Rod manufacturing method

Abstract

To provide a manufacturing method of a rod capable of suppressing a decrease in productivity.SOLUTION: In a manufacturing method of a rod 11 for plating a rod 11 having a large diameter part 20 and a small diameter part 21 located at an end and having a smaller diameter than the large diameter part 20, masking jig 61 is used which includes a metal substrate part 81 having a contact part that contacts an end part 32 of the small diameter part 21 and an insulating part 82 covering the substrate part 81 and the small diameter part 21 and having a hole part 75 at a position facing the end part 32, so as to bring a plating solution F into contact with the rod 11 by flowing the plating solution F from a large diameter part 20 side to a small diameter part 21 side.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a rod. [Background technology]

[0002] There is a technology for controlling the flow of current in a plating bath by providing an insulating member and a hole through which the insulating member passes, and arranging the part requiring plating to face the hole in the insulating member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-214765 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when plating a rod, it is required to suppress a decrease in productivity.

[0005] Therefore, an object of the present invention is to provide a rod manufacturing method that can suppress a decrease in productivity. [Means for solving the problem]

[0006] In order to achieve the above object, a first aspect of the present invention is a method for manufacturing a rod, which plating is performed on a rod having a large diameter portion and a small diameter portion that is smaller in diameter than the large diameter portion and is located at an end, and which uses a masking jig including a metal substrate portion having a contact portion that contacts the end of the small diameter portion, and an insulating portion that covers the substrate portion and the small diameter portion and has a hole in a position opposite the end, and which causes plating solution to come into contact with the rod by flowing it from the large diameter portion side to the small diameter portion side. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress a decrease in productivity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a rod to be plated by a rod manufacturing method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view showing a masking jig used in the rod manufacturing method according to the embodiment of the present invention. [Figure 3] 1 is a front view showing a masking jig used in a rod manufacturing method according to an embodiment of the present invention and a cross section of a portion of the rod before the masking jig is attached. FIG. [Figure 4] 1 is a partial front view showing a state in which a masking jig used in a rod manufacturing method according to an embodiment of the present invention is attached to a rod. FIG. [Figure 5] 1 is a cross-sectional view schematically showing a manufacturing apparatus used in a rod manufacturing method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0010] First, a rod 11 manufactured by the manufacturing method of the embodiment will be described with reference to FIG. The rod 11 is made of metal and is a substantially cylindrical bar-like member that extends long in one direction. The rod 11 has a through-hole 12 formed in the center in the radial direction, which penetrates through in the axial direction.

[0011] The rod 11 has a main shaft portion 20 (large diameter portion), a first shaft portion 21 (small diameter portion), and a second shaft portion 22. The main shaft portion 20 is cylindrical. The outer peripheral surface portion 20a of the main shaft portion 20 is a cylindrical surface on its radially outer side. The main shaft portion 20 has a first end surface portion 20b at one axial end and a second end surface portion 20c at the other axial end. The first end surface portion 20b and the second end surface portion 20c are both flat surfaces that extend perpendicular to the central axis of the outer peripheral surface portion 20a.

[0012] First shank 21 extends from first end face portion 20b of main shank 20 along the axial direction of main shank 20. First shank 21 is located at one axial end of rod 11. First shank 21 is substantially cylindrical, and its outer diameter is smaller than the outer diameter of main shank 20 over its entire axial length. First shank 21 has a base end shank 31 and a tip end shank 32 (end portion).

[0013] The base end shank 31 is located on the axial side of the first shank 21 toward the main shank 20, and extends from the first end surface 20b of the main shank 20 along the axial direction of the main shank 20. The base end shank 31 is cylindrical. The outer peripheral surface 31a of the base end shank 31 on its radially outer side forms a cylindrical surface. The base end shank 31 has an end surface 31b at the end opposite the main shank 20 in the axial direction. The end surface 31b is flat and extends perpendicular to the central axis of the outer peripheral surface 31a.

[0014] The distal end shank 32 is located at the end of the first shank 21 opposite to the main shank 20 in the axial direction, and has a threaded shank 41 and a tip end portion 42.

[0015] The threaded shank 41 is located on the axial side of the distal shank 32 toward the base end shank 31, and extends from the end face 31b of the base end shank 31 along the axial direction of the base end shank 31. The threaded shank 41 is substantially cylindrical, and its outer diameter is smaller than the outer diameter of the base end shank 31 over its entire axial length. A male thread 45 is formed on the outer periphery of the threaded shank 41. The threaded shank 41 has an end face 41a at the end opposite the base end shank 31 in the axial direction. The end face 41a is flat and extends perpendicular to the central axis of the male thread 45.

[0016] The most distal end portion 42 is located on the axially opposite side of the distal shank portion 32 from the base end shank portion 31, and constitutes one end of the rod 11 in the axial direction. The most distal end portion 42 extends from the end face portion 41a of the threaded shank portion 41 along the axial direction of the threaded shank portion 41. The most distal end portion 42 is substantially cylindrical, and its outer diameter is smaller than the diameter of the thread bottom of the threaded shank portion 41 over its entire axial length. The most distal end portion 42 has outer peripheral surface portions 42a and 42b on the radially outer side. The outer peripheral surface portion 42a has a cylindrical surface and extends from the inner peripheral edge of the end face portion 41a along the axial direction of the threaded shank portion 41. The outer peripheral surface portion 42b has a tapered surface and extends from the edge of the outer peripheral surface portion 42a opposite the end face portion 41a in the axial direction of the outer peripheral surface portion 42a along the axial direction of the outer peripheral surface portion 42a. The outer diameter of the outer peripheral surface portion 42b decreases as it moves away from the outer peripheral surface portion 42a in the axial direction. The most distal end portion 42 has a distal end surface portion 42c at the end opposite to the threaded shaft portion 41 in the axial direction. The distal end surface portion 42c is flat and extends perpendicular to the central axis of the outer peripheral surface portions 42a, 42b. The distal end surface portion 42c forms the distal end surface on one axial side of the rod 11. The distal end surface portion 42c, the end surface portion 41a, the end surface portion 31b, and the first end surface portion 20b are parallel to each other.

[0017] Second shank 22 extends from second end face 20c of main shank 20 along the axial direction of main shank 20. Second shank 22 is located at the other end of rod 11 opposite first shank 21. Second shank 22 is substantially cylindrical, and its outer diameter is smaller than the outer diameter of main shank 20 over its entire axial length. Second shank 22 has a base end shank 51 and a threaded shank 52.

[0018] Base end shaft portion 51 is located on the axial side of second shaft portion 22 toward main shaft portion 20, and extends from second end surface portion 20c of main shaft portion 20. Base end shaft portion 51 is cylindrical. Outer peripheral surface portion 51a on the radially outer side of base end shaft portion 51 forms a cylindrical surface.

[0019] The threaded shank 52 is located on the opposite side of the second shank 22 from the main shank 20 in the axial direction, and forms the other end opposite the most distal end 42 of the rod 11 in the axial direction. The threaded shank 52 is substantially cylindrical, and has a male thread 55 formed on its outer periphery. The threaded shank 52 has a distal end surface 52a at the end opposite the base end shank 51 in the axial direction. The distal end surface 52a is flat and extends perpendicular to the central axis of the male thread 55, and is parallel to the second end surface 20c. The distal end surface 52a forms the distal end surface of the rod 11 opposite the distal end surface 42c in the axial direction. In the rod 11, one end of a through hole 12 opens at the radial center of the distal end surface 42c, and the other end of the through hole 12 opens at the radial center of the distal end surface 52a.

[0020] The rod 11 constitutes a cylinder device. The cylinder device is, for example, a shock absorber used in a suspension device for a vehicle such as an automobile or a railroad car. The cylinder device includes the rod 11, a cylinder into which the rod 11 is inserted (not shown), a piston connected to the rod 11 and slidably disposed within the cylinder, a rod guide disposed in an opening of the cylinder to support the rod 11, and a sealing member that closes the gap between the opening of the cylinder and the rod. The piston is fitted to the base end shaft portion 31 of the rod 11. A nut for fixing the piston to the rod 11 is threadedly engaged with the male threads 45 of the threaded shaft portion 41 of the rod 11. The rod 11 slides over the rod guide and the sealing member in the main shaft portion 20. A nut for connecting the rod 11 to the vehicle body is threadedly engaged with the male threads 55 of the threaded shaft portion 52 of the rod 11.

[0021] In rod 11, second end face portion 20c of main shaft portion 20, outer peripheral surface portion 51a, male thread 55, and tip surface portion 52a of second shank portion 22, all of which are on the side attached to the vehicle body, are non-plated region A1. Furthermore, in rod 11, male thread 45 of threaded shank portion 41 is non-plated region A2. Furthermore, in rod 11, outer peripheral surface portion 42a of distal end portion 42 is plated region B, which is plated. Furthermore, in rod 11, outer peripheral surface portion 42b of distal end portion 42 is region C, which may or may not be plated. Furthermore, in rod 11, outer peripheral surface portion 20a and first end face portion 20b of main shaft portion 20, and outer peripheral surface portion 31a of base end shank portion 31 are plated region D, which is plated to a predetermined thickness. Here, the plating area B is an area where the plating thickness may be thinner than that of the plating area D, that is, an area where plating is performed with a thickness greater than 0 and smaller than the upper limit of the predetermined range.

[0022] Next, a masking jig 61 used in the manufacturing method of the rod 11 will be described mainly with reference to FIGS. The masking jig 61 shown in Fig. 2 has a generally cylindrical shape with a lid. The masking jig 61 is mainly made of a conductive metal, specifically, a copper-based material. The masking jig 61 has a body 71, a lid 72, and a protrusion 73.

[0023] The body portion 71 is cylindrical, and its outer peripheral surface portion 71a on the radially outer side forms a cylindrical surface. The outer diameter of the body portion 71, i.e., the outer diameter of the outer peripheral surface portion 71a, is equal to the outer diameter of the base end shaft portion 31 of the rod 11 shown in FIG. 1, i.e., the outer diameter of the outer peripheral surface portion 31a. As shown in FIG. 2, the body portion 71 has an end surface portion 71b at one end in the axial direction. The end surface portion 71b is flat and extends perpendicular to the central axis of the outer peripheral surface portion 71a. The body portion 71 has a female thread (contact portion) (not shown) formed on its inner peripheral portion.

[0024] The body portion 71 has a hole 75 formed at an end opposite to the end face portion 71b in the axial direction, which penetrates the body portion 71 in the radial direction. A plurality of hole portions 75 (specifically, four locations) are formed in the body portion 71 at equal intervals in the circumferential direction of the body portion 71. These hole portions 75 are all the same shape, and are all aligned in the axial direction of the body portion 71. In the body portion 71, the region in the axial direction where the hole portion 75 is formed forms a partial opening portion 77. In addition, in the body portion 71, the region in the axial direction where the hole portion 75 is not formed forms a closed portion 78. The above-mentioned internal thread (not shown) is formed on the inner periphery of the closed portion 78.

[0025] The hole 75 has a flat surface 75a, a pair of side surfaces 75b, and a curved surface 75c. The flat surface 75a is located on the end surface 71b side of the hole 75 in the axial direction of the body 71. The flat surface 75a is flat and extends parallel to the end surface 71b. The pair of side surfaces 75b extend from both end edges of the flat surface 75a in the circumferential direction of the body 71 along the axial direction of the body 71 to the opposite side from the end surface 71b. The pair of side surfaces 75b are flat. The curved surface 75c connects the end edges of the pair of side surfaces 75b opposite the flat surface 75a in the axial direction of the body 71. The curved surface 75c curves so as to move away from the flat surface 75a in the axial direction of the body 71 as it moves toward the center in the circumferential direction of the body 71. The curved surface portion 75c has an end portion opposite the flat surface portion 75a in the axial direction of the body portion 71 aligned with an end portion of the lid portion 72 on the body portion 71 side in the axial direction.

[0026] 3, the maximum distance between the end surface portion 71b and the curved surface portion 75c in the axial direction of the trunk portion 71 is equal to the distance between the end surface portion 31b and the tip surface portion 42c in the axial direction of the rod 11. Moreover, the distance between the end surface portion 71b and the flat surface portion 75a in the axial direction of the trunk portion 71 is slightly longer than the distance between the end surface portion 31b and the end surface portion 41a in the axial direction of the rod 11. Moreover, the maximum distance between the flat surface portion 75a and the curved surface portion 75c in the axial direction of the trunk portion 71 is slightly shorter than the distance between the end surface portion 41a and the tip surface portion 42c in the axial direction of the rod 11.

[0027] The lid portion 72 shown in FIG. 2 is substantially disk-shaped and closes the end portion of the body portion 71 opposite to the end surface portion 71b in the axial direction. The protruding portion 73 is rod-shaped and protrudes from the center in the radial direction of the lid portion 72 to the opposite side from the body portion 71 in the axial direction of the lid portion 72. The protruding portion 73 is cylindrical and has an outer diameter smaller than the outer diameter of the lid portion 72.

[0028] The masking jig 61 comprises a substrate 81 made almost entirely of metal, specifically a copper-based material, and an insulating portion 82 covering a portion of the outer surface 81a of the substrate 81. The insulating portion 82 is formed by coating the outer surface 81a of the substrate 81 with an insulating material with good chromium acid resistance, specifically a fluorine-based material. The insulating portion 82 extends from the end surface 71b of the masking jig 61 to a predetermined position beyond the hole 75 in the axial direction of the masking jig 61 on the outer surface 61a. In other words, the insulating portion 82 extends from the entire portion of the outer surface 61a that is positioned on the body 71 to a portion of the lid 72 that is positioned on the body 71 side in the axial direction. The flat portion 75a of the hole 75, the pair of side surfaces 75b, and the curved surface 75c also form the insulating portion 82. The insulating portion 82 is generally cylindrical. An edge portion 82a on one axial end of the insulating portion 82 constitutes the end surface portion 71b. An edge portion 82b on the other axial end of the insulating portion 82 is circular and is disposed on a plane extending perpendicular to the central axis of the insulating portion 82. The edge portion 82b is disposed between the protrusion 73 and the hole 75 in the axial direction of the masking jig 61. The inner surface of the base material portion 81 also constitutes the insulating portion 82, except for the aforementioned female thread (not shown).

[0029] The masking jig 61 is configured such that the outer surface 81a of the base material 81 is exposed in a portion of its outer surface 61a excluding the insulating portion 82. That is, a portion of the outer surface of the lid portion 72 on the axial side opposite the body portion 71 and the outer surface of the protruding portion 73 form exposed surface portions 81b where the outer surface 81a of the base material 81 is exposed. In addition, the base material 81 is also exposed at the above-mentioned female thread (not shown) of the masking jig 61.

[0030] As shown in FIG. 4 , the masking jig 61 covers the tip shank 32 of the first shank 21 to mask the male thread 45 of the threaded shank 41. The female thread (not shown) of the masking jig 61 is threaded onto the male thread 45 of the rod 11. At this time, the masking jig 61 is threaded until the end surface 71b abuts on the end surface 31b of the rod 11 in surface contact. In this state, the end surface 71b of the masking jig 61, which is made of the insulating portion 82, is tightly and completely in contact with the end surface 31b of the rod 11. In this state, the lid portion 72 of the masking jig 61 is tightly and completely in contact with the tip surface 42c of the rod 11. In this state, the female thread (not shown) completely covers the male thread 45. In this state, the outer peripheral surface 71a formed by the insulating portion 82 of the trunk portion 71 is positioned on the same cylindrical surface as the outer peripheral surface 31a of the base-end shaft portion 31 of the rod 11. In this state, the flat surface 75a of the hole 75 is positioned slightly opposite the end surface 31b of the end surface 41a in the axial direction of the rod 11 and the masking jig 61. In this state, the curved surface 75c of the hole 75, at the end opposite the flat surface 75a in the axial direction of the rod 11 and the masking jig 61, is aligned with the tip surface 42c of the rod 11. Therefore, in this state, the hole 75 overlaps with the outer peripheral surfaces 42a, 42b of the tip end portion 42 of the rod 11 in the axial direction of the rod 11 and the masking jig 61. Therefore, the outer peripheral surface portions 42a, 42b of the tip end portion 42 of the rod 11 are exposed radially outward from the masking jig 61 through the hole portion 75.

[0031] In this state, the masking jig 61 has the aforementioned female thread (not shown) of the base portion 81 in contact with the male thread 45 of the distal shaft portion 32 of the rod 11. Also, in this state, the masking jig 61 has an outer surface 81a on the axial side of the base portion 81 opposite the base-end shaft portion 31, which is exposed to form an exposed surface portion 81b. Also, in this state, the insulating portion 82 covers the base portion 81 and the distal shaft portion 32 of the rod 11. At this time, the insulating portion 82 completely covers the entire circumference of the male thread 45 of the distal shaft portion 32 over its entire axial length. Also, in this state, the insulating portion 82 and the base portion 81 have a hole 75 at a position radially opposite the most distal end portion 42 of the distal shaft portion 32 of the rod 11, with the axial positions of the rod 11 and the masking jig 61 overlapping.

[0032] Next, the auxiliary cathode 101 and the rectifying member 102 used in the manufacturing method of the rod 11 will be described mainly with reference to FIG. The auxiliary cathode 101 is made of metal, specifically titanium. The auxiliary cathode 101 is cylindrical with a bottom, and the second shaft portion 22 of the rod 11 is inserted from its opening. The auxiliary cathode 101 is attached to the rod 11 by screwing onto the male thread 55 of the second shaft portion 22 of the rod 11. In this state, the end surface 101a of the auxiliary cathode 101 on the opening side is in close contact with the second end surface 20c of the rod 11 over its entire surface without any gaps. In addition, in this state, the outer circumferential surface 101b of the auxiliary cathode 101, which is a cylindrical surface, is arranged on the same cylindrical surface as the outer circumferential surface 20a of the main shaft portion 20 of the rod 11.

[0033] The flow rectifying member 102 is made of resin, specifically PTFE (polytetrafluoroethylene resin). The flow rectifying member 102 is joined to the auxiliary cathode 101 with its end surface 102a abutting against an end surface 101c opposite to the end surface 101a of the auxiliary cathode 101 in the axial direction. When joined to the auxiliary cathode 101, the flow rectifying member 102 has a hemispherical tip surface 102b opposite to the auxiliary cathode 101 in the axial direction. When joined to the auxiliary cathode 101, the cylindrical outer peripheral surface 102c of the flow rectifying member 102 is arranged on the same cylindrical surface as the outer peripheral surface 101b of the auxiliary cathode 101.

[0034] Next, a description will be given of a manufacturing method of the rod 11 according to the embodiment and a manufacturing apparatus 111. In the manufacturing method of the rod 11 according to the embodiment, plating is applied to the rod 11. Specifically, in the manufacturing method of the rod 11 according to the embodiment, chrome plating is applied to the surface of the steel rod 11.

[0035] The manufacturing apparatus 111 of the embodiment has an anode 121. The anode 121 is cylindrical and has a bottom, a cylindrical body 122, a disk-shaped bottom 123 closing one axial end of the body 122, and an opening 124 at the other axial end of the body 122. An opening end surface 124a of the opening 124 opposite the bottom 123 in the axial direction of the anode 121 is flat and extends perpendicular to the central axis of the body 122. The anode 121 has a vertical central axis, and the bottom 123 is located at its lower end. A liquid inlet 125 is provided in the bottom 123. The liquid inlet 125 opens upward and into the anode 121. The liquid inlet 125 is located at the center of the bottom 123, i.e., on the central axis of the anode 121.

[0036] Here, in the manufacturing method of rod 11 using manufacturing apparatus 111, auxiliary cathode 101 to which rectifying member 102 is fixed and masking jig 61 are attached to rod 11 as described above to form mounting body 141. Therefore, in this manufacturing method, tip shaft portion 32 of rod 11 is covered with masking jig 61.

[0037] The manufacturing apparatus 111 includes a power supply clamp 131 . In the manufacturing method of the rod 11, the power supply clamp 131 clamps the protruding portion 73 of the masking jig 61 of the mounting body 141. Then, in this manufacturing method, the power supply clamp 131 suspends the clamped mounting body 141 with the masking jig 61 on the upper side and the rectifying member 102 on the lower side, and inserts it into the anode 121 through the opening 124. Then, in this manufacturing method, the power supply clamp 131 aligns the mounting body 141 vertically at the radial center position of the trunk portion 122. That is, the power supply clamp 131 positions the mounting body 141 coaxially with the trunk portion 122. At this time, the power supply clamp 131 positions the edge portion 82b of the insulating portion 82 of the masking jig 61 a predetermined amount above the open end surface 124a of the anode 121. At this time, the power supply clamp 131 positions the entire hole 75 of the masking jig 61 below the opening end surface 124a.

[0038] In this state, rod 11 of attachment body 141 is arranged in the following order from the bottom: threaded shank 52 of second shank 22, base end shank 51 of second shank 22, main shank 20, base end shank 31 of first shank 21, threaded shank 41 of tip shank 32 of first shank 21, and most distal end 42 of tip shank 32 of first shank 21. Therefore, of main shank 20 and first shank 21, which has a smaller diameter than main shank 20, main shank 20 is located on the lower side, and first shank 21 is located on the upper side.

[0039] In the manufacturing method of rod 11, plating solution F is injected into anode 121. Then, a pump (not shown) discharges plating solution F from liquid inlet 125 into anode 121. This causes the plating solution F in anode 121 to flow vertically from bottom to top between trunk 122 and mounting body 141, as indicated by the two-dot chain arrow in FIG. 5 . Therefore, in this manufacturing method, plating solution F flows from the main shaft 20 side of rod 11 to the first shaft 21 side, which has a smaller diameter than main shaft 20. At the same time, excess plating solution F in anode 121 overflows from opening 124. Note that the height of mounting body 141 is set so that the liquid level of plating solution F is below edge 82b of insulating portion 82 of masking jig 61 and above hole 75.

[0040] In this manufacturing method, while this flow of plating solution F is generated between trunk portion 122 and mounting body 141, power is supplied from power supply clamp 131 to mounting body 141 to perform high-speed plating on rod 11. As a result, plating having a thickness within the predetermined range is electrodeposited on metal rod 11 in plating region D shown in FIG. 1 that is immersed in plating solution F and is not covered at all by masking jig 61 or auxiliary cathode 101, i.e., outer peripheral surface 20a and first end surface 20b of main shaft portion 20 and outer peripheral surface 31a of base-end shaft portion 31 shown in FIG. 5. Furthermore, plating having a thickness greater than 0 and less than the upper limit of the predetermined range is electrodeposited on plating region B and plating region C shown in FIG. 1 that are immersed in plating solution F and are covered by partial opening 77 of masking jig 61 but are exposed through hole 75, i.e., outer peripheral surface portions 42a, 42b of tip end portion 42 shown in FIG. 5.

[0041] In contrast, plating is not electrodeposited on male threads 45 of threaded shank 41 shown in FIG. 4 , which are threadedly engaged with and covered by the female thread (not shown) of blocking portion 78 of masking jig 61, and on end surface portion 31b of base-end shank 31, which is covered by blocking portion 78, i.e., non-plating region A2 shown in FIG. 1 . Also, as shown in FIG. 5 , plating is not electrodeposited on non-plating region A1 shown in FIG. 1 , which is immersed in plating solution F but is covered by auxiliary cathode 101, i.e., second end surface portion 20c of main shaft 20, and outer peripheral surface portion 51a, male threads 55, and tip surface portion 52a of second shank 22, shown in FIG. 5 . In addition, plating is not electrodeposited on through-hole 12, the lower end of which is blocked by auxiliary cathode 101 and the upper end of which is blocked by lid portion 72 of masking jig 61. The rectifying member 102 attached to the auxiliary cathode 101 rectifies the plating solution F discharged from the opposing solution inlet 125 to suppress current concentration on the rod 11 .

[0042] In the embodiment, the rod 11 and the anode 121 are arranged to extend in the vertical direction, but the arrangement is not limited thereto and they may be arranged to extend in any direction. For example, the rod 11 and the anode 121 may be arranged to extend in the horizontal direction. In this case, too, the plating solution F is caused to flow from the rectifying member 102 side to the masking jig 61 side, as in the above.

[0043] The above-mentioned Patent Document 1 discloses a technology for controlling the flow of current in a plating bath by providing an insulating member and a hole through which the insulating member passes, and arranging the portion requiring plating and the hole in the insulating member so as to face each other. However, when plating a rod, it is desired to suppress a decrease in productivity.

[0044] When plating rod 11 of the embodiment, we considered a method opposite to the embodiment, in which second shank portion 22 is clamped with power supply clamp 131 to suspend rod 11, and plating solution F is poured from first shank portion 21 toward main shank portion 20. In this case, we considered preventing plating from adhering to non-plating area A1 by not immersing it in plating solution F. We also considered creating a non-plating area by blocking through-hole 12 with a resin or metal shielding member that abuts tip surface portion 42c. We also considered covering threaded shank portion 41 of first shank portion 21 with a titanium auxiliary cathode to form non-plating area A2. We considered covering threaded shank portion 41 with a resin insulating material, but this could result in abnormal plating deposition on end surface portion 31b, so we decided to use titanium. By doing this, we considered forming non-plating areas A1 and A2 and plating areas B, C, and D.

[0045] However, if plating is performed in this manner, current concentration can cause abnormal deposition of the plating on first end surface portion 20b of main shaft portion 20, potentially resulting in a loss of gloss and other degradation of plating quality. This possibility is particularly high when high-speed plating is performed. On the other hand, because outer peripheral surface portion 31a of base-end shank portion 31 of first shank portion 21 and outer peripheral surface portion 20a of main shaft portion 20 must be plated, it is difficult to cover first end surface portion 20b between them with a masking jig. For these reasons, plating must be performed at a low current density, posing a problem in terms of productivity.

[0046] In contrast, the manufacturing method of rod 11 of the embodiment uses masking jig 61 including: metal substrate portion 81 having a smaller diameter than main shaft portion 20 and the aforementioned female thread (not shown) that contacts male thread 45 of tip shank portion 32 of first shank portion 21 located at the end; and insulating portion 82 covering substrate portion 81 and first shank portion 21 and having hole 75 located opposite tip shank portion 32. Plating solution F is then flowed from the main shaft portion 20 side to the first shank portion 21 side, bringing rod 11 into contact with plating solution F. By flowing plating solution from the main shaft portion 20 side to the first shank portion 21 side, which has a smaller diameter, abnormal deposition of plating on first end surface portion 20b of main shaft portion 20, such as loss of gloss, can be suppressed. Therefore, the manufacturing method of rod 11 of the embodiment makes it possible to perform plating of rod 11 while maintaining quality without performing plating treatment at a low current density, thereby suppressing a decrease in productivity. Moreover, because masking jig 61 has insulating portion 82 that covers base portion 81 and first shank portion 21, plating can be prevented from being applied to base portion 81. In addition, insulating portion 82 has hole 75 at a position facing forwardmost portion 42 of tip shank portion 32, so plating can also be applied to forwardmost portion 42. Because insulating portion 82 has hole 75 at a position facing forwardmost portion 42, current concentration at forwardmost portion 42 can be prevented, and abnormal deposition of plating on forwardmost portion 42 can be prevented.

[0047] Furthermore, since the base material 81 of the masking jig 61 is made of a copper-based material with high electrical conductivity, the base material 81 of the masking jig 61 can be used as a power supply portion, enabling good high-speed plating. [Explanation of symbols]

[0048] 11...Rod, 20...Main shaft portion (large diameter portion), 21...First shaft portion (small diameter portion), 32...Tip shaft portion (end portion), 61...Masking jig, 75...Hole portion, 81...Base material portion, 82...Insulating portion, F...Plating solution.

Claims

1. a large diameter portion and a small diameter portion that is smaller in diameter than the large diameter portion and is located at an end, The small diameter portion is a base end shaft portion which is a plated region; a tip shaft portion at an end of the small diameter portion and including a non-plated region, The tip shaft portion is a screw shank portion which is a non-plated region; a tip end portion including a plating region; a masking jig including a metal substrate having a contact portion on an inner periphery thereof that contacts the screw shank portion of the small diameter portion, a hole portion at a position opposite the most distal end portion, and an insulating portion that covers a range from an end face portion of the substrate to a predetermined position beyond the hole portion in the axial direction, which is a part of the substrate; A method for manufacturing a rod, in which a plating solution is brought into contact with the rod by flowing the plating solution from the large diameter portion side to the small diameter portion side.

2. The method for manufacturing a rod according to claim 1, wherein the substrate portion is made of a copper-based material.

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