Rod manufacturing method and cathode member

Abstract

The present invention provides a rod manufacturing method and a cathode component that can suppress a decrease in productivity. [Solution] A method for manufacturing a rod having a large diameter portion, a small diameter portion smaller than the large diameter portion, and a flange portion connecting the large diameter portion and the small diameter portion, wherein a cathode member 81 is attached to the rod and has an engagement hole 101 that engages with the small diameter portion, a contact portion 93 that extends outward from the engagement hole 101 in the radial direction and abuts against the flange portion, and a tapered tip portion 121 provided at the end opposite to the contact portion 93, the outer diameter of which becomes smaller on the side opposite to the contact portion 93, and a discharge hole 118 that can discharge the plating solution that has entered the engagement hole 101, and a plating solution is flowed toward the cathode member 81.

Description

[Technical Field]

[0001] The present invention relates to a rod manufacturing method and a cathode member. [Background Art]

[0002] There is a known technique of performing plating treatment by attaching a tapered-tip cathode member to a rod (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2021-155800 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] A cathode member is provided with an engagement hole for engaging a rod, but if a plating solution enters this engagement hole, there is a possibility that productivity will be reduced.

[0005] Accordingly, an object of the present invention is to provide a rod manufacturing method and a cathode member that can suppress a decrease in productivity. [Means for Solving the Problems]

[0006] In order to achieve the above object, a rod manufacturing method according to the present invention is a rod manufacturing method for plating the large-diameter portion of a rod including a large-diameter portion, a small-diameter portion having a smaller diameter than the large-diameter portion, and a flange portion connecting the large-diameter portion and the small-diameter portion, wherein the method is configured such that a cathode member is attached to the rod, and a plating solution is flowed toward the cathode member, the cathode member including: an engagement hole that engages with the small-diameter portion; an abutment portion that spreads outward from the engagement hole in a radial direction of the engagement hole and abuts against the flange portion; and a tapered tapered tip portion that is provided at an end opposite to the abutment portion, has an outer diameter that decreases toward the side opposite to the abutment portion, and has a discharge hole capable of discharging the plating solution that has entered the engagement hole.

[0007] The cathode member according to the present invention is a cathode member used when plating the large-diameter portion of a rod having a large-diameter portion, a small-diameter portion having a smaller diameter than the large-diameter portion, and a flange portion connecting the large-diameter portion and the small-diameter portion, and is configured to have an engagement hole that engages with the small-diameter portion, a contact portion that extends outward from the engagement hole in the radial direction and abuts against the flange portion, a tapered tip portion provided at the end opposite to the contact portion and having a tapered shape in which the outer diameter becomes smaller on the side opposite to the contact portion, and a discharge hole that can discharge the plating solution that has entered the engagement hole. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the decline in productivity. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing a cylinder device including a rod manufactured by a rod manufacturing method according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view showing a cathode member used in a rod manufacturing method according to one embodiment of the present invention. [Figure 3] This is an exploded cross-sectional view showing a cathode member used in a rod manufacturing method according to one embodiment of the present invention. [Figure 4] This is a cross-sectional view showing the state of a plating apparatus used in a rod manufacturing method according to one embodiment of the present invention, before the plating process. [Figure 5] This is a cross-sectional view showing the state of a plating apparatus used in a rod manufacturing method according to one embodiment of the present invention during the plating process. [Modes for carrying out the invention]

[0010] A method for manufacturing a rod and a cathode member according to one embodiment of the present invention will be described below with reference to the drawings.

[0011] First, the cylinder device 11 including the rod 10 manufactured by the manufacturing method of this embodiment will be described with reference to Figure 1. The cylinder device 11 shown in Figure 1 is a shock absorber used in the suspension system of vehicles such as automobiles and railway vehicles, and more specifically, a shock absorber used in the suspension system of an automobile. The cylinder device 11 is a twin-tube type shock absorber comprising a cylinder 17 having a cylindrical inner cylinder 15 and a bottomed cylindrical outer cylinder 16 which is larger in diameter than the inner cylinder 15 and is provided on the outer circumference of the inner cylinder 15, covering the outer circumference of the inner cylinder 15. A reservoir chamber 18 is located between the outer cylinder 16 and the inner cylinder 15.

[0012] The outer cylinder 16 is a one-piece molded product made of a metal component, and has a cylindrical body portion 21, a bottom portion 22 that closes one end of the body portion 21 in the axial direction, and an opening 23 on the opposite side of the body portion 21 from the bottom portion 22. The inner cylinder 15 is a one-piece molded product made of a metal component, and is cylindrical in shape.

[0013] The cylinder device 11 includes an annular valve body 25 provided at one axial end of the inner cylinder 15, and an annular rod guide 26 provided at the other axial ends of the inner cylinder 15 and the outer cylinder 16. The valve body 25 constitutes the body valve 30, and its outer circumference has a small diameter portion and a larger diameter portion. The rod guide 26 also has a small diameter portion and a larger diameter portion on its outer circumference.

[0014] The inner cylinder 15 has one axial end fitted to the small-diameter portion of the outer circumference of the valve body 25, and engages with the bottom 22 of the outer cylinder 16 via the valve body 25. The other axial end of the inner cylinder 15 is fitted to the small-diameter portion of the outer circumference of the rod guide 26, and engages with the body 21 of the outer cylinder 16 via the rod guide 26. In this state, the inner cylinder 15 is positioned radially relative to the outer cylinder 16. Here, the space between the valve body 25 and the bottom 22 communicates with the space between the inner cylinder 15 and the outer cylinder 16 via a passage groove 35 formed in the valve body 25, and, similar to the space between the inner cylinder 15 and the outer cylinder 16, constitutes a reservoir chamber 18.

[0015] The cylinder device 11 has an annular sealing member 41 on the side opposite to the bottom 22 of the rod guide 26. This sealing member 41 is fitted to the inner circumference of the body 21, similar to the rod guide 26. At the end of the body 21 opposite to the bottom 22, a locking portion 43 is formed by plastically deforming the body 21 radially inward through crimping, such as curling. The sealing member 41 is sandwiched between this locking portion 43 and the rod guide 26. The sealing member 41 closes the opening 23 of the outer cylinder 16, and is specifically an oil seal. The sealing member 41 may also be made of a sealing washer.

[0016] The cylinder device 11 has a piston 45 provided inside a cylinder 17. The piston 45 is slidably fitted into the inner cylinder 15. The piston 45 divides the inside of the inner cylinder 15 into two chambers: a first chamber 48 and a second chamber 49. The first chamber 48 is provided between the piston 45 and the rod guide 26 inside the inner cylinder 15, and the second chamber 49 is provided between the piston 45 and the valve body 25 inside the inner cylinder 15. The second chamber 49 is defined as a reservoir chamber 18 by the valve body 25. The first chamber 48 and the second chamber 49 are filled with oil liquid L as a working fluid, and the reservoir chamber 18 is filled with gas G as a working fluid and oil liquid L.

[0017] The cylinder device 11 has a rod 10, one end of which is connected to a piston 45, and the other end of which extends outward from the outer cylinder 16 of the cylinder 17 through an opening 23. The piston 45 is connected to the rod 10 by a nut 51.

[0018] The rod 10 is made of metal and has a cylindrical large-diameter portion 55, a cylindrical small-diameter portion 58 whose outer diameter is smaller than the outer diameter of the large-diameter portion 55, an annular flange portion 57 connecting the large-diameter portion 55 and the small-diameter portion 58, and a mounting shaft portion 56 provided on the opposite side of the large-diameter portion 55 from the small-diameter portion 58. The large-diameter portion 55, the small-diameter portion 58, and the mounting shaft portion 56 are arranged coaxially with their central axes aligned.

[0019] The large diameter portion 55 has an outer peripheral surface 55a formed of a cylindrical surface. The flange portion 57 has an outer surface 57a facing toward the small diameter portion 58 side formed of an annular flat surface. The outer peripheral portion of the small diameter portion 58 is formed as an external thread 58a. The mounting shaft portion 56 has a small diameter shaft portion 61 whose outer peripheral surface 61a is formed of a cylindrical surface on the large diameter portion 55 side, and has a small diameter threaded shaft portion 62 whose outer peripheral portion is formed as an external thread 62a on the side opposite to the large diameter portion 55. The outer peripheral surface 55a, the external thread 58a, the outer peripheral surface 61a, and the external thread 62a are arranged coaxially with their central axes aligned, and the outer surface 57a is a flat surface extending perpendicularly to the central axis. The piston 45 is fitted onto the small diameter shaft portion 61. The nut 51 is screwed onto the external thread 62a of the small diameter threaded shaft portion 62.

[0020] The rod 10 extends from the inner cylinder 15 and the outer cylinder 16 to the outside through the rod guide 26 and the seal member 41 at the large diameter portion 55. Accordingly, one end side of the rod 10 is arranged inside the outer cylinder 16 and the inner cylinder 15, and the other end side is arranged outside the outer cylinder 16 and the inner cylinder 15. The large diameter portion 55 of the rod 10 is in sliding contact with the rod guide 26 at the outer peripheral surface 55a, and the rod 10 is guided by the rod guide 26 and moves axially integrally with the piston 45 relative to the inner cylinder 15 and the outer cylinder 16. The large diameter portion 55 of the rod 10 is in sliding contact with the seal member 41 at the outer peripheral surface 55a, and the seal member 41 closes the gap between the outer cylinder 16 and the rod 10, and restricts the leakage of the working liquid in the inner cylinder 15, and the working gas and working liquid in the reservoir chamber 18 to the outside.

[0021] The piston 45 is formed with a passage 65 and a passage 66 penetrating in the axial direction. The passages 65 and 66 are capable of communicating the first chamber 48 and the second chamber 49. The cylinder device 11 has an annular disc valve 67 capable of closing the passage 65 by abutting against the piston 45 on the side opposite to the bottom portion 22 in the axial direction of the piston 45. Further, the cylinder device 11 has an annular disc valve 68 capable of closing the passage 66 by abutting against the piston 45 on the bottom portion 22 side in the axial direction of the piston 45. The disc valves 67 and 68 are connected to the rod 10 together with the piston 45.

[0022] When the rod 10 moves on the compression stroke side that increases the amount of entry into the inner cylinder 15 and the outer cylinder 16, the piston 45 moves in the direction of narrowing the second chamber 49, and the pressure in the second chamber 49 becomes higher than the pressure in the first chamber 48 by a predetermined value or more, the disc valve 67 opens the passage 65 to allow the oil liquid L in the second chamber 49 to flow into the first chamber 48, and generates a damping force at this time. When the rod 10 moves on the extension stroke side that increases the amount of protrusion from the inner cylinder 15 and the outer cylinder 16, the piston 45 moves in the direction of narrowing the first chamber 48, and the pressure in the first chamber 48 becomes higher than the pressure in the second chamber 49 by a predetermined value or more, the disc valve 68 opens the passage 66 to allow the oil liquid L in the first chamber 48 to flow into the second chamber 49, and generates a damping force at this time.

[0023] At least one of the piston 45 and the disc valve 67 is formed with an unillustrated fixed orifice that allows communication between the first chamber 48 and the second chamber 49 via the passage 65 even when the disc valve 67 blocks the passage 65 most tightly. Also, at least one of the piston 45 and the disc valve 68 is formed with an unillustrated fixed orifice that allows communication between the first chamber 48 and the second chamber 49 via the passage 66 even when the disc valve 68 blocks the passage 66 most tightly.

[0024] The valve body 25 is formed with a liquid passage 71 and a liquid passage 71 penetrating in the axial direction. The liquid passages 71 and 72 enable communication between the second chamber 49 and the reservoir chamber 18. The body valve 30 has an annular disc valve 75 on the bottom 22 side of the valve body 25 in the axial direction, the disc valve 75 being capable of blocking the liquid passage 71 by abutting against the valve body 25. The body valve 30 also has an annular disc valve 76 on the side opposite to the bottom 22 of the valve body 25 in the axial direction, the disc valve 76 being capable of blocking the liquid passage 72 by abutting against the valve body 25. The body valve 30 has a pin 78, and the disc valves 75 and 76 are fixed to the valve body 25 by the pin 78. The body valve 30, which is composed of the valve body 25, the disc valves 75, 76, the pin 78 and other components, divides the cylinder 17 into two chambers: the second chamber 49 and the reservoir chamber 18.

[0025] When the rod 10 moves in the compression direction and the piston 45 moves in a direction that narrows the second chamber 49, causing the pressure in the second chamber 49 to become higher than a predetermined value than the pressure in the reservoir chamber 18, the disc valve 75 opens the fluid passage 71, generating a damping force. When the rod 10 moves in the extension direction and the piston 45 moves toward the first chamber 48, causing the pressure in the second chamber 49 to drop below the pressure in the reservoir chamber 18, the disc valve 76 opens the fluid passage 72. The disc valve 76 is a suction valve that allows oil L to flow from the reservoir chamber 18 into the second chamber 49 without generating a damping force.

[0026] The cylinder device 11, for example, has a rod 10 connected to the vehicle body at a small diameter portion 58, and a cylinder 17 connected to the vehicle wheel, generating a damping force against the movement of the wheel relative to the vehicle body.

[0027] Next, the manufacturing method of the rod 10 in this embodiment will be described. In the manufacturing method of the rod 10 in this embodiment, the large-diameter portion 55 of the rod 10 is plated. Specifically, the outer circumferential surface 55a of the large-diameter portion 55 of the steel rod 10 is plated with chromium.

[0028] The rod 10 has a large diameter portion 55 that slides against the rod guide 26 and the sealing member 41 on its outer circumferential surface 55a. The rod 10 also has a piston 45 fitted onto a small diameter shaft portion 61 of the mounting shaft portion 56, and a nut 51 screwed onto a small diameter screw shaft portion 62. The rod 10 is the object to be plated, and the plating is electrodeposited onto the large diameter portion 55 that slides against the rod guide 26 and the sealing member 41, or that is exposed to the outside of the sealing member 41. Specifically, the plating is electrodeposited onto the outer circumferential surface 55a of the large diameter portion 55. On the other hand, measures are needed to suppress electrodeposition in areas where electrodeposition is not desired.

[0029] In the manufacturing method of the rod 10 of this embodiment, the cathode member 81 shown in Figure 2 is used. The manufacturing method of the rod 10 in this embodiment involves covering the small-diameter portion 58, to which plating is not to be electrodeposited, with the cathode member 81 shown in Figure 2, while electrodepositing the plating onto the outer circumferential surface 55a of the large-diameter portion 55 of the rod 10.

[0030] The cathode member 81 is composed of two parts connected together: a cathode member body 82 made of a metal such as titanium, and a tip member 83 made of a synthetic resin such as PTFE (polytetrafluoroethylene). The cathode member body 82 and the tip member 83 are detachable.

[0031] As shown in Figure 3, the cathode member body 82 is made of a single, seamless piece and has a cylindrical main body 91 and a protruding shaft portion 92 that protrudes from one end of the main body 91 in the axial direction.

[0032] The main body 91 has a cylindrical outer surface 91a. The outer diameter of the main body 91, i.e., the diameter of the outer surface 91a, is the same as the outer diameter of the large diameter portion 55 of the rod 10 shown in Figure 1, i.e., the diameter of the outer surface 55a. In the main body 91 shown in Figure 2, the end opposite to the axially protruding shaft portion 92 is a contact portion 93. The end face 93a of the contact portion 93, opposite to the axially protruding shaft portion 92, is a flat surface that extends perpendicularly to the central axis of the outer surface 91a of the main body 91. The end of the main body 91 on the side of the axially protruding shaft portion 92 is a joint portion 94. The end face 94a of the joint portion 94, on the side of the axially protruding shaft portion 92, is a flat surface that extends perpendicularly to the central axis of the outer surface 91a of the main body 91. The end face 93a of the contact portion 93 and the end face 94a of the joint portion 94 are circular with the central axis of the outer surface 91a.

[0033] The main body 91 has an engagement hole 101 formed in a shape that is recessed from the end face 93a of the contact portion 93 toward the joint portion 94. The engagement hole 101 has a mouth hole portion 102 on the end face 93a side, whose inner circumferential surface 102a is a cylindrical surface, and a screw hole portion 103 on the opposite side from the end face 93a, whose inner circumferential surface is a female thread 103a. The inner circumferential surface 102a of the mouth hole portion 102 and the female thread 103a of the screw hole portion 103 are arranged coaxially with the outer circumferential surface 91a and their central axis. The contact portion 93 extends radially outward from the engagement hole 101.

[0034] The protruding shaft portion 92 has a cylindrical base shaft portion 89 that protrudes from one axial end of the main body portion 91, and a tip shaft portion 90 provided on the opposite side of the base shaft portion 89 from the main body portion 91. The main body portion 91 and the base shaft portion 89 and tip shaft portion 90 of the protruding shaft portion 92 are arranged coaxially with their central axes aligned.

[0035] The base shaft portion 89 of the protruding shaft portion 92 has a cylindrical outer surface 89a. The outer diameter of the base shaft portion 89, i.e., the diameter of the outer surface 89a, is smaller than the outer diameter of the main body portion 91, i.e., the diameter of the outer surface 91a. The outer surface 89a of the base shaft portion 89 and the outer surface 91a of the main body portion 91 are arranged coaxially with their central axes aligned.

[0036] The tip shaft portion 90 of the protruding shaft portion 92 has a male thread 90a on its outer circumference. The outer diameter of the tip shaft portion 90, i.e., the outer diameter of the male thread 90a, is smaller than the outer diameter of the main body portion 91, i.e., the diameter of the outer surface 91a, and larger than the outer diameter of the base shaft portion 89, i.e., the diameter of the outer surface 89a. The end face 90b of the tip shaft portion 90, opposite to the base shaft portion 89, is a flat surface that extends perpendicularly to the central axis of the tip shaft portion 90. This end face 90b is the end face of the protruding shaft portion 92 opposite to the main body portion 91. The outer surface 91a of the main body portion 91, the outer surface 89a of the base shaft portion 89, and the male thread 90a of the tip shaft portion 90 are arranged coaxially with their central axes aligned.

[0037] The cathode member body 82 has a communication hole 105 that extends from the bottom surface 101a opposite to the end surface 93a of the engagement hole 101 to the end surface 90b of the tip shaft portion 90. One end of the communication hole 105 opens to the bottom surface 101a of the engagement hole 101, and the other end opens to the end surface 90b of the tip shaft portion 90. Thus, the communication hole 105 is formed at the end of the main body 91 on the side of the protruding shaft portion 92, and at the base shaft portion 89 and tip shaft portion 90 of the protruding shaft portion 92. The inner circumferential surface 105a of the communication hole 105 is cylindrical, and it is arranged coaxially with the inner circumferential surface 102a of the mouth hole portion 102 of the engagement hole 101 and the female thread 103a of the screw hole portion 103, with their central axes aligned. In other words, the communication hole 105 is formed coaxially with the engagement hole 101, with their central axes aligned. The diameter of the inner circumferential surface 105a, which is the inner diameter of the communication hole 105, is smaller than the diameter of the inner circumferential surface 102a, which is the inner diameter of the opening hole portion 102 of the engagement hole 101, and is also smaller than the diameter of the threads of the female thread 103a, which is the inner diameter of the screw hole portion 103. In other words, the communication hole 105 is smaller in diameter than the engagement hole 101. The engagement hole 101 and the communication hole 105 communicate with each other and penetrate the cathode member body 82 in the axial direction of the cathode member body 82.

[0038] The tip member 83 is a seamless, integrally molded product and has a tapered, approximately conical shape, with the outer diameter decreasing towards one end. Both the end face 83a on the axial end and the end face 83b on the axial end of the tip member 83 are circular. The outer diameter of the end face 83a on the axial end is smaller than the outer diameter of the end face 83b on the axial end. The tip member 83 has an outer circumferential surface 83c that connects the outer circumferential edge of end face 83a and the outer circumferential edge of end face 83b. The outer circumferential surface 83c has a smaller diameter towards the axial end face 83a.

[0039] The outer circumferential surface 83c has a streamlined shape that bulges radially outward with respect to the conical surface connecting end faces 83a and 83b. The outer circumferential surface 83c has an R-shape that bulges radially outward. The outer circumferential surface 83c has a shape obtained by rotating a circular arc that is convex in the direction away from the rotational axis, passing through two points that are at different axial positions and at different distances from the rotational axis.

[0040] The end faces 83a and 83b are flat surfaces extending perpendicularly to the central axis of the outer circumferential surface 83c. The centers of the end faces 83a and 83b pass through the central axis of the outer circumferential surface 83c. The outer diameter of the end face 83b is equal to the outer diameter of the main body 91 of the cathode member body 82, i.e., the diameter of the outer circumferential surface 91a. Also, the outer diameter of the end face 83b is equal to the outer diameter of the end face 94a of the joint 94.

[0041] The tip member 83 has a connecting hole 115 that is recessed from the end face 83b toward the end face 83a. The connecting hole 115 has an open hole portion 116 and a screw hole portion 117. The inner circumferential surface 116a of the opening 116 is cylindrical. The inner circumferential surface 116a is arranged coaxially with the end face 83b, with the central axis coinciding with it. The screw hole portion 117 has an internal thread 117a on its inner circumference. The internal thread 117a is arranged coaxially with the inner circumferential surface 116a of the open hole portion 116, with its central axis aligned with it. The inner diameter of the internal thread 117a, that is, the diameter of the threads of the internal thread 117a, is smaller than the inner diameter of the open hole portion 116, that is, the diameter of the inner circumferential surface 116a.

[0042] The tip member 83 has a discharge hole 118 that extends from the bottom surface 115a on the opposite side of the end surface 83b of the joining hole 115 to the end surface 83a. One end of the discharge hole 118 opens to the bottom surface 115a of the joining hole 115, and the other end opens to the end surface 83a. The inner circumferential surface 118a of the discharge hole 118 is cylindrical. The discharge hole 118 is arranged coaxially with the inner circumferential surface 116a of the opening hole portion 116 and the female thread 117a of the screw hole portion 117 of the joining hole 115, with their central axes aligned. In other words, the discharge hole 118 is formed coaxially with the joining hole 115, with their central axes aligned. The diameter of the inner circumferential surface 118a, which is the inner diameter of the discharge hole 118, is smaller than the diameter of the inner circumferential surface 116a, which is the inner diameter of the opening hole portion 116, and is also smaller than the diameter of the threads of the female thread 117a, which is the inner diameter of the screw hole portion 117. In other words, the discharge hole 118 is smaller in diameter than the joining hole 115. The joining hole 115 and the discharge hole 118 are in communication with each other and penetrate the tip member 83 in the axial direction of the tip member 83.

[0043] The protruding shaft portion 92 of the cathode member body 82 is inserted into the joining hole 115 of the tip member 83. At this time, the male thread 90a of the tip shaft portion 90 of the protruding shaft portion 92 is screwed into the female thread 117a of the screw hole portion 117 of the joining hole 115, thereby connecting the cathode member body 82 and the tip member 83 as shown in Figure 2. At this time, the end face 94a of the joining portion 94 of the cathode member body 82 and the end face 83b of the tip member 83 come into close contact with each other. As a result, the end faces 94a and 83b, which have the same outer diameter, are arranged coaxially. Consequently, the outer circumferential surface 91a of the main body portion 91 of the cathode member body 82 and the outer circumferential surface 83c of the tip member 83 become coaxial and continuous without any steps. In this way, the cathode member body 82 and the tip member 83 are connected and become one unit, forming the cathode member 81. The cathode member 81 is positioned at the radial center of the cathode member 81, with the engagement hole 101 and communication hole 105 of the cathode member body 82 and the joining hole 115 and discharge hole 118 of the tip member 83 coaxially aligned with their central axes.

[0044] The tip member 83 has a tapered tip portion 121 at the end opposite to the contact portion 93 of the cathode member 81, which is formed by connecting the cathode member body 82 and the tip member 83. The cathode member 81 has a contact portion 93 at one end in the axial direction, and a tapered tip portion 121 at the end opposite to the axial contact portion 93, with the outer diameter decreasing towards the side opposite the contact portion 93. The cathode member 81 has a metal cathode member body 82 including an engagement hole 101 and a contact portion 93, and a synthetic resin tip member 83 that forms the tapered tip portion 121. In the cathode member 81, the communication hole 105 of the cathode member body 82 connects the engagement hole 101 of the cathode member body 82 and the joining hole 115 of the tip member 83. The cathode member 81 has an outlet hole 118 in the tip member 83 that connects the joining hole 115 of the tip member 83 to the outside. Therefore, the engagement hole 101, the communication hole 105, the joining hole 115, and the outlet hole 118 of the cathode member 81 are connected in the axial direction of the cathode member 81 and penetrate the cathode member 81 in the axial direction of the cathode member 81. The cathode member 81 has an outlet hole 118 in the tapered tip portion 121.

[0045] Then, the small-diameter portion 58 of the rod 10 shown in Figure 1 is inserted into the engagement hole 101 of the cathode member 81 and housed there. At this time, the small-diameter portion 58 of the rod 10 is screwed into the female thread 103a of the screw hole portion 103 at the male thread 58a, and the outer surface 57a of the flange portion 57 comes into surface contact with the end face 93a of the contact portion 93, resulting in tight contact. In other words, the contact portion 93 of the cathode member 81, which extends radially outward from the engagement hole 101, comes into contact with the flange portion 57 of the rod 10. In this way, the cathode member 81 is attached to the rod 10 by engaging the small-diameter portion 58 of the rod 10 with the engagement hole 101.

[0046] As a result, the end face 93a and the outer surface 57a of the same diameter are arranged coaxially. Consequently, as shown in Figure 4, the outer circumferential surface 91a of the main body 91 of the cathode member 81 and the outer circumferential surface 55a of the large diameter portion 55 of the rod 10 become coaxial and continuous without any steps. In other words, the outer circumferential surface 91a, which is made up of the cylindrical surface of the main body 91 of the cathode member 81, and the outer circumferential surface 55a, which is made up of the cylindrical surface of the large diameter portion 55 of the rod 10 are arranged on the same cylindrical surface. After attaching the cathode member 81 to the rod 10 in this manner, the large diameter portion 55 of the rod 10 is plated.

[0047] The plating apparatus 131, which applies plating to a predetermined range of the large-diameter portion 55 of the rod 10, has a gripping part 132 of a transfer robot that grips the rod 10 with the cathode member 81 attached. The gripping part 132 grips the end of the large-diameter portion 55 of the rod 10 opposite to the cathode member 81. The gripping part 132 has a claw portion 133 that contacts the large-diameter portion 55 of the rod 10 and serves as an electrode. The gripping part 132 grips the rod 10 with the rod 10 extending vertically downward from the gripping part 132. The gripping part 132 is vertically movable. When the rod 10 is gripped by the gripping part 132, it is aligned vertically, and the cathode member 81 is positioned below the large-diameter portion 55.

[0048] The plating apparatus 131 includes a processing tank body 136 with an insertion opening 135 at its top into which a rod 10, which is gripped by a gripping portion 132 and descends together with the gripping portion 132, and a cathode member 81 can enter. The plating apparatus 131 also includes an electrode 142 inside the processing tank body 136, with an insertion opening 141 at its top into which a rod 10, which is gripped by the gripping portion 132 and descends together with the gripping portion 132, and a cathode member 81 can enter. The insertion opening 141 of the electrode 142 is positioned lower than the insertion opening 135 of the processing tank body 136. The electrode 142 is cylindrical, with its central axis aligned vertically. The electrode 142 also serves as the tank wall and is longer than the insertion length of the rod 10 and cathode member 81. The gripping portion 132 positions the rod 10 and cathode member 81 inside the electrode 142 so as to be coaxial with the electrode 142.

[0049] In the manufacturing method of the rod 10 of this embodiment, before plating the rod 10, the cathode member 81 is attached to the small diameter portion 58 of the rod 10 by automatic or manual means, so that the part to be processed 150 consists of the rod 10 and the cathode member 81.

[0050] The plating apparatus 131 grips the rod 10 of the part to be processed 150 with the gripping part 132, inserts the gripped part to be processed 150 into the insertion port 135 of the processing tank body 136 from above, with the cathode member 81 leading, and then inserts it into the insertion port 141 of the electrode 142 from above. Then, as shown in Figure 4, the gripping part 132 lowers the part to be processed 150 and stops it so that the large diameter portion 55 is inserted into the electrode 142 for a predetermined length. The part to be processed 150, gripped and stopped by the gripping part 132 in this way, is positioned coaxially with the electrode 142. In this state, the part to be processed 150 is positioned with the cathode member 81 below the rod 10.

[0051] The plating apparatus 131 flows the plating solution from bottom to top within the electrode 142, as shown by the dashed arrow in Figure 5, toward the part to be processed 150, which is stopped with the large diameter portion 55 inserted into the electrode 142 for a predetermined length. The plating solution then flows from below the cathode member 81 toward the cathode member 81 within the electrode 142, comes into contact with the cathode member 81, flows through the gap between the cathode member 81 and the electrode 142, and then flows through the gap between the large diameter portion 55 and the electrode 142. At this time, the cathode member 81 regulates the flow of the plating solution with its tapered tip portion 121 at the lower end. In other words, the cathode member 81 has a flow-rectifying structure with its tapered tip portion 121 at the lower end, and the tapered tip portion 121 suppresses turbulence of the plating solution. Therefore, the plating solution flows along the side of the outer circumferential surface 91a of the main body 91 of the cathode member body 82 in a rectified state by the tapered tip portion 121, and then flows along the side of the outer circumferential surface 55a of the large diameter portion 55.

[0052] Then, with the plating solution flowing continuously within the electrode 142 as described above, power is supplied between the contact point of the electrode claw portion 133 and the contact point of the electrode 142. As a result, the tip member 83, which is made of insulating synthetic resin material, does not undergo electrodeposition of plating, i.e., no plating layer is formed. Instead, plating is electrodeposited onto the outer circumferential surface 91a of the main body 91 of the metal cathode member body 82 and the outer circumferential surface 55a of the large diameter portion 55 of the metal rod 10, forming a plating layer. At this time, the plating solution enters the cathode member 81 through the discharge hole 118, but since the area around the small diameter portion 58 of the rod 10 is surrounded by the cathode member body 82, the plating current does not wrap around it, and therefore, no plating layer is formed on the small diameter portion 58 of the rod 10.

[0053] Here, since the main body 91 of the metal cathode member body 82 of the cathode member 81 is positioned below the large-diameter portion 55 of the rod 10, the current that would otherwise be concentrated in the lower part of the conductive metal portion can be concentrated in the cathode member body 82 located below the rod 10. This makes it possible to make the film thickness of the large-diameter portion 55 uniform.

[0054] When a plating layer of a predetermined thickness is formed on the large diameter portion 55, the plating apparatus 131 stops the plating solution flowing from below toward the cathode member 81 within the electrode 142. Then, the gripping portion 132 rises to lift the part to be processed 150, consisting of the rod 10 and the cathode member 81, from the electrode 142 and the processing tank body 136, discharge it for the next process, and then grips the part to be processed 150 to be plated.

[0055] In a subsequent process, the cathode member 81 is removed from the plated rod 10. The cathode member 81 removed from the rod 10 is cleaned to remove any deposits that adhered to it during the plating process, and then reused for plating.

[0056] By extending the lower end of the electrode 142 below the lower end of the cathode member 81, a rectifying effect on the plating solution can be obtained. In addition, the tapered shape of the cathode member 81 further improves the rectifying effect.

[0057] In this embodiment, the rod 10 and electrode 142 are arranged to extend vertically, but they are not limited to this and may be arranged to extend in any direction. For example, the rod 10 and electrode 142 may be arranged to extend horizontally. In such cases as well, the plating solution is configured to flow from the direction opposite to the end face 83a of the cathode member 81 toward the cathode member 81.

[0058] Patent Document 1, mentioned above, discloses a technique for performing plating by attaching a tapered cathode member to a rod. However, this cathode member has an engagement hole for engaging the rod, but if the plating solution enters the engagement hole, it may reduce productivity. For example, if the plating solution enters the engagement hole, it may hinder the engagement of the rod with the engagement hole, so it is necessary to drain the plating solution from the engagement hole before engaging the rod with the engagement hole.

[0059] In contrast, the cathode member 81 and the method for manufacturing the rod 10 using the same in this embodiment have a discharge hole 118 that can discharge the plating solution that has entered the engagement hole 101 that engages with the small diameter portion 58 of the rod 10. Therefore, the plating solution that has entered the engagement hole 101 can be discharged from the discharge hole 118. Thus, even if the plating solution enters the engagement hole 101, the entered plating solution can be smoothly discharged from the discharge hole 118. This reduces the amount of plating solution taken out of the processing tank body 136 and eliminates the need for work to discharge the plating solution, thereby suppressing a decrease in productivity.

[0060] Furthermore, the cathode member 81 consists of two parts: a cathode member body 82 and a tip member 83. The cathode member body 82 has a main body 91 that covers the small diameter portion 58 of the rod 10 and has an engagement hole 101 for engaging with the small diameter portion 58, and a protruding shaft portion 92 that protrudes from the main body 91. The tip member 83 has a joining hole 115 for joining the protruding shaft portion 92. The cathode member body 82 has a communication hole 105 that connects the engagement hole 101 and the joining hole 115 of the tip member 83, and the tip member 83 has a discharge hole 118 that connects the joining hole 115 to the outside. Therefore, even if the cathode member 81 consists of two parts, a cathode member body 82 and a tip member 83, the plating solution that has entered the engagement hole 101 of the cathode member body 82 can be smoothly discharged from the discharge hole 118 of the tip member 83 through the communication hole 105 of the cathode member body 82 and the joining hole 115 of the tip member 83. Thus, even if the cathode member 81 consists of two parts, a cathode member body 82 and a tip member 83, the amount of plating solution carried out of the processing tank body 136 can be reduced, and the work required to discharge the plating solution can be eliminated, thereby suppressing a decrease in productivity.

[0061] In this embodiment, the material of the cathode member body 82, which is the metal part of the cathode member 81, is titanium. However, any conductive metal other than titanium, such as iron, nickel, or stainless steel, can be used. Nevertheless, considering that it comes into contact with the plating solution, it is preferable to use titanium, which is resistant to the plating solution. If it is made of titanium, any deposits that adhere due to the plating process can be easily removed, making repeated use easier.

[0062] Furthermore, the tip member 83 is the part that forms a tapered tip 121 on the cathode member 81 that has low resistance to the plating solution jet, such as a streamlined shape, and its material is PTFE (polytetrafluoroethylene). However, any insulating synthetic resin can be used as the material for the tip member 83. However, like the cathode member body 82, it is preferable that it has high resistance to the plating solution. In addition to PTFE (polytetrafluoroethylene), other materials such as polyvinyl chloride and polyvinylidene fluoride can be used as the material for the tip member 83. [Explanation of symbols]

[0063] 10...Rod, 55...Large diameter section, 58...Small diameter section, 57...Flange section, 82...Cathode member body, 83...Tip section, 93...Contact section, 101...Engagement hole, 118...Discharge hole, 121...Tapered tip section.

Claims

1. Large diameter section and A smaller diameter portion having a smaller diameter than the aforementioned larger diameter portion, A method for manufacturing a rod having a flange portion connecting the large diameter portion and the small diameter portion, wherein plating is applied to the large diameter portion of the rod, An engagement hole that engages with the small diameter portion, A contact portion that extends radially outward from the engagement hole and contacts the flange portion, A tapered tip is provided at the end opposite to the contact portion, and its outer diameter decreases toward the opposite side of the contact portion, and it has a discharge hole that can discharge the plating solution that has entered the engagement hole, A method for manufacturing a rod, comprising attaching a cathode member having a certain property to the rod and flowing a plating solution toward the cathode member.

2. Large diameter section and A smaller diameter portion having a smaller diameter than the aforementioned larger diameter portion, A cathode member used when plating the large-diameter portion of a rod having a flange portion connecting the large-diameter portion and the small-diameter portion, An engagement hole that engages with the small diameter portion, A contact portion that extends radially outward from the engagement hole and contacts the flange portion, A tapered tip is provided at the end opposite to the contact portion, and the outer diameter becomes smaller towards the side opposite the contact portion, A discharge hole from which the plating solution that has entered the engagement hole can be discharged, A cathode member characterized by having the following features.

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