JP7784905B2 - Rod manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a rod.

There is a technology in which an insulating member and a hole through which the insulating member passes are placed in the current flow in a plating bath, and the current flow is controlled by arranging the part requiring plating facing the hole in the insulating member (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2019-214765

However, when plating rods, it is necessary to suppress declines in productivity.

Therefore, the present invention aims to provide a rod manufacturing method that can suppress declines in productivity.

To achieve the above objective, the first aspect of the present invention is a method for manufacturing a rod that plating is performed on a rod having a large diameter portion and a small diameter portion that is smaller than the large diameter portion and located at the end. The method uses a masking jig that includes a metal substrate having a contact portion that contacts the end of the small diameter portion, and an insulating portion that covers the substrate and the small diameter portion and has a hole in a position opposite the end. The plating solution is brought into contact with the rod by flowing it from the large diameter portion side to the small diameter portion side.

This invention makes it possible to prevent declines in productivity.

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. FIG. 2 is a front view showing a masking jig used in the rod manufacturing method according to the embodiment of the present invention. 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. 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. 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.

Embodiments of the present invention are described below with reference to the drawings.

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 passes through the rod 11 in the axial direction.

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. 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. Both the first end surface portion 20b and the second end surface portion 20c are flat surfaces that extend perpendicular to the central axis of the outer peripheral surface portion 20a.

The first shank 21 extends from the first end surface 20b of the main shaft 20 along the axial direction of the main shaft 20. The first shank 21 is located at one axial end of the rod 11. The first shank 21 is generally cylindrical, and its outer diameter is smaller than the outer diameter of the main shaft 20 over its entire axial length. The first shank 21 has a base end shank 31 and a tip end shank 32 (end).

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

The tip shaft portion 32 is located at the end of the first shaft portion 21 opposite the main shaft portion 20 in the axial direction, and has a threaded shaft portion 41 and a tip end portion 42.

The threaded shank 41 is located on the axial side of the distal shank 32 toward the base shank 31, and extends from the end face 31b of the base shank 31 along the axial direction of the base shank 31. The threaded shank 41 is generally cylindrical, and its outer diameter is smaller than that of the base shank 31 along 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 shank 31 in the axial direction. The end face 41a is flat and extends perpendicular to the central axis of the male thread 45.

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

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

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

The threaded shank 52 is located on the axial opposite side of the second shank 22 from the main shank 20, and forms the other end opposite the axially most distal end 42 of the rod 11. The threaded shank 52 is generally cylindrical, with a male thread 55 formed on its outer periphery. The threaded shank 52 has a tip surface 52a at the end opposite the axially distal end shank 51. The tip 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 tip surface 52a forms the tip surface opposite the axially distal end surface 42c of the rod 11. One end of a through hole 12 opens in the radial center of the tip surface 42c, and the other end of the through hole 12 opens in the radial center of the tip surface 52a.

The rod 11 constitutes a cylinder device. A cylinder device is, for example, a shock absorber used in the suspension systems of vehicles such as automobiles and railway cars. 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 the 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 securing 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 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.

In the rod 11, the second end surface 20c of the main shaft portion 20, the outer peripheral surface 51a, male thread 55, and tip surface 52a of the second shaft portion 22, all of which are on the side attached to the vehicle body, are non-plated areas A1. In the rod 11, the male thread 45 of the threaded shank portion 41 is non-plated area A2. In the rod 11, the outer peripheral surface 42a of the most distal portion 42 is plated area B, which is plated. In the rod 11, the outer peripheral surface 42b of the most distal portion 42 is plated area C, which may or may not be plated. In the rod 11, the outer peripheral surface 20a and first end surface 20b of the main shaft portion 20, and the outer peripheral surface 31a of the base end shaft portion 31 are plated area D, which is plated to a predetermined thickness. Here, plating area B is an area where the plating thickness can be thinner than plating area D, i.e., an area where plating is applied to a thickness greater than 0 and less than the upper limit of the specified range.

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 made mainly of a conductive metal, specifically, a copper-based material. The masking jig 61 has a body 71, a lid 72, and a protrusion 73.

The body 71 is cylindrical, with its radially outer outer peripheral surface 71a forming a cylindrical surface. The outer diameter of the body 71, i.e., the outer diameter of the outer peripheral surface 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 31a. As shown in FIG. 2, the body 71 has an end surface 71b at one axial end. The end surface 71b is flat and extends perpendicular to the central axis of the outer peripheral surface 71a. The body 71 has a female thread (contact portion) (not shown) formed on its inner peripheral portion.

A hole 75 is formed in the barrel 71 at the end opposite the end surface 71b in the axial direction, penetrating the barrel 71 in the radial direction. A plurality of holes 75 (specifically, four holes) are formed in the barrel 71 at equal intervals around the circumference of the barrel 71. All of these holes 75 have the same shape, and are all aligned in the axial direction of the barrel 71. The area of the barrel 71 where the hole 75 is formed defines a partial opening 77. The area of the barrel 71 where no hole 75 is formed defines a closed section 78. The aforementioned internal thread (not shown) is formed on the inner periphery of the closed section 78.

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

As shown in FIG. 3, the maximum distance between the end surface 71b and the curved surface 75c in the axial direction of the body 71 is equal to the distance between the end surface 31b and the tip surface 42c in the axial direction of the rod 11. Furthermore, the distance between the end surface 71b and the flat surface 75a in the axial direction of the body 71 is slightly longer than the distance between the end surface 31b and the end surface 41a in the axial direction of the rod 11. Furthermore, the maximum distance between the flat surface 75a and the curved surface 75c in the axial direction of the body 71 is slightly shorter than the distance between the end surface 41a and the tip surface 42c in the axial direction of the rod 11.

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 of the lid portion 72 in the radial direction toward the opposite side of 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.

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

The masking jig 61 is configured so that the outer surface 61a of the base material 81 is exposed, excluding the insulating portion 82. In other words, part of the outer surface of the lid portion 72 on the axial side opposite the body portion 71 and the outer surface of the protrusion 73 form exposed surface portions 81b where the outer surface 81a of the base material 81 is exposed. Furthermore, the base material 81 is also exposed at the aforementioned female thread (not shown) of the masking jig 61.

As shown in FIG. 4, the masking jig 61 covers the tip shaft portion 32 of the first shaft portion 21 and masks the male thread 45 of the threaded shaft portion 41. The masking jig 61 has its female thread (not shown) threaded onto the male thread 45 of the rod 11. The masking jig 61 is threaded until the end surface portion 71b abuts the end surface portion 31b of the rod 11 in surface contact. In this state, the end surface portion 71b of the masking jig 61, which is made of the insulating portion 82, is tightly and completely in contact with the end surface portion 31b of the rod 11. In this state, the cover portion 72 of the masking jig 61 is tightly and completely in contact with the tip surface portion 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 body 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 42 of the rod 11 in the axial direction of the rod 11 and the masking jig 61. Therefore, the outer peripheral surfaces 42a and 42b of the most distal end 42 of the rod 11 are exposed radially outward from the masking jig 61 through the hole 75.

In this state, the masking jig 61 has the aforementioned female thread (not shown) of the base material 81 in contact with the male thread 45 of the distal shaft portion 32 of the rod 11. Also, in this state, the outer surface 81a of the masking jig 61 on the axial side opposite the base material 81 from the proximal shaft portion 31 is exposed, forming an exposed surface portion 81b. Also, in this state, the insulating portion 82 covers the base material 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 material 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.

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 the 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.

The flow straightening member 102 is made of resin, specifically PTFE (polytetrafluoroethylene resin). The flow straightening member 102 is joined to the auxiliary cathode 101 by abutting its end surface 102a against the end surface 101c of the auxiliary cathode 101 opposite the end surface 101a in the axial direction. When joined to the auxiliary cathode 101, the end surface 102b of the flow straightening member 102, which is on the axial side opposite the auxiliary cathode 101, is hemispherical. When joined to the auxiliary cathode 101, the cylindrical outer peripheral surface 102c of the flow straightening member 102 is positioned on the same cylindrical surface as the outer peripheral surface 101b of the auxiliary cathode 101.

Next, a method for manufacturing the rod 11 and a manufacturing device 111 according to the embodiment will be described. In the method for manufacturing the rod 11 according to the embodiment, plating is applied to the rod 11. Specifically, the method for manufacturing the rod 11 according to the embodiment involves chrome plating the surface of the steel rod 11.

The manufacturing apparatus 111 of this embodiment has an anode 121. The anode 121 is cylindrical and has a bottom, a cylindrical body 122, a disc-shaped bottom 123 closing one axial end of the body 122, and an opening 124 at the other axial end of the body 122. The 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 in the center of the bottom 123, i.e., on the central axis of the anode 121.

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

The manufacturing apparatus 111 has 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.

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

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

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

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

In this embodiment, the rod 11 and anode 121 are arranged to extend vertically, but this is not limiting and they may be arranged to extend in any direction. For example, the rod 11 and anode 121 may be arranged to extend horizontally. In this case, too, the plating solution F is caused to flow from the straightening member 102 side to the masking jig 61 side, as described above.

The aforementioned 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 positioning the portion requiring plating opposite the hole in the insulating member. However, when plating rods, there is a need to prevent a decline in productivity.

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

However, if plating is performed in this manner, current concentration can cause abnormal deposition of the plating on the first end surface 20b of the 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 plating is required on the outer peripheral surface 31a of the base-end shaft portion 31 of the first shaft portion 21 and the outer peripheral surface 20a of the main shaft portion 20, it is difficult to cover the first end surface 20b between them with a masking jig. For these reasons, plating must be performed at a low current density, posing challenges in terms of productivity.

In contrast, the manufacturing method for rod 11 of the embodiment uses a masking jig 61 including: a metal substrate 81 having a smaller diameter than the main shaft portion 20 and the aforementioned female threads (not shown) that contact the male threads 45 of the tip shank 32 of the first shank portion 21 located at the end; and an insulating portion 82 covering the substrate 81 and the first shank portion 21 and having a hole 75 located opposite the tip shank 32. Plating solution F is then flowed from the main shaft portion 20 side to the first shank portion 21 side, bringing the plating solution F into contact with the rod 11. By flowing the plating solution from the main shaft portion 20 side to the smaller-diameter first shank portion 21 side in this manner, abnormal plating deposition on the first end surface 20b of the main shaft portion 20, such as loss of gloss, can be prevented, thereby preventing deterioration in plating quality. Therefore, the manufacturing method for rod 11 of the embodiment enables high-quality plating to be applied to rod 11 without plating at a low current density, thereby preventing productivity losses. Furthermore, because the masking jig 61 has an insulating portion 82 that covers the base portion 81 and the first shank portion 21, plating on the base portion 81 is prevented. Additionally, because the insulating portion 82 has a hole 75 located opposite the most distal end portion 42 of the tip shank portion 32, plating can also be applied to the most distal end portion 42. Because the insulating portion 82 has a hole 75 located opposite the most distal end portion 42, current concentration on the most distal end portion 42 is prevented, and abnormal plating deposition on the most distal end portion 42 is prevented.

In addition, because 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, enabling excellent high-speed plating.

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 (2)

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,
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. The rod manufacturing method described in claim 1, wherein the substrate portion is made of a copper-based material.