a large second angle θ2 can cause the irradiation area 1a to expand, potentially reducing the heating efficiency of the wire 1. Therefore, it is preferable to keep the second angle θ2 as small as possible within the range R2a. In one example, good heating efficiency can be obtained by setting the second angle θ2 within the range R2b of 5° or more and 45° or less.

[0082] Note that the conditions that the first angle θ1 belongs to one of the ranges R1a, R1b, or R1c, and the conditions that the second angle θ2 belongs to one of the ranges R2a or R2b, do not necessarily have to be met simultaneously.

[0083] According to this embodiment, the portion of the spirally bent wire 1 that has become hot due to irradiation with laser light L (heated portion 1V) is cut by the cutting unit 40 (cutter 41 and mandrel 42), thus reducing the shear force required for cutting. Therefore, the wire 1 can be easily cut.

[0084] Furthermore, as explained using Figures 15 and 16, by defining the irradiation direction DL of the laser beam L, it becomes possible to efficiently arrange the laser head 33 and various elements, suppress interference between the laser beam L and the various elements, and improve the heating efficiency of the wire 1.

[0085] The above embodiments do not limit the scope of the present invention to the configurations disclosed in those embodiments. The present invention can be implemented by modifying the configurations disclosed in those embodiments in various ways.

[0086] For example, when implementing the present invention, it goes without saying that the configuration and arrangement of each element of the coiling machine 100 can be changed in various ways as needed.

[0087] In each embodiment, an example was shown in which the coiling machine 100 cuts the heated portion 1V of the wire 1 using a cutter 41. The coiling machine 100 is not limited to this configuration, and the heated portion 1V of the wire 1 may also be cut by cutting with a rotary saw blade.

[0088] The coil spring 2 produced by the coiling machine 100 can take on various forms; for example, the coil diameter and pitch may vary in the axial direction of the coil spring. That is, the coil spring 2 produced by the coiling machine 100 can be of various forms, including cylindrical coil springs, barrel-shaped coil springs, drum-shaped coil springs, tapered coil springs, unequal pitch coil springs, coil springs with negative pitch sections, and so on. The first angle θ1 and the second angle θ2 described above can be set to appropriate values ​​depending on the shape of the coil spring, so that the laser beam L does not interfere with the first turn P1 and subsequent turns.

[0089] In each figure, an example of a coiling machine 100 and manufacturing method for producing a right-handed coil spring wound clockwise from the end is shown. The configuration disclosed in this embodiment can also be applied to a coiling machine and manufacturing method for producing a left-handed coil spring wound counterclockwise from the end.

[0090] Figure 17 is a schematic perspective view showing an example of a coiling machine 200 for manufacturing left-handed coil springs. The coiling machine 200 has similar elements to the coiling machine 100, except that in the example in Figure 17, the elements are arranged in an inverted positional relationship to those shown in Figures 1, 2, 4, 5, and 10.

[0091] In the coiling machine 200 shown in Figure 17, the definitions of the conveying direction X, the vertical direction Y, and the molding direction Z are the same as in the examples in Figures 1, 2, 4, 5, and 10. Therefore, the conditions for the first angle θ1 and the second angle θ2 explained using Figures 15 and 16 can also be applied to the coiling machine 200. [Explanation of symbols]

[0092] 1…Wire, 1V…Heating area, 1P…Melting pool, 1C…Heat-affected zone, 1H…Heat-affected zone, 2…Coil spring, 10…Conveying unit, 11…Driven roller, 12…Driven roller, 13…Wire guide, 20…Spiral forming unit, 21…First forming roller, 22…Second forming roller, 23…Pitch tool, 30…Laser heater, 31…Laser oscillator, 32…Optical fiber, 33…Laser head, 34…Measuring instrument, 40…Cutting unit, 41...Cutter, 42...Mandrel, 50...Control unit, 51...Controller, 61...First terminal, 62...Second terminal, 100,200...Coiling machine, L,L1,L2...Laser light, S01...Spiral forming process, S02...Heating process, S03...Cutting process, M1...First irradiation mark, M2...Second irradiation mark, B...Indentation, X...Conveying direction, Y...Vertical direction, Z...Forming direction, Dθ...Circumferential direction, DL...Irradiation direction, θ1...First angle, θ2...Second angle.

Claims

1. A conveying unit that conveys wires in the conveying direction, A spiral forming unit that forms a coil spring extending spirally in the direction of the conveying direction and the forming direction perpendicular to the vertical direction by sequentially bending the wire conveyed by the conveying unit in a vertical direction perpendicular to the conveying direction, A laser heating machine that heats a portion of the wire by irradiating the wire, which has been bent by the helical forming unit, A cutting unit for cutting the portion of the wire heated by the laser light, A main body located on the opposite side of the molding direction from the conveying unit, the helical forming unit, and the cutting unit, and which supplies power to the conveying unit, the helical forming unit, and the cutting unit, Equipped with, The helical forming unit comprises a forming roller that sequentially bends the wire, which is conveyed in the conveying direction by the conveying unit, in the vertical direction, and a pitch tool that guides the bent wire at a position offset from the forming roller in the forming direction. The cutting unit comprises a mandrel that supports the inner circumferential surface of the wire bent by the forming roller, and a cutter that cuts the wire by applying an impact to the outer circumferential surface of the wire protruding from the end of the mandrel. The irradiation center of the laser beam on the outer surface of the wire is located at a position offset from the end of the mandrel to the opposite side of the transport direction. With respect to the irradiation area of ​​the laser beam on the wire, if the molding direction is defined as 0°, the opposite side of the transport direction as 90°, the opposite side of the molding direction as 180°, and the transport direction as 270°, the molding roller is positioned in the range of 180° to 270°, the pitch tool is positioned around 90°, and the irradiation direction of the laser beam from the laser heater forms a first angle with respect to the molding direction that is 0° or more and 80° or less, thereby avoiding interference between the laser beam and the main body, the molding roller, the pitch tool, and the cutter. Coiling machine.

2. The main body, the transport unit, the molding roller, and the pitch tool are further comprising a cover located on the molding direction side, The laser beam is configured to avoid interference between the laser beam and the cover by having the irradiation direction of the laser beam form a first angle with respect to the molding direction that is 0° or more and 80° or less. The coiling machine according to claim 1.

3. The wire formed in a spiral shape by the spiral forming unit includes a zero-turn portion that contacts the forming roller, the pitch tool and the mandrel, and a first-turn portion that is adjacent to the zero-turn portion in the forming direction and does not contact the forming roller, the pitch tool and the mandrel, The outer diameter of the first turn is larger than the outer diameter of the zero turn. The laser heating machine irradiates the zero-turn portion with the laser light, With respect to the irradiation area, and with the vertical direction set to 0° and the molding direction set to 90°, the irradiation direction forms a second angle with respect to the vertical direction of 5° or more and 80° or less, thereby preventing interference between the laser beam and the first coil portion. The coiling machine according to claim 1.

4. The second angle is 5° or more and 45° or less. The coiling machine according to claim 3.

5. A method for manufacturing a coil spring using a coiling machine according to any one of Claims 1 to 4.

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