Helical wire manufacturing apparatus, piston ring manufacturing apparatus, helical wire manufacturing method, piston ring manufacturing method

Abstract

To suppress the wound diameter variation when manufacturing a spiral coil.SOLUTION: In a spiral wire rod manufacturing apparatus 1, a spiral coil 90 obtained by bending a wire rod 2 supplied from a wire rod supply device 10 by a bending processing device 20 is supported by a support core part 70. The bending processing device 20 comprises from the upstream side to the downstream side: a first molding roller 30 which comes into contact with a wire rod outer peripheral surface 2A; a second molding roller 40 which comes into contact with a wire rod inner peripheral surface 2B; a third molding roller 50 which comes into contact with the wire rod outer peripheral surface 2A; a drawing guide 60 which comes into contact with the wire rod inner peripheral surface 2B and draws the wire rod 2 to the outer side in the radial direction; and a push-in guide 65 which comes into contact with the wire rod outer peripheral surface 2A.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a spiral wire manufacturing apparatus that curves a linear wire into a spiral shape.

Background Art

[0002] Conventionally, when manufacturing piston rings, compression coil springs, torsion coil springs, etc., a spiral wire manufacturing apparatus is used. This spiral wire manufacturing apparatus guides a linear and metallic wire by a wire supply apparatus to a bending apparatus, and in this bending apparatus, the wire is bent (plastic processed) into an arc shape. The wire continuously bent in the bending apparatus becomes a spiral coil. In the case of a piston ring, this spiral coil may be cut afterwards in units of one turn (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although it is the finding of the present inventors that is unknown at the time of the present application, for example, in a spiral wire manufacturing apparatus, when manufacturing such that the central axis of the spiral coil becomes horizontal, as the number of turns of the spiral coil output from the bending apparatus increases, the self-weight of the spiral coil can adversely affect the bending apparatus. Therefore, when passing a core member through the output spiral coil and attempting to receive the self-weight of the spiral coil by this core member, in turn, a sliding resistance occurs between the core member and the spiral coil, which can adversely affect the bending apparatus. There was a problem that the adverse effects of self-weight and sliding resistance appeared as fluctuations in the coil diameter of the spiral coil.

[0005] In view of these circumstances, the present invention aims to provide a spiral wire manufacturing apparatus and the like that can suppress winding diameter fluctuations. [Means for solving the problem]

[0006] The present invention, which achieves the above objective, comprises a wire supply device that supplies a straight, metallic wire, a bending device disposed downstream of the wire supply device for bending the wire into an arc shape, and a support core that supports the inner surface of the wire which becomes a helical coil after passing through the bending device, wherein the outer surface of the helical coil on the wire is defined as the outer surface of the wire, and the inner surface of the helical coil is defined as the inner surface of the wire, and the wire center path is defined as a virtual line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position), the bending device has a first forming rod that contacts the outer surface of the wire supplied from the wire supply device A spiral wire manufacturing apparatus comprising: a first forming roller; a second forming roller that contacts the inner surface of the wire downstream of the wire center path from the contact area between the first forming roller and the outer surface of the wire (hereinafter referred to as the first contact area); a third forming roller that contacts the outer surface of the wire downstream of the wire center path from the contact area between the second forming roller and the inner surface of the wire (hereinafter referred to as the second contact area); a pull guide that contacts the inner surface of the wire downstream of the wire center path from the contact area between the third forming roller and the outer surface of the wire (hereinafter referred to as the third contact area); and a push guide that contacts the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area).

[0007] In relation to the above-described spiral wire manufacturing apparatus, when defining the direction in which the wire bends to form a spiral coil as the forward bending direction and the direction in which the wire bends in the opposite direction to the forward bending direction as the reverse bending direction, the first contact region and the third contact region press the wire against the second contact region, thereby displacing the wire in the reverse bending direction in the first contact region and displacing the wire in the forward bending direction in the second contact region.

[0008] In relation to the above-described spiral wire manufacturing apparatus, the wire may be characterized in that it is displaced within the range of elastic deformation in the pull guide contact region.

[0009] In relation to the above-described spiral wire manufacturing apparatus, the contact area between the push guide and the inner circumferential surface of the wire (hereinafter referred to as the push guide contact area) may be characterized in that the wire is displaced within the range of elastic deformation.

[0010] In relation to the spiral wire manufacturing apparatus described above, a virtual line along the outer surface of the wire in the wire passage path from the wire supply position in the wire supply device to the core contact position is defined as the outer wire path, and assuming that the pushing guide does not contact the outer surface of the wire, the outer wire path defined in the first winding of the wire is defined as the initial non-pushing outer wire path, and the contact area between the pushing guide and the inner surface of the wire (hereinafter referred to as the pushing guide contact area) is set at the same position as the initial non-pushing outer wire path, or radially inward in terms of the radius of curvature than the initial non-pushing outer wire path.

[0011] In relation to the spiral wire manufacturing apparatus described above, the push guide contact area may be characterized in that it is set at a location at a distance of 0.1% or more of the radius of curvature, radially inward from the initial wire outer path when not being pushed in.

[0012] In relation to the spiral wire manufacturing apparatus described above, the distance along the wire center path from the center point on the wire center path in the pull guide contact area (hereinafter referred to as the pull guide center point) to the center point on the wire center path in the contact area between the push guide and the inner circumferential surface of the wire (hereinafter referred to as the push guide contact area) (hereinafter referred to as the push guide center point) may be set to 2.7% or more of the circumference of one rotation of the center line of the wire in the spiral coil.

[0013] In relation to the spiral wire manufacturing apparatus described above, the distance along the wire center path from the center point on the wire center path in the pull guide contact area (hereinafter referred to as the pull guide center point) to the center point on the wire center path in the contact area between the push guide and the inner circumferential surface of the wire (hereinafter referred to as the push guide contact area) (hereinafter referred to as the push guide center point) may be set to 33.3% or less of the circumference of one rotation of the center line of the wire in the spiral coil.

[0014] In relation to the above-described spiral wire manufacturing apparatus, it may be characterized by being equipped with a path detection device that detects the displacement of the wire passage path downstream of the bending device.

[0015] In relation to the above-described spiral wire manufacturing apparatus, the spiral coil may be characterized by being a material for piston rings.

[0016] To achieve the above objective, the present invention comprises the above-mentioned helical wire manufacturing apparatus and a dividing apparatus for cutting the helical coil and dividing it into single-winding piston ring members,

[0017] This is a piston ring manufacturing apparatus characterized by being equipped with [a specific feature].

[0018] To achieve the above objective, the present invention provides a wire supply device that supplies a straight, metallic wire, a bending device located downstream of the wire supply device that bends the wire into an arc shape, and a support core that supports the inner surface of the wire, which becomes a spiral coil after passing through the bending device. The outer surface of the spiral coil on the wire is defined as the outer surface of the wire, and the inner surface of the spiral coil is defined as the inner surface of the wire. The wire center path is defined as a virtual line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position). In the bending device, the first forming roller is brought into contact with the outer surface of the wire supplied from the wire supply device. The method for manufacturing a spiral wire is characterized by the following: bringing the second molding roller into contact with the inner surface of the wire downstream of the wire center path from the contact area between the first molding roller and the outer surface of the wire (hereinafter referred to as the first contact area); bringing the third molding roller into contact with the outer surface of the wire downstream of the wire center path from the contact area between the second molding roller and the inner surface of the wire (hereinafter referred to as the second contact area); bringing the pull guide into contact with the inner surface of the wire downstream of the wire center path from the contact area between the third molding roller and the outer surface of the wire (hereinafter referred to as the third contact area); and bringing the push guide into contact with the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area).

[0019] To achieve the above objective, the present invention is a piston ring manufacturing method characterized by cutting the helical coil manufactured by the above-described helical wire manufacturing method into single-winding sections to form a piston ring member. [Effects of the Invention]

[0020] According to the present invention, it is possible to achieve the excellent effect of being able to manufacture spiral wires with a stable winding diameter. [Brief explanation of the drawing]

[0021] [Figure 1] (A) is a front view showing the overall configuration of the spiral wire manufacturing apparatus according to an embodiment of the present invention during the first winding, and (B) is a plan view showing the overall configuration of the spiral wire manufacturing apparatus during the first winding. [Figure 2] (A) is a front view showing the overall configuration of the spiral wire manufacturing apparatus during multiple windings, and (B) is a plan view showing the overall configuration of the spiral wire manufacturing apparatus during multiple windings. [Figure 3] (A) is a block diagram showing the internal configuration of the control device of the spiral wire manufacturing apparatus, and (B) is a block diagram showing the functional configuration of the program of the control device. [Figure 4] (A) is a front view showing the overall configuration of the spiral wire manufacturing apparatus in the non-pushed state during the first winding, and (B) is a front view showing the overall configuration of the spiral wire manufacturing apparatus in the non-pushed state during multiple windings. [Figure 5] (A) is a graph showing the measurement result of the detection signal of the lead-out path detection device in the process of manufacturing a spiral coil by the spiral wire manufacturing apparatus in the non-pushed state, and (B) is a graph showing the amount of change in the diameter of the spiral coil manufactured by the spiral wire manufacturing apparatus in the non-pushed state. [Figure 6] (A) is a front view showing the overall configuration of the spiral wire manufacturing apparatus in the non-pushed state during the first winding, and (B) is a front view showing the overall configuration of the spiral wire manufacturing apparatus in the pushed state during the first winding. [Figure 7] It is a front view showing the overall configuration of the spiral wire manufacturing apparatus in the pushed state during multiple windings. [Figure 8] (A) is a graph showing the measurement result of the detection signal of the lead-out path detection device in the process of manufacturing a spiral coil by the spiral wire manufacturing apparatus in the pushed state, and (B) is a graph showing the amount of change in the diameter of the spiral coil manufactured by the spiral wire manufacturing apparatus in the pushed state. [Figure 9](A) is a graph showing the measurement results of the detection signal of the output path detection device during the process of manufacturing a spiral coil using a spiral wire manufacturing device in a pressed state, and (B) is a graph showing the change in diameter of the spiral coil manufactured by the spiral wire manufacturing device in a pressed state. [Figure 10] (A) is a graph showing the measurement results of the detection signal of the output path detection device during the process of manufacturing a spiral coil using a spiral wire manufacturing device in a pressed state, and (B) is a graph showing the change in diameter of the spiral coil manufactured by the spiral wire manufacturing device in a pressed state. [Figure 11] (A) is a graph showing the measurement results of the detection signal of the output path detection device during the process of manufacturing a spiral coil using a spiral wire manufacturing device in a pressed state, and (B) is a graph showing the change in diameter of the spiral coil manufactured by the spiral wire manufacturing device in a pressed state. [Figure 12] (A) is a graph showing the measurement results of the detection signal of the output path detection device during the process of manufacturing a spiral coil using a spiral wire manufacturing device in a pressed state, and (B) is a graph showing the change in diameter of the spiral coil manufactured by the spiral wire manufacturing device in a pressed state. [Figure 13] (A) is a plan view showing how a helical coil is divided together by a dividing device, and (B) is a front view showing the divided piston rings. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] Figure 1 shows the overall configuration of a spiral wire manufacturing apparatus 1 according to an embodiment of the present invention. The spiral wire manufacturing apparatus 1 is a device that continuously bends a straight, metallic wire 2 of a predetermined length to form a spiral wire (hereinafter referred to as a spiral coil 90). The spiral wire manufacturing apparatus 1 includes a wire supply device 10, a bending device 20, a cutting device 300, a support core 70, an output path detection device 80, and a control device 85. In this embodiment, the spiral coil 90 is used as a material when manufacturing piston rings. In other words, this spiral wire manufacturing apparatus 1 becomes part of a piston ring manufacturing apparatus.

[0024] (Various definitions) When describing the spiral wire manufacturing apparatus 1, the following definitions will be used as appropriate. Outer surface 2A of the wire: In the wire 2 into which the helical coil 90 is formed, this surface is located on the outer surface of the helical coil 90. Inner circumferential surface 2B of the wire: In the wire 2 from which the helical coil 90 is formed, this surface is located on the inner circumferential side of the helical coil 90. Virtual spiral axis G: The virtual central axis in the spiral coil 90 (orthogonal to the plane of the paper in Figure 1(A)). Wire passage path T: The path taken by the wire 2 from the wire supply device 10 to the bending device 20 until it reaches the support core 70. Wire center path P: A virtual line along the center line of wire 2 passing through wire passage path T. Wire outer path PA: A virtual line along the outer surface 2A of wire 2 that passes through wire passage path T. Wire inner path PB: A virtual line along the inner circumference 2B of wire 2 that passes through wire passage path T. Linear guidance direction X: The direction in which the wire 2 is guided linearly from the wire supply device 10 to the bending device 20 (may be set to horizontal). Linear guidance orthogonal axis Z: A virtual axis perpendicular to both the linear guidance direction X and the virtual spiral axis G (may be set to vertical). The positive direction ZB of the orthogonal axis Z of the linear guidance: the direction in which the wire 2 guided in the linear guidance direction X is wound (downward in Figure 1(A)). The opposite direction ZA of the orthogonal axis Z of the linear guide: the opposite direction to the positive direction ZB (upward in Figure 1(A)). Linear guidance region T1: The path in the wire passage path T from the wire supply device 10 to the first part of the bending device 20 where the wire 2 reaches. Bending region T2: Starting from the point where the wire 2 reaches the first bending-related component (a component that affects the bending process) of the bending device 20 in the wire passage path T (the end point of the linear guide region T1), the path extends from the last bending-related component of the bending device 20 to the point where the wire 2 is released. Post-processing exit region T3: Starting from the point where the wire 2 is released from the last bending-related component of the bending device 20 in the wire passage path T (the end point of the bending region T2), this is the path the wire 2 takes until it reaches the support core 70 (see Figure 2(A)). Coil average diameter Kr: The diameter obtained by averaging the arc diameter (unit coil diameter) of each winding formed by the centerline of the wire 2 of the helical coil 90 being formed over all windings (see Figure 2(B)). Coil average circumference: The average circumference (average coil diameter × pi) obtained by averaging the arc length (unit coil circumference) of each turn formed by the centerline of wire 2 in the spiral coil 90 over all turns.

[0025] (Wire supply device) The wire supply device 10 guides a straight, metallic wire 2 linearly to the bending device 20. In this embodiment, the linear guidance direction X of the wire 2 by the wire supply device 10 is set to the horizontal direction, with the outer circumferential surface 2A being vertically upward and the inner circumferential surface 2B being vertically downward. The wire supply device 10 propels (biasses) the wire 2 in the linear guidance direction X by, for example, gripping the wire 2 with a pair of feed rollers (not shown) and rotating the feed roller pair. The wire 2 may be formed into a straight shape inside the wire supply device 10 using a leveler or the like. The cross-sectional shape of the wire 2 can be selected in various ways depending on the purpose, such as a square, rectangle, trapezoid, polygon, keystone shape, etc. The outer circumferential surface 2A of the wire can also be selected in various ways depending on the purpose, such as a planar shape, tapered shape, barrel shape, eccentric barrel shape, concave barrel shape, etc.

[0026] (Bending machine) The bending device 20 is positioned downstream of the wire supply device 10 in the wire passage path T and continuously bends the wire 2 into an arc shape in order to form the wire 2 into a spiral coil 90. The winding direction by this bending device 20 (the direction in which the wire 2 ultimately bends due to plastic deformation) is the positive direction ZB of the linear guide orthogonal axis Z (the downward direction in Figure 1(A)), as shown in Figure 1(A). The bending device 20 includes a base 22, a first forming roller 30, a second forming roller 40, a third forming roller 50, a pull guide 60, and a push guide 65.

[0027] The base 22 serves as a base for supporting the first molding roller 30, the second molding roller 40, the third molding roller 50, the pull guide 60, and the push guide 65. The base 22 supports the first molding roller 30, the second molding roller 40, and the third molding roller 50 in a cantilevered structure, and at the same time, the rotation axes 38, 48, and 58 of these rollers are adjustable in the forward and backward directions of the linear guide direction X and / or in the forward and reverse directions ZB of the linear guide orthogonal axis Z by a displacement mechanism (not shown).

[0028] The first forming roller 30 is the first bending-related component of the bending apparatus 20, and its first circumferential surface 32 contacts the outer circumferential surface 2A of the wire 2. In other words, the first rotation center 30C of the first forming roller 30 is located in the opposite direction ZA of the orthogonal axis Z of the linear guide rather than on the extension of the outer wire path PA of the linear guide region T1. Furthermore, if the area where the first circumferential surface 32 and the outer circumferential surface 2A of the wire are in contact is defined as the first contact region 33, then the starting end 33s of the first contact region 33 coincides with the end of the linear guide region T1. As shown in Figure 1(B), the first circumferential surface 32 is composed of the bottom surface of a circumferential groove formed on the outer circumference of the first forming roller 30, and this groove supports and guides the side surface of the wire 2, thereby suppressing twisting of the wire 2 during bending. The diameter of the first circumferential surface 32 is set to be smaller than the average coil diameter Kr. For example, the diameter of the first surface 32 is set within the range of Kr × (1 / 4) to Kr × (3 / 4).

[0029] If we define the direction in which a straight wire 2 ultimately bends to become a helical coil 90 as the "forward bending direction," and the direction in which the wire 2 bends in the opposite direction to this forward bending direction as the "reverse bending direction," then near the center point 33c of the first contact region 33 in the first forming roller 30 (near the point where the radius of curvature is smallest), the wire 2 is displaced in the reverse bending direction (primary reverse bending direction displacement).

[0030] The second forming roller 40 is the second bending-related component of the bending apparatus 20, and its second circumferential surface 42 contacts the inner circumferential surface 2B of the wire 2. Here, the second rotation center 40C of the second forming roller 40 is located in the positive direction ZB of the linear guide orthogonal axis Z, rather than on the extension of the inner wire path PB of the linear guide region T1, and at the same time, it is located forward in the linear guide direction X compared to the first rotation center 30C. Furthermore, if we define the area where the second circumferential surface 42 and the inner circumferential surface 2B of the wire as the second contact region 43, the second contact region 43 is located downstream of the first contact region 33 in the wire passage path T. Moreover, the center point 43c of the second contact region 43 extends inward ZA in the opposite direction of the linear guide orthogonal axis Z, rather than on the extension of the inner wire path PB of the linear guide region T1. Furthermore, the center point 43c extends inward ZA in the opposite direction of the linear guide orthogonal axis Z, rather than on the extension of the outer wire path PA of the linear guide region T1. As a result, the inner wire path PB in the second contact region 43 intersects both the extension of the wire center path P and the outer wire path PA in the linear guide region T1.

[0031] As shown in Figure 1(B), the second circumferential surface 42 is formed by the bottom surface of a circumferential groove formed on the outer circumference of the second forming roller 40. This groove supports and guides the side surface of the wire 2, thereby suppressing twisting of the wire 2 during bending. The diameter of the second circumferential surface 42 is set to be smaller than the average coil diameter Kr, and further smaller than the diameters of the first circumferential surface 32 and the third circumferential surface 52. For example, the diameter of the second circumferential surface 42 is set within the range of Kr × (1 / 4) to Kr × (2 / 3).

[0032] Near the center point 43c of the second contact region 43 on the second forming roller 40 (near the point where the radius of curvature is smallest), the wire 2 is displaced in the positive bending direction (secondary positive bending direction displacement). This displacement in the positive bending direction is due to the wire 2 being forcibly wrapped around the second contact region 43 by the first forming roller 30 and the third forming roller 50.

[0033] The third forming roller 50 is the third bending-related component of the bending apparatus 20, and its third circumferential surface 52 contacts the outer circumferential surface 2A of the wire 2. Here, the third rotation center 50C of the third forming roller 50 is located in the opposite direction ZA of the orthogonal axis Z of the linear guide, rather than on the extension of the outer wire path PA of the linear guide region T1, and at the same time, it is located forward in the linear guide direction X compared to the second rotation center 40C. Furthermore, if the area where the third circumferential surface 52 and the outer circumferential surface 2A of the wire are in contact is defined as the third contact region 53, then the third contact region 53 is located downstream of the wire passage path T compared to the second contact region 43. Moreover, the end 53e of the third contact region 53 approximately coincides with the extension of the inner wire path PB of the linear guide region T1.

[0034] As shown in Figure 1(B), the third circumferential surface 52 is formed by the bottom surface of a circumferential groove formed on the outer circumference of the third forming roller 50. This groove supports and guides the side surface of the wire 2, thereby suppressing twisting of the wire 2 during bending. The diameter of the third circumferential surface 52 is set to be smaller than the average coil diameter Kr. For example, the diameter of the first circumferential surface 32 is set to be smaller than the average coil diameter Kr, and is set to be within the range of Kr × (1 / 4) to Kr × (3 / 4).

[0035] In this embodiment, the diameter of the third circumferential surface 52 is made to match the diameter of the first circumferential surface 32. Also, the distance from the extension of the wire outer path PA of the linear guide region T1 at the third rotation center 50C is made to match the same distance at the first rotation center 30C.

[0036] The third contact region 53 works in cooperation with the first contact region 33 to press the wire 2 between them against the second contact region 43. As a result, the wire 2 is plastically bent in the positive bending direction within the second contact region 43. Near the center point 53c of the third contact region 53 on the third forming roller 50 (near the point where the radius of curvature is smallest), the wire 2 is displaced in a direction that reduces the curvature in the positive bending direction as a reaction to the pressing action of the wire 2 (tertiary reverse bending direction displacement). Thus, in the bending apparatus 20 of this embodiment, the wire 2 is first displaced in the reverse bending direction by the first contact region 33 of the first forming roller 30, and then the wire 2 is plastically bent in the positive bending direction within the second contact region 43 of the second forming roller 40, making it possible to suppress the amount of springback after forming.

[0037] Comparing the positions of the linear guide orthogonal axis Z at the center point 33c of the first contact region 33, the center point 43c of the second contact region 43, and the center point 53c of the third contact region 53, the center point 43c of the second contact region 43 is located furthest in the positive direction ZB. In this embodiment, since the linear guide orthogonal axis Z is set in the vertical direction, the center point 43c of the second contact region 43 is at the highest point.

[0038] Furthermore, the path range from the center point 33c of the first contact region 33, through the center point 43c of the second contact region 43, to the center point 53c of the third contact region 53 will be described in terms of a phase angle with respect to the virtual helical axis G. This phase angle range is preferably set to 120 degrees or less, more preferably to 90 degrees or less, and even more preferably to 60 degrees or less. In addition, it is preferable that the phase angle range from the center point 33c of the first contact region 33 to the center point 43c of the second contact region 43 and the phase angle range from the center point 43c of the second contact region 43 to the center point 53c of the third contact region 53 be almost identical.

[0039] The pull guide 60 is the fourth bending-related component of the bending apparatus 20, and its guide contact surface (region) 62 contacts the inner circumferential surface 2B of the wire 2. The pull guide 60 is connected to the pull guide moving mechanism 64 via an arm 63, and the position (pulling amount) of the pull guide 60 along the radial direction of the helical coil 90 can be adjusted by the pull guide moving mechanism 64. If the center point on the wire center path P at the guide contact surface 62 is defined as the pull guide center point 62c, then the pull guide center point 62c is downstream of the third contact region 53 in the wire passage path T. Furthermore, the pull guide center point 62c is on the positive ZB side of the linear guide orthogonal axis Z than on the extension of the wire inner path PB in the linear guide region T1.

[0040] The center point 62c of the pull guide is located forward of the first contact area 33 in the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z. The center point 62c of the pull guide is located forward of the second contact area 43 in the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z. The center point 62c of the pull guide is located forward of the third contact area 53 in the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z.

[0041] Furthermore, the path range from the center point 53c of the third contact region 53 to the center point 62c of the pull guide will be described in terms of a phase angle with respect to the virtual helical axis G. This phase angle range is preferably set to 90 degrees or less, and more preferably to 60 degrees or less.

[0042] The pull guide 60 plays the role of pressing the wire 2 against the third contact region 53. When the wire 2, which has already been bent in the positive bending direction in a plastic manner, is pressed against the third contact region 53, it undergoes plastic deformation such that its curvature decreases. In this embodiment, this is called the unbending process. Increasing the amount of pull by the pull guide 60 (increasing the pressing force) increases the amount of unbending in this unbending process, and decreasing the amount of pull by the pull guide 60 (decreasing the pressing force) decreases the amount of unbending in this unbending process. In this embodiment, by combining this unbending process, the curvature of the wire 2 can be finely adjusted, making it possible to suppress the amount of springback after forming the helical coil 90, and stabilizing the average coil diameter Kr of the helical coil 90. At the center point 62c of the pull guide, the wire 2 is always kept within the range of elastic deformation.

[0043] The push guide 65 is the fifth bending-related component of the bending device 20, and its push contact surface (area) 66 abuts against the outer circumferential surface 2A of the wire 2. The push guide 65 is connected to the push guide moving mechanism 68 via an arm 67, and the push guide moving mechanism 68 allows adjustment of the position (amount of push) of the push guide 65 along the radial direction of the helical coil 90. The push guide moving mechanism 68 can also retract the push guide 65, thereby moving it away from the outer circumferential surface 2A of the wire 2 (see Figure 3).

[0044] If we define the center point on the wire center path P at the pressing contact surface 66 as the pressing guide center point 66c, then the pressing guide center point 66c is located downstream of the pulling guide center point 62c in the wire passage path T.

[0045] The indentation contact surface 66 is located forward of the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z compared to the first contact area 33. The indentation contact surface 66 is located forward of the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z compared to the second contact area 43. The indentation contact surface 66 is located forward of the linear guidance direction X and on the positive ZB side of the linear guidance orthogonal axis Z compared to the third contact area 53.

[0046] Furthermore, the push guide center point 66c is located on the positive ZB side (in this case, the downward vertical side) of the orthogonal axis Z, rather than on the extension of the wire inner path PB in the linear guide region T1. On the other hand, the push guide center point 66c is located closer to the front of the linear guide direction X compared to the pull guide center point 62c.

[0047] The path range from the center point 62c of the pull guide to the center point 66c of the push guide is defined by a phase angle range with respect to the virtual helical axis G. This phase angle range is preferably set to 90 degrees or less, and more preferably to 60 degrees or less. On the other hand, the phase angle range from the center point 62c of the pull guide to the center point 66c of the push guide is preferably set to 10 degrees or more, more preferably to 18 degrees or more, and even more preferably to 25 degrees or more.

[0048] Instead of expressing it as a phase angle range, if expressed as the distance along the wire passage path T from the center point 62c of the pull guide to the center point 66c of the push guide, it is preferable to set this distance to 33.3% or less of the average circumference of the coil, more preferably to 25% or less, and even more preferably to 17% or less. On the other hand, it is preferable to set this distance to 2.7% or more of the average circumference of the coil, more preferably to 5% or more, and even more preferably to 7% or more.

[0049] Furthermore, it is preferable that the central point 66c of the push guide be positioned upstream with respect to the lower vertical end point L in the wire passage path T. Specifically, it is preferable that the central point 66c of the push guide be positioned upstream of the lower end point L by 10 degrees or more within a phase angle range, and more preferably by 15 degrees or more.

[0050] As will be explained in more detail later, this push guide 65 is protected from the influence of axial force transmitted from the wire 2 downstream toward the upstream side. This absorption effect makes it less likely for the influence of coaxial force to be transmitted to the pull guide 60 further upstream, and as a result, the amount of bending in the third reverse bending process in the third contact region 53 is always stable.

[0051] The bending region T2 in the pressing state by the pressing guide 65 extends from the starting end 33s of the first contact region 33 of the first forming roller 30 to the center point 66c of the pressing guide. In this embodiment, the bending apparatus 20 mainly performs plastic deformation in the forward bending direction in the second contact region 43 and unbending in the third contact region 53, and elastic deformation of the wire 2 in other areas, but the present invention is not limited to this. The wire 2 should ultimately be output in a state bent in the forward bending direction as a result of repeated displacement in the forward bending direction and reverse bending direction in a manner in which plastic deformation and elastic deformation are complexly mixed within the bending region T2.

[0052] (cutting device) The cutting device 300 is positioned near the lower end point L and cuts the wire 2 at any desired timing. The cutting device 300, for example, is equipped with a pair of cutting blades and cuts the wire 2 by closing the pair of cutting blades with a drive device (not shown). For example, if the target number of turns of the helical coil 90 is predetermined, the wire 2 should be cut when that target number of turns (the final turn) is reached. The new wire 2 following the cutting point becomes the first turn of the helical coil 90. The cutting method is not limited to this, and for example, cutting may be done with a cutting wheel.

[0053] (Supporting core) The support core 70 is a cylindrical or columnar rod member that is coaxially fixed to the side surface of the second forming roller 40. As a result, the support core 70 is cantilevered by the second forming roller 40 and rotates together with the second forming roller 40. As shown in Figure 2, the helical coil 90 that is led out of the bending device 20 and continuously formed will have the support core 70 wound inside it, and the upper edge of the outer circumferential surface of the support core 70 during rotation and the upper vertical edge H of the inner circumferential surface of the helical coil 90 during rotation will come into contact, thereby supporting the weight of the helical coil 90.

[0054] As shown in Figure 2(A), the diameter 72D of the support surface 72 of the support core 70 is smaller than the diameter of the second surface 42 of the second forming roller 40. As a result, the peripheral speed of the support surface 72 is smaller than the peripheral speed of the second surface 42. Since the peripheral speed of the second surface 42 is approximately equal to the feed speed of the wire 2, the peripheral speed of the inner surface of the helical coil 90 exceeds the peripheral speed of the support surface 72, and sliding resistance is generated between the two. This sliding resistance increases in proportion to the number of turns of the helical coil 90. This sliding resistance becomes an axial force transmitted upstream through the inside of the wire 2 and reaches the center point 66c of the push guide.

[0055] Furthermore, the post-processing extraction region T3 in the pressed state by the push guide 65 extends from the center point 66c of the push guide to the upper vertical edge H of the helical coil 90.

[0056] (Path detection device) The output path detection device 80 is a component that detects the current position of the wire passage path T (output region T3 after processing) of the wire 2 output from the bending device 20. In this embodiment, downstream of the pull guide 60 and the push guide 65, the probe of the output path detection device 80 is brought into contact with the outer surface 2A of the wire to detect the current position or change therein of the outer wire path PA.

[0057] If the detection point 82 is defined as the center point on the wire center path P at the location where the probe contacts the wire 2, then this detection point 82 can be selected from any location in the post-processing lead-out region T3. On the other hand, when controlling the amount of indentation of the push guide 65 using the detection result of the lead-out path detection device 80, it is preferable to bring the two as close together as possible. Specifically, if the path range from the push guide center point 66c to the detection point 82 is described in terms of a phase angle range with respect to the virtual helical axis G, it is preferable to set it to 45 degrees or less, and more preferably to 30 degrees or less. If described with respect to the pull guide center point 62c, it is preferable to set the phase angle range with respect to the virtual helical axis G from the pull guide center point 62c to the detection point 82 to 90 degrees or less, and more preferably to 60 degrees or less. On the other hand, if the same phase angle range from the pull guide center point 62c to the detection point 82 is set to 10 degrees or more, more preferably to 18 degrees or more, and more preferably to 25 degrees or more.

[0058] Furthermore, it is preferable that the detection point 82 is positioned upstream of the lower vertical end point L in the wire passage path T. Specifically, it is preferable that the detection point 82 is positioned upstream of the lower end point L by 10 degrees or more in a phase angle range, and more preferably by 15 degrees or more.

[0059] (Control device) As shown in Figure 3(A), the control device 85 is a so-called computer and includes a CPU 851, RAM 852, ROM 853, input device 854, display device 855, power supply 857, input / output interface 858, and bus 859.

[0060] The CPU 851 is the so-called central processing unit, and various programs are executed to realize various functions. The RAM 852 is so-called RAM (Random Access Memory) and is used as the CPU 851's workspace. The ROM 853 is so-called ROM (Read-Only Memory) and stores the basic OS and various programs (for example, measurement programs) executed by the CPU 851.

[0061] The input device 854 includes buttons, touch panel input keys, a keyboard, and a mouse, which are used to input various types of information. The display device 855 is a display that shows various measurement progress and measurement results.

[0062] The power supply 857 supplies power for the operation of each component. The input / output interface 858 is connected to the pull guide movement mechanism 64, the push guide movement mechanism 68, and the output path detection device 80, and receives detection signals from the output path detection device 80, as well as outputting control signals to control the pull guide movement mechanism 64 and the push guide movement mechanism 68. The bus 859 is a wiring system that connects the CPU 851, RAM 852, ROM 853, input device 854, display device 855, power supply 857, input / output interface 858, etc., as an integrated unit for communication.

[0063] When the basic OS and various programs (control programs) stored in ROM 853 are executed by CPU 851, the functional blocks shown in Figure 3(B) are implemented. Specifically, the control device 85 has a non-indentation path measurement unit 860, an indentation amount calculation unit 870, and a pull amount calculation unit 880 as functional blocks. The manufacturing procedure for the spiral coil 90 using the spiral wire manufacturing apparatus 1 will be described below, incorporating these functions.

[0064] (Effect of sliding resistance on the average diameter of the coil) First, we will explain the effect of sliding resistance between the support core 70 and the helical coil 90 when manufacturing the helical coil 90. Figure 4 shows the case when the helical wire manufacturing apparatus 1 manufactures the helical coil 90 with the push guide 65 separated from the outer surface 2A of the wire (a state assuming that the push guide 65 does not exist / hereinafter referred to as the non-pushed state). Note that the amount of pull by the pull guide 60 must be set in advance, and the method of setting this will be described later.

[0065] As shown in Figure 4(A), in the first winding step, before the tip 2s of the wire 2 contacts the support core 70, the sliding resistance between the support core 70 and the wire 2 is zero. In this way, the wire passage path W in the first winding step, with the push guide 65 separated from the outer surface 2A of the wire (or formally in contact but without applying external force), is defined as the "initial non-pushed wire passage path W(1)". Furthermore, the linear guide region W1 in the initial non-pushed wire passage path W(1) is defined as the "initial non-pushed linear guide region W1(1)", the bending region W2 in the initial non-pushed wire passage path W(1) is defined as the "initial non-pushed bending region W2(1)", and the post-processing lead-out region W3 in the initial non-pushed wire passage path W(1) is defined as the "initial non-pushed post-processing lead-out region W3(1)". In the non-pressed state, the initial bending region W2(1) is from the starting end 33s of the first contact region 33 of the first forming roller 30 to the center point 62c of the pull guide. Also, in the non-pressed state, the exit region W3(1) after the initial processing is from the center point 62c of the pull guide to the upper vertical edge H of the inner circumferential surface of the helical coil 90.

[0066] Here, the non-indentation path measuring unit 860 in the control device 85 measures the wire outer path PA in the non-indentation first processing output region W3(1) using the output path detection device 80. While this example illustrates the non-indentation path measuring unit 860 measuring the first wire outer path PA, the present invention is not limited to this. It may also measure any wire outer path PA selected from the initial few turns (e.g., the initial five turns) where the influence of sliding resistance is small, or calculate the average position of the wire outer paths PA for the initial few turns (e.g., the initial five turns).

[0067] As shown in Figure 4(B), if the winding process progresses for the nth time (n>1) while the coil remains in a non-pressed state, the sliding resistance between the inner surface of each winding and the support core 70 increases. Moreover, the sliding resistance increases in conjunction with the increase in the number of windings. In this embodiment, the peripheral speed of the inner surface of the helical coil 90 exceeds the peripheral speed of the support surface 72, so this sliding resistance becomes an axial force J that biases the helical coil 90 from the downstream side to the upstream side, transmitting the wire 2 towards the pull guide 60. Since this axial force J is a reaction force to the thrust force S in the feeding direction by the wire supply device 10, the post-processing exit region W3(n) in the nth wire passage path W(n) is displaced radially outward compared to the first post-processing exit region W3(1) when the coil is not pressed. In other words, the radius of curvature of the post-processing exit region W3(n) increases. This radius of curvature increases as the number of windings (n) increases.

[0068] The outward displacement (increase in radius of curvature) of the post-processing derived region W3(n) is within the range of elastic deformation for the wire 2. However, the amount of tension of the pull guide 60 relative to the initial wire passage path W(1) when not indented decreases relatively when compared to the nth (n>1) wire passage path W(n). This decrease in tension increases as the number of turns increases.

[0069] As already mentioned, the reduction in the amount of tension reduces the pressing force required to press the wire 2 against the third contact area 53 of the third forming roller 50, and ultimately reduces the amount of unbending in the unbending process in the third contact area 53. As a result, the unit coil diameter K(n) for each turn (n) decreases as the number of turns increases.

[0070] (Introduction of verification cases) Figure 5 shows the manufacturing status of the spiral coil 90 by the spiral wire manufacturing apparatus 1 with the push guide 65 separated from the outer surface 2A of the wire. The wire 2 used was made of stainless steel equivalent to SUS410, with an axial length of 1.2 mm and a radial length of 2.7 mm. The coil average diameter Kr was adjusted to a target value of 88 mm. For the arrangement of the derivation path detection device 80, the phase angle from the center point 62c of the pull guide to the detection point 82 was set to 60 degrees. Also, in Figure 5, for convenience, the average value of each value from the 1st to the 10th winding is expressed as the "1st wire" value, the average value of each value from the 46th to the 55th winding is expressed as the "50th wire" value, and the average value of each value from the 91st to the 100th winding is expressed as the "100th wire" value.

[0071] Figure 5(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.057 mm and the detection position at the "100th wire" is 0.078 mm. In other words, it can be seen that as the number of turns increases (i.e., as time passes), the outer wire path PA gradually displaces outward (towards the positive side). Figure 5(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "1st wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount relative to the "1st wire". The diameter change amount at the "50th wire" is -0.017 mm and the diameter change amount at the "100th wire" is -0.027 mm. In other words, as the number of turns increases, the unit coil diameter K(n) of each turn gradually decreases.

[0072] (Manufacturing method for spiral coils using a push guide)

[0073] Next, a method for manufacturing a helical coil 90 while bringing the push guide 65 into contact with the outer surface 2A of the wire will be described. Figure 6 shows the case in which the helical wire manufacturing apparatus 1 manufactures a helical coil 90 by bringing the push guide 65 into contact with the outer surface 2A of the wire.

[0074] Figure 6(A) is substantially the same as the state in Figure 4(A), and is the state before the push guide 65 is brought into contact with the outer surface 2A of the wire (non-pushed state). The pull amount calculation unit 880 calculates the pull amount of the pull guide 60 and, in the non-pushed state, sets the position of the pull guide 60 in advance using the pull guide moving mechanism 64. The pull amount of the pull guide 60 is set so that the average coil diameter Kr of the manufactured helical coil 90 becomes the final target diameter Km. In this embodiment, however, a virtual target diameter Kb smaller than the final target diameter Km is adopted as the target value, and the pull amount is calculated and controlled so that this virtual target diameter Kb is achieved in the "non-pushed state". Specifically, it is preferable to set the virtual target diameter Kb to a value (Km-E) that is smaller than the final target diameter Km by the amount of diameter increase (E) due to the effect of the push amount E described later. In other words, the amount of tension required to achieve the virtual target diameter Kb in a non-contracted state is smaller than the amount of tension required to achieve the final target diameter Km in a non-contracted state.

[0075] Thus, the reason for adopting a virtual target diameter Kb and setting the pulling amount to a small value in advance is that the pulling amount increases retrospectively (relatively) due to the amount of indentation in the pushing operation described later.

[0076] Next, the indentation amount calculation unit 870 in the control device 85 calculates an indentation amount such that the guide contact surface 62 of the indentation guide 65 is at the same position as the wire outer path PA in the non-indentation initial processing output region W3(1) measured by the non-indentation path measurement unit 860 in Figure 6(A), or is located radially inward in terms of the radius of curvature (or coil radius of the helical coil 90), and transmits a control signal to the indentation guide moving mechanism 68 to realize that indentation amount, thereby causing the indentation guide 65 to advance (indent) as shown in Figure 6(B).

[0077] The specific amount of indentation in this embodiment will now be explained. In Figure 6(A), if Mp is the radius of curvature of the wire outer path PA of the future indentation contact surface 66 in the derivation region W3(1) after the initial processing when not indented, the indentation amount calculation unit 870 is set to be Mp × 0.001 or more. Preferably, the indentation amount calculation unit 870 is set to be Mp × 0.002 or more. On the other hand, the indentation amount calculation unit 870 is set to be Mp × 0.05 or less. Note that the radius of curvature Mp used in the calculation can also be estimated and applied by analogy to half the value of the average coil diameter Kr, which is the target value in the bending process.

[0078] As a specific control method for the indentation guide movement mechanism 68 by the indentation amount calculation unit 870, as shown in Figure 6(B), the indentation guide movement mechanism 68 advances the indentation guide 65 while measuring the position of the wire outer path PA with the derivation path detection device 80, bringing it into initial contact with the wire outer path PA. This initial contact can be detected by the minute fluctuation of the wire outer path PA in the detection signal of the derivation path detection device 80. Starting from the position of the indentation guide 65 at the time of this initial contact, the indentation guide 65 is advanced only by the amount equivalent to the calculated indentation amount. Alternatively, as another control method, the indentation guide movement mechanism 68 may advance the indentation guide 65 until the wire outer path PA is displaced radially inward by the amount equivalent to the calculated indentation amount while measuring the position of the wire outer path PA with the derivation path detection device 80. In this case, it is preferable to bring the derivation path detection device 80 and the indentation guide 65 closer together.

[0079] In this embodiment, the control device 85 controls the push-in guide movement mechanism 68 as an example, but the present invention is not limited thereto. An operator may adjust the amount of push-in by visually operating the push-in guide movement mechanism 68. In this case, it is preferable that the push-in guide movement mechanism 68 is equipped with a gauge that can display the amount of push-in.

[0080] To reiterate, as a result of the pushing operation by the pushing guide 65, the initial processing exit region T3(1) (in the pushed state) is displaced radially inward. This wire passage path T is used to manufacture the helical coil 90.

[0081] As shown in Figure 7, when the helical coil 90 is manufactured in a pressed state by the push guide 65, sliding resistance accumulates between the inner surface of each winding and the support core 70 as the number of turns (n) increases. This sliding resistance becomes an axial force J that biases the helical coil 90 from the downstream side to the upstream side, and is transmitted through the wire 2 to the push guide 65. Since this axial force J is a reaction force to the thrust force S in the feeding direction by the wire supply device 10, the wire passage path T tends to be displaced radially outward. However, because the push guide 65 restricts the outward displacement at the push guide center point 66c, the radial outward displacement is limited to the post-processing output region T3(n) downstream of the push guide center point 66c. Downstream of the push guide center point 66c, even if the post-processing output region T3(n) is displaced outward, the actual amount of pull by the pull guide 60 hardly changes. As a result, the pressing force required to press the wire 2 against the third contact area 53 of the third forming roller 50 is always stable, so the amount of unbending in the unbending process in the third contact area 53 remains constant, and the unit coil diameter K(n) for each winding (n) can always be kept stable.

[0082] Once the target number of turns is reached, the wire 2 is cut by the cutting device 300 to complete the helical coil 90. Then, for example as shown in Figure 13(A), the helical coil 90 is cut and divided along its main wire using the cutting grinding wheel of the dividing device 400. As a result, as shown in Figure 13(B), a piston ring 500 with a single winding and a C-shaped structure in which part of the ring is divided can be obtained. The entire system combining the helical wire manufacturing device 1 and the dividing device 400 can be defined as a piston ring manufacturing device.

[0083] (Example 1) Figures 8 to 10 show the results of manufacturing a spiral coil 90 using the spiral wire manufacturing apparatus 1 with the outer surface 2A of the wire pressed in by the pressing guide 65 (pressed state), following the procedure shown in Figures 6 and 7. The wire 2 used was made of stainless steel equivalent to SUS410, with an axial length of 1.2 mm and a radial length of 2.7 mm. The pulling and pressing amounts were adjusted so that the final target diameter Km of the average coil diameter Kr was 88 mm. In Figures 8 to 10, for convenience, the average value of each value from the 1st to the 10th turn is expressed as the "1st wire" value, the average value of each value from the 46th to the 55th turn is expressed as the "50th wire" value, and the average value of each value from the 91st to the 100th turn is expressed as the "100th wire" value.

[0084] In Example 1, the phase angle between the center point 62c of the pull guide and the center point 66c of the push guide was set to 40 degrees for the placement of the push guide 65. Additionally, the phase angle between the center point 62c of the pull guide and the detection point 82 of the output path detection device 80 was set to 60 degrees.

[0085] Figure 8 shows the data when the indentation amount is set to 0.2 mm. Figure 8(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.040 mm and the detection position at the "100th wire" is 0.063 mm. In other words, it can be seen that the outer wire path PA gradually displaces outward as the number of turns increases (i.e., as time passes). On the other hand, Figure 8(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "1st wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount based on the "1st wire". The diameter change amount at the "50th wire" is +0.008 mm and the diameter change amount at the "100th wire" is +0.009 mm. In other words, even as the number of turns increases, the change in the unit coil diameter K(n) of each turn is suppressed and remains almost constant.

[0086] Figure 9 shows the data when the indentation amount is set to 0.5 mm. Figure 9(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.034 mm and the detection position at the "100th wire" is 0.062 mm. In other words, it can be seen that as the number of turns increases (i.e., as time passes), the outer wire path PA gradually displaces outward. On the other hand, Figure 9(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "1st wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount based on the "1st wire". The diameter change amount at the "50th wire" is +0.001 mm and the diameter change amount at the "100th wire" is +0.018 mm. In other words, even as the number of turns increases, the change in the unit coil diameter K(n) of each turn is suppressed and remains almost constant.

[0087] Figure 10 shows the data when the indentation amount is set to 1.0 mm. Figure 10(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.044 mm and the detection position at the "100th wire" is 0.074 mm. In other words, it can be seen that the outer wire path PA gradually displaces outward as the number of turns increases (i.e., as time passes). On the other hand, Figure 10(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "1st wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount with the "1st wire" as the reference. The diameter change at the 50th turn is +0.003 mm, and the diameter change at the 100th turn is +0.000 mm. In other words, even as the number of turns increases, the diameter change of the unit coil diameter K(n) for each turn is suppressed and remains almost constant.

[0088] (Example 2) Figures 11 and 12 show the results of manufacturing a spiral coil 90 using the spiral wire manufacturing apparatus 1, with the outer surface 2A of the wire pressed in by the pressing guide 65 (pressed state), following the procedure shown in Figures 6 and 7. The wire 2 used was made of stainless steel equivalent to SUS410, with an axial length of 1.2 mm and a radial length of 2.7 mm. The pulling and pressing amounts were adjusted so that the final target diameter Km of the average coil diameter Kr was 88 mm. In Figures 11 and 12, for convenience, the average value of each value from the 1st to the 10th turn is expressed as the "1st wire" value, the average value of each value from the 46th to the 55th turn is expressed as the "50th wire" value, and the average value of each value from the 91st to the 100th turn is expressed as the "100th wire" value.

[0089] In Example 2, the phase angle between the center point 62c of the pull guide and the center point 66c of the push guide was set to 30 degrees for the placement of the push guide 65. Also, the phase angle between the center point 62c of the pull guide and the detection point 82 of the output path detection device 80 was set to 65 degrees.

[0090] Figure 11 shows the data when the indentation amount is set to 0.2 mm. Figure 11(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.046 mm and the detection position at the "100th wire" is 0.113 mm. In other words, it can be seen that the outer wire path PA gradually displaces outward as the number of turns increases (i.e., as time passes). On the other hand, Figure 11(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "first wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount with the "first wire" as the reference. The diameter change at the 50th turn is +0.000 mm, and the diameter change at the 100th turn is -0.011 mm. In other words, even as the number of turns increases, the diameter change of the unit coil diameter K(n) for each turn is suppressed and remains almost constant.

[0091] Figure 12 shows the data when the indentation amount is set to 0.5 mm. Figure 12(A) shows the results of measuring the outer wire path PA during manufacturing using the derivation path detection device 80. Taking the detection position of the "first wire" as the reference (0 mm) and the direction in which the outer wire path PA is displaced outward as the positive value, the detection position at the "50th wire" is 0.052 mm and the detection position at the "100th wire" is 0.083 mm. In other words, it can be seen that the outer wire path PA gradually displaces outward as the number of turns increases (i.e., as time passes). On the other hand, Figure 12(B) shows the results of measuring and calculating the unit coil diameter K(n) of the "1st wire", "50th wire", and "100th wire" in the manufactured helical coil, and further calculating the diameter change amount with the "1st wire" as the reference. The diameter change at the 50th turn is +0.013 mm, and the diameter change at the 100th turn is +0.018 mm. In other words, even as the number of turns increases, the diameter change of the unit coil diameter K(n) for each turn is suppressed and remains almost constant.

[0092] In this embodiment, the sliding resistance between the inner surface of the helical coil 90 and the support core 70 becomes an axial force J (reaction force component to the thrust force S) transmitted to the upstream side of the wire 2, and the push guide 65 suppresses the adverse effect of this axial force J on the reverse bending of the third forming roller 50. However, the present invention is not limited to this. For example, even if an axial force acting in the same direction as the thrust force S acts on the helical coil 90 side, the push guide 65 can suppress its adverse effect. Also, for example, even if some external force acts on the wire 2 in the post-processing lead-out region T3, the push guide 65 can suppress its adverse effect.

[0093] Furthermore, while this embodiment illustrates the use of stainless steel equivalent to SUS410 as the wire material, the present invention is not limited thereto. For example, spring materials such as carbon steel wire, hard steel wire, piano wire, spring steel wire, carbon steel oil-tempered wire, chromium-vanadium steel oil-tempered wire, silicon-chromium steel oil-tempered wire, and silicon-chromium-vanadium steel oil-tempered wire are suitably used. In addition, the material of the wire used when manufacturing piston rings can be any material that can be made into wire, and can be any material that has been conventionally used for piston rings, such as ferrous metals and non-ferrous metals. For example, carbon steel, alloy steel, hardened steel, high-speed tool steel, stainless steel, aluminum alloy, magnesium alloy, titanium alloy, etc. Specifically, martensitic stainless steel, chromium-manganese steel (SUP9 material), chromium-vanadium steel (SUP10 material), silicon-chromium steel (SWOSC-V material), and hard steel wire (SWRH62B material) are suitably used.

[0094] Furthermore, while this embodiment illustrates the case where a helical coil is used as a material for manufacturing a piston ring, the present invention is not limited thereto, and helical coils can be used as a material for other ring-shaped structures. Moreover, the helical coil itself can be applied to structures such as coil springs. The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. [Explanation of Symbols]

[0095] 1 Spiral wire manufacturing equipment 2 wire rod 2A Wire outer circumferential surface 2B Wire inner circumferential surface 10 Wire feeding device 20 Bending machine 22 base 30 First forming roller 32 First peripheral surface 33 First contact area 40 Second forming roller 42 Second peripheral surface 43 Second contact area 50 Third forming roller 52 Third peripheral surface 53 Third contact area 60 Pull Guide 62 Guide contact surface 64 Pull Guide Movement Mechanism 65 Push-in guide 66 Push-in contact surface 68 Push-in guide movement mechanism 70 Support core 72 Support circumferential surface 80. Derivation path detection device 82 detection points 85 Control device 90 spiral coils 300 cutting equipment 400 splitting device 500 Piston Rings E amount of indentation G Virtual spiral axis H Vertical upper edge K unit coil diameter Kb virtual target diameter Km Final target diameter Kr coil average diameter L lower end point Mp radius of curvature P Wire Center Pass PA wire outer path PA area wire outer path PB wire inner path S propulsion force T Wire passage route T1 Linear guidance area T2 Bending area T3 Derived area after processing X Straight-line guidance direction Z-line guide orthogonal axis

Claims

1. A wire supply device that supplies straight, metallic wires, A bending device is positioned downstream of the wire supply device and bends the wire into an arc shape, A support core that supports the inner circumferential surface of the wire that becomes a helical coil after passing through the bending device, Equipped with, When defining the outer surface of the helical coil in the wire as the outer surface of the wire and the inner surface of the helical coil as the inner surface of the wire, and defining the imaginary line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position), The bending apparatus described above is A first forming roller that contacts the outer surface of the wire supplied from the wire supply device, A second molding roller that contacts the inner surface of the wire downstream of the wire center path from the contact area between the first molding roller and the outer surface of the wire (hereinafter referred to as the first contact area), A third molding roller that contacts the outer surface of the wire downstream of the wire center path from the contact area between the second molding roller and the inner surface of the wire (hereinafter referred to as the second contact area), A pull guide that contacts the inner surface of the wire downstream of the wire center path from the contact area between the third forming roller and the outer surface of the wire (hereinafter referred to as the third contact area), The system includes a push guide that contacts the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area), In the aforementioned pull guide contact region, the wire is displaced within the range of elastic deformation. A spiral wire manufacturing apparatus characterized by the following features.

2. A wire supply device that supplies straight, metallic wires, A bending device is positioned downstream of the wire supply device and bends the wire into an arc shape, A support core that supports the inner circumferential surface of the wire that becomes a helical coil after passing through the bending device, Equipped with, When defining the outer surface of the helical coil in the wire as the outer surface of the wire and the inner surface of the helical coil as the inner surface of the wire, and defining the imaginary line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position), The bending apparatus described above is A first forming roller that contacts the outer surface of the wire supplied from the wire supply device, A second molding roller that contacts the inner surface of the wire downstream of the wire center path from the contact area between the first molding roller and the outer surface of the wire (hereinafter referred to as the first contact area), A third molding roller that contacts the outer surface of the wire downstream of the wire center path from the contact area between the second molding roller and the inner surface of the wire (hereinafter referred to as the second contact area), A pull guide that contacts the inner surface of the wire downstream of the wire center path from the contact area between the third forming roller and the outer surface of the wire (hereinafter referred to as the third contact area), The system includes a push guide that contacts the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area), In the contact area between the push guide and the outer surface of the wire (hereinafter referred to as the push guide contact area), the wire is displaced within the range of elastic deformation. A spiral wire manufacturing apparatus characterized by the following features.

3. When defining the direction in which the wire bends to form the helical coil as the forward bending direction, and the direction in which the wire bends in the opposite direction to the forward bending direction as the reverse bending direction, The first and third contact regions press the wire against the second contact region, causing the wire to be displaced in the reverse bending direction in the first contact region and in the forward bending direction in the second contact region. A spiral wire manufacturing apparatus according to claim 1 or 2.

4. The wire outer path is defined as the virtual line along the outer surface of the wire in the wire passage path from the wire supply position in the wire supply device to the core contact position. Assuming that the push guide does not come into contact with the outer surface of the wire, and defining the outer wire path defined in the first winding of the wire as the initial outer wire path when not pushed, The contact area between the push guide and the outer surface of the wire (hereinafter referred to as the push guide contact area) is set at the same position as the initial outer wire path when not pushed, or radially inward in terms of the radius of curvature from the initial outer wire path when not pushed. A spiral wire manufacturing apparatus according to claim 1 or 2.

5. The aforementioned indentation guide contact area is characterized in that it is set at a location at least 0.1% of the radius of curvature, radially inward from the initial wire outer path when not indented, with respect to the radius of curvature. The spiral wire manufacturing apparatus according to claim 4.

6. The distance along the wire center path from the center point on the wire center path in the pull guide contact area (hereinafter referred to as the pull guide center point) to the center point on the wire center path in the contact area between the push guide and the outer surface of the wire (hereinafter referred to as the push guide contact area) (hereinafter referred to as the push guide center point) is set to 2.7% or more of the circumference of one rotation of the center line of the wire in the helical coil. A spiral wire manufacturing apparatus according to claim 1 or 2.

7. The distance along the wire center path from the center point on the wire center path in the pull guide contact area (hereinafter referred to as the pull guide center point) to the center point on the wire center path in the contact area between the push guide and the outer surface of the wire (hereinafter referred to as the push guide contact area) (hereinafter referred to as the push guide center point) is set to 33.3% or less of the circumference of one rotation of the center line of the wire in the helical coil. A spiral wire manufacturing apparatus according to claim 1 or 2.

8. The device is characterized by comprising a path detection device that detects the displacement of the wire passage path downstream of the bending device. A spiral wire manufacturing apparatus according to claim 1 or 2.

9. The aforementioned helical coil is characterized by being made of a material for piston rings. A spiral wire manufacturing apparatus according to claim 1 or 2.

10. A spiral wire manufacturing apparatus according to claim 9, A splitting device for cutting the aforementioned helical coil and dividing it into single-winding piston ring members, A piston ring manufacturing apparatus characterized by comprising the following features.

11. A wire supply device supplies straight, metallic wires. The wire is bent into an arc shape by a bending device located downstream of the wire supply device. The inner circumferential surface of the wire, which becomes a helical coil after passing through the bending device, is supported by a support core. When defining the outer surface of the helical coil in the wire as the outer surface of the wire and the inner surface of the helical coil as the inner surface of the wire, and defining the imaginary line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position), In the aforementioned bending apparatus, The first forming roller is brought into contact with the outer surface of the wire supplied from the wire supply device. The second molding roller is brought into contact with the inner surface of the wire at a point downstream of the wire center path from the contact area between the first molding roller and the outer surface of the wire (hereinafter referred to as the first contact area). The third molding roller is brought into contact with the outer surface of the wire at a point downstream of the wire center path from the contact area between the second molding roller and the inner surface of the wire (hereinafter referred to as the second contact area). The pull guide is brought into contact with the inner surface of the wire at a point downstream of the wire center path from the contact area between the third forming roller and the outer surface of the wire (hereinafter referred to as the third contact area). The push guide is brought into contact with the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area), In the aforementioned pull guide contact region, the wire is displaced within the range of elastic deformation. A method for manufacturing a spiral wire, characterized by the following features.

12. A wire supply device supplies straight, metallic wires. The wire is bent into an arc shape by a bending device located downstream of the wire supply device. The inner circumferential surface of the wire, which becomes a helical coil after passing through the bending device, is supported by a support core. When defining the outer surface of the helical coil in the wire as the outer surface of the wire and the inner surface of the helical coil as the inner surface of the wire, and defining the imaginary line along the center line of the wire in the wire passage path from the wire supply position in the wire supply device to the position where the wire contacts the support core (hereinafter referred to as the core contact position), In the aforementioned bending apparatus, The first forming roller is brought into contact with the outer surface of the wire supplied from the wire supply device. The second molding roller is brought into contact with the inner surface of the wire at a point downstream of the wire center path from the contact area between the first molding roller and the outer surface of the wire (hereinafter referred to as the first contact area). The third molding roller is brought into contact with the outer surface of the wire at a point downstream of the wire center path from the contact area between the second molding roller and the inner surface of the wire (hereinafter referred to as the second contact area). The pull guide is brought into contact with the inner surface of the wire at a point downstream of the wire center path from the contact area between the third forming roller and the outer surface of the wire (hereinafter referred to as the third contact area). The push guide is brought into contact with the outer surface of the wire downstream of the wire center path from the contact area between the pull guide and the inner surface of the wire (hereinafter referred to as the pull guide contact area), In the contact area between the push guide and the outer surface of the wire (hereinafter referred to as the push guide contact area), the wire is displaced within the range of elastic deformation. A method for manufacturing a spiral wire, characterized by the following features.

13. A piston ring manufacturing method characterized by dividing the helical coil manufactured by the helical wire manufacturing method of claim 11 or 12 into single windings to form a piston ring member.

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