JPH05214596A - Structure of cathode part of electroplating device - Google Patents

Abstract

PURPOSE:To enable the application of full-surface plating at a uniform thickness to annular bodies to be plated, such as piston rings. CONSTITUTION:A cathode revolving shaft 1 has plural pieces of annular grooves 3 apart equally spaced intervals in the longitudinal direction of an outer peripheral surface 2. The annular grooves 3 are formed to the depth shallower than the thickness in the diametral direction of the annular bodies 10 to be plated. The cathode revolving shaft 1 is held horizontally rotatably and is rotated at the time of plating. An idle static shaft 7 is disposed in parallel above the cathode revolving shaft 1. Plural pieces of idle annular bodies 9 which have the bore larger than the outside diameter of the shaft 7 and are formed of nonconductive elastic materials on at least the outer peripheral surfaces are inserted via spacers 8 onto the above-mentioned shaft. The annular bodies 10 inserted into the annular grooves 3 of the cathode revolving shaft 1 are pressed by the own-weights of the idle annular bodies 9 and are pressed to come into contact with the cathode revolving shaft 1 at the time of plating. The annular bodies to be plated are thus plated between the idle annular bodies and anodes 6 while rotating together with the idle annular bodies 6 according to the rotation of the cathode revolving shaft 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroplating apparatus which is effective for use in the whole surface plating of an annular body such as a piston ring for an internal combustion engine (including a side rail of a combined oil ring and a coil expander). The structure of the cathode part.

[0002]

2. Description of the Related Art A plurality of annular grooves are formed at equal intervals in the longitudinal direction on the outer peripheral surface of a cathode shaft, and an annular body to be plated is inserted into these grooves. There was an idea to plate the entire surface of the plated annular body, but because the capacitance depends on the weight of the plated annular body itself, when performing light weight chromium plating with a large plating current such as a piston ring. Was not able to be adopted because the contact part was unstable and the electric capacity was insufficient.

Therefore, an energization method using elastic contacts is usually adopted. This elastic contact method is performed using the cathode jig 20 shown in FIG. The cathode jig 20 has a U-shaped cathode portion 21, and a plurality of sets of elastic contact members are provided on the opposing linear portions of the U-shaped cathode portion 21, respectively. The set of elastic contact members includes an elastic contact member 22 located on the upper side and an elastic contact member 23 located on the lower side. The elastic contact member 22 located on the upper side is formed of a copper wire material, and projects laterally from the cathode portion 21 and is divided into two forks. Elastic contact member 2
3 is also formed of a copper wire rod, projects laterally from the cathode portion 21, and has a tip portion which constitutes an elastic contact and faces downward.

When a piston ring is attached to the cathode jig 20 as the to-be-plated annular body 10, the abutment portion of the piston ring is slightly opened and fitted into the above three elastic contacts.
The elastic force of the piston ring locks the piston ring on the three elastic contacts. In this way, piston rings are attached to a plurality of sets of elastic contact members 22 and 23 provided on the opposite straight portions of the cathode jig 20, and the cathode jig 20 is mounted between the anodes in the plating tank. By arranging and energizing, the entire surface of each piston ring is plated with chromium, for example.

[0005]

The drawbacks of the plating method using the elastic contacts are as follows. The work of setting the to-be-plated annular body on the elastic contact is troublesome and the workability is poor. Since the to-be-plated annular body is stationary with respect to the elastic contact, the contact portion and other portions have different plating thicknesses. Since the plurality of to-be-plated annular bodies are arranged in the straight line portions of the cathode jig facing each other, the interval between the adjacent to-be-plated annular bodies is not constant with respect to each part of the circumference of the to-be-plated annular body.
As a result, the plating thickness becomes different. Due to the non-uniformity of the distance balance with the anode, the ring-shaped objects to be plated have different plating thicknesses.

An object of the present invention is to easily mount a to-be-plated annular body on a cathode portion, to plate the entire surface of the to-be-plated annular body, and to determine the plating thickness of the to-be-plated annular body itself and a plurality of to-be-plated bodies. An object of the present invention is to provide a cathode part structure of an electroplating apparatus capable of reducing the difference in plating thickness between annular bodies.

[0007]

The cathode part structure of the electroplating apparatus of the present invention has a plurality of annular grooves on the outer peripheral surface at equal intervals in the longitudinal direction, and the annular grooves are the annular plates to be plated. A horizontal cathode rotating shaft having a depth shallower than the radial thickness of the body, an idle stationary shaft arranged in parallel above the cathode rotating shaft, and an idle stationary shaft movably inserted into the idle stationary shaft. And a plurality of idle annular bodies each having at least an outer peripheral surface formed of a non-conductive material.

It is preferable that the idle annular body has a width for pressing one plated annular body or two adjacent annular bodies to be plated.

At least the outer peripheral surface of the idle annular body is preferably made of a non-conductive elastic material.

[0010]

A plurality of annular bodies to be plated, which are mounted in the annular groove of the cathode rotating shaft and arranged at equal intervals on the cathode rotating shaft, are idle inserted in the idle stationary shaft arranged above the cathode rotating shaft. The annular body is pressed by its own weight, and the inner peripheral surface of the plated annular body is pressed against the outer peripheral surface of the cathode rotating shaft.

As described above, since the to-be-plated annular body is pressed against the cathode rotating shaft, the contact portion becomes stable. And, since the idle annular body is pressed by its own weight, even if there is a variation in the radial thickness of each plated annular body, the variation in the thickness can be absorbed, and the cathode rotation of each plated annular body The pressing force on the shaft can be made uniform.

When the cathode rotating shaft rotates, the plated annular body is rotated, and at the same time, the idle annular body is also rotated and the contact portion between the cathode rotating shaft and the plated annular body always moves.

As described above, the annular members to be plated are arranged at equal intervals on the cathode rotating shaft so that they can be pressed against the cathode rotating shaft with a uniform force, and the contacts are rotated by the rotation of the cathode rotating shaft. Since it constantly moves, it is possible to reduce inconsistency in the plating thickness of the to-be-plated annular body itself and the plating thickness of a plurality of to-be-plated annular bodies.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, the cathode rotating shaft 1 is made of copper or a copper alloy, and a plurality of annular grooves 3 are formed on the outer peripheral surface 2 at equal intervals in the longitudinal direction. The depth of the annular groove 3 is formed to be shallower than the radial thickness of an annular body to be plated such as a piston ring, and the outer peripheral surface other than the annular groove 3 is covered with an insulating film. The sectional shape of the annular groove 3 is U
The shape is not limited to a V shape, a V shape, or a rectangular shape, but it is preferable to adopt a shape corresponding to the cross-sectional shape of the object to be plated. For example, if the cross-sectional shape of the object to be plated is circular, it should be U-shaped or V-shaped (for example, if the object to be plated is a coil expander, etc.), and if the cross-sectional shape of the object to be plated is rectangular, it should be rectangular. It suffices (for example, when the object to be plated is a compression ring with a rectangular cross section).

The cathode rotating shaft 1 is horizontally held in the plating tank 5 and is configured to be rotated by a rotation driving means (not shown), and at the time of rotation, it can be constantly energized by an energizing means (not shown). It is configured. In the plating tank 5, a plurality of anodes 6 are arranged on both sides of the cathode rotating shaft 1. The anodes 6 are vertically provided at equal intervals in the longitudinal direction of the cathode rotating shaft 1.

An idle stationary shaft 7 is provided above the cathode rotating shaft 1 in parallel with the cathode rotating shaft 1. A large number of spacers 8 of the same size are fitted on the idle stationary shaft 7 at equal intervals, and idle annular bodies 9 are inserted between the spacers 8 of the idle stationary shaft 7. All of these idle annular bodies 9 have the same shape, material and weight.

At least the outer peripheral surface of the idle annular body 9 is formed of a non-conductive elastic material. For example, the metal ring is formed by coating the outer periphery of the metal ring with a resin (fluorine resin or the like), or by forming the entire annular body with a resin (fluorine resin or the like). The idle annular body 9 has an inner diameter larger than the outer diameter of the idle stationary shaft 7, and is configured to be able to move freely with respect to the idle stationary shaft 7. As shown in FIG. , Which is in a state of hanging from the idle stationary shaft 7, floats from the idle stationary shaft 7 during plating, presses the plated annular body 10 inserted into the annular groove 3 of the cathode rotating shaft 1 by its own weight, and 1
The inner peripheral surface of 0 acts so as to be pressed against the outer peripheral surface of the annular groove 3 of the cathode rotating shaft 1. In this case, each plated annular body 10
In order to be uniformly pressed against the outer peripheral surface of the annular groove 3 of the cathode rotation shaft 1, the axial length of the idle annular body 9 is such that the two adjacent annular bodies 10 to be plated are in contact with each other ( (See FIG. 1) or a length (see FIG. 4) that abuts against one annular member 10 to be plated.

The idle stationary shaft 7 is constructed so that it can move up and down, and it descends to a predetermined position during plating, and the idle annular body 9 is inserted into the annular groove 3 of the cathode rotating shaft 1 as described above. The annular body 10 to be plated is configured to be pressed by its own weight.

A case will be described below in which the compression ring is plated on the entire surface of the compression ring using the above apparatus.

First, the compression ring 10 is inserted into each annular groove 3 of the cathode rotating shaft 1. The cathode rotating shaft 1 equipped with the compression ring 10 is set in the plating tank 5. Next, when the idle stationary shaft 7 is lowered to a predetermined position, the idle annular body 9 moves to the compression ring 10.
Is pressed against the outer peripheral surface of the idle floating shaft 7 and floats from the idle stationary shaft 7, and the compression ring 10 is pressed by the dead weight of the idle annular body 9 to
The inner peripheral surface of is pressed against the outer peripheral surface of the annular groove 3 of the cathode rotating shaft 1.

Then, the cathode rotating shaft 1 is rotated by a rotation driving means (not shown), and the anode 6 and the cathode rotating shaft 1 are energized by energizing means (not shown). As a result, the outer peripheral surface and the upper and lower surfaces of the compression ring 10 are plated. In this case, when the cathode rotating shaft 1 is rotated, the compression ring 10 pressed against the cathode rotating shaft 1 by the idle annular body 9 also rotates and the idle annular body 9 also rotates.

Therefore, since the compression ring 10 rotates during plating, the contact point with the cathode rotating shaft 1 always moves. Therefore, the compression ring 10
It is possible to reduce the disparity in the plating thickness of oneself.

In addition, during plating, the plurality of compression rings 10 are arranged at equal intervals along the cathode rotating shaft 1, so that the intervals between the adjacent compression rings 10 are constant and uneven plating thickness is reduced. it can.

Further, due to the weight of the idle annular body 9,
Since the compression rings 10 are pressed, even if there are variations in the radial thickness of the plurality of compression rings 10, the variations in the thickness can be absorbed, and each compression ring 10 exerts a uniform force on the cathode rotating shaft 1. It is pressed. Therefore, a plurality of compression rings 1
It is possible to reduce the difference in plating thickness between 0s.

In the above embodiment, the idle stationary shaft 7 is used.
The idle ring members 9 are arranged on the
A plurality of annular grooves may be formed at equal intervals in the longitudinal direction on the idle stationary shaft, and the idle annular body may be movably inserted into each of these annular grooves.

Further, in the above embodiment, the entire surface of the compression ring 10 is plated, but when plating a part of the surface, the non-plated portion may be masked. For example, when plating the upper and lower surfaces, the outer peripheral surface may be masked.

Further, although this device has been shown as an example applied to a compression ring, other objects such as piston rings (including side rails of combined oil rings, coil expanders, etc.) are to be plated and are annular bodies. If applicable, it can be applied.

Hereinafter, a description will be given of a coil expander of a combined oil ring, in which the entire surface is plated with chromium by using the comparative example and the plating apparatus according to the present invention.

The contents of the coil expander are as follows. Wire diameter: 1φmm Coil outer diameter: 3φmm (pitch 1.5mm) Overall length: 345.4mm Material: Carbon steel

This coil expander was plated with chromium as follows. (Comparative Example) One end of a linear coil was held, suspended between anodes, energized, and chromium-plated by a conventional method. The plating conditions were such that the distance between the objects to be plated was 20 mm, 30 pieces were simultaneously plated, and the plating current was 500 A and the plating time was 25 minutes. (Comparative Example) Both ends of the coil were jointed as in a state of use to form a ring having a diameter of 110 mm, and the coil was held in the cathode jig of the elastic contact method described with reference to FIG. 7 for plating. Plating conditions are 1 row for 2 rows and 5 rows for each rack.
There were 10 racks, and 3 racks were hung simultaneously between the anodes, and the plating current was 500 A and the plating time was 25 minutes. The distance between the objects to be plated was 20 mm in one rack and the distance between the racks was 50 mm. (Example) Both ends of the coil were jointed as in a state of use to form an annular shape of 110 mm, and the coil was applied to the plating apparatus according to the present invention. 15 to 20 mm between plated objects, 30
The books were simultaneously plated, the rotation speed of the cathode rotating shaft was 1 mm / sec, the plating current was 500 A, and the plating time was 25 minutes.

Outer diameters at 9 locations in each plated product plated as described above were measured, and the plating thickness distributions were compared (n = 30).

[0032]

[Table 1]

In the comparative example, the plating thickness of the central portion is thin,
Plating pitting occurs at the lower end, and the difference in plating thickness is large. Also, the loss of plating speed is large. In the case of the comparative example which is usually carried out, the electric resistance of the object to be plated is high, and the current distribution is non-uniform when energized in only one direction, and uniform plating cannot be performed. Therefore, as in the conventional method, it is necessary to take out the tank during the plating, and to change the holding and reversing, and the work efficiency is poor.

In the comparative example, the difference in the plating thickness within one piece is smaller than that in the comparative example, but it is 1 due to the influence of the difference in the distance between the object to be plated and the anode because the contact is stationary.
The local unevenness of the plating thickness is large, and the increase in the outside diameter before plating (σ) is about twice as large, which is insufficient.

In the examples, the difference in the plating thickness is small, and the increase in the outer diameter before plating (σ) is 1.2 times, which is very small.

Next, regarding the compression ring,
An example will be described in which the upper and lower surfaces are plated with chrome using the comparative example and the plating apparatus according to the present invention.

The contents of the compression ring are as follows. Width (B dimension): 4.0 mm Thickness (T dimension): 5.0 mm Outer diameter: 110φ mm Free contact gap: Approx. 10 mm Material: Spheroidal graphite cast iron

This compression ring was plated with chrome as follows. (Comparative Example) The plating was carried out while holding the elastic contact type cathode jig described with reference to FIG. The plating conditions were two racks horizontally and five rows vertically, ten racks per rack, and three racks were simultaneously hung between the anodes, and the plating current was 500 A and the plating time was 60 minutes. 20m in one rack between plated objects
m and the distance between racks was 50 mm. (Example) The plating apparatus according to the present invention was used. Between the objects to be plated, 15 to 20 mm, 30 pieces were simultaneously plated, the rotation speed of the cathode rotating shaft was a moving amount of 1 mm / sec, the plating current was 300 A, and the plating time was 60 minutes. (Example) As shown in FIG. 5, after fitting the to-be-plated annular body 10 to the inner circumference of the closed toroidal body 11 having the same width dimension (B dimension) as the to-be-plated annular body 10, The plating was performed in the same manner as in the example. In addition, when the annular body 10 to be plated is fitted into the closed annular body 11, the gap between the annular bodies 10 to be plated is 1 to 2 mm.

The width dimension (B dimension) at 9 locations in each plated product plated as described above was measured, and the plating thickness distributions were compared (n = 30). As shown in FIG. 6 (b), the measurement point is a point where the abutting end portions on both sides and other peripheral portions are divided into approximately eight equal parts. FIG. 6A shows a graph of the measurement results.

[0040]

[Table 2]

In the comparative example and the example which are usually carried out, the difference in the plating thickness (σ) is large because of the local excessive plating thickness of the abutment portion which is the characteristic of the plating. But,
It can be seen that the increase in the non-uniformity (σ) of the plating thickness other than the abutment portion is 2.6 times in the comparative example and 1.5 times in the example of the present invention, which is an improvement.

In the example, the non-uniformity (σ) of the plating thickness including the abutting part is reduced by 1.3 times, which is a great improvement, because the object to be plated is a substantially complete ring. ..
Further, the distribution of the plating thickness is made uniform, and the effect of improving the overall plating speed is also recognized.

[0043]

As described above, according to the present invention, the outer peripheral surface has a plurality of annular grooves at equal intervals in the longitudinal direction, and the annular grooves have a radial thickness of the to-be-plated annular body. A horizontal cathode rotating shaft having a shallower depth than that, an idle stationary shaft arranged in parallel above the cathode rotating shaft, and the idle stationary shaft is movably inserted into the idle stationary shaft,
Since at least the outer peripheral surface is provided with a plurality of idle annular bodies formed of a non-conductive material, each annular body to be plated is arranged at equal intervals on the cathode rotating shaft, and the cathode is rotated by a uniform force. Since it can be pressed against the shaft and the contact is constantly moved by being rotated by the rotation of the cathode rotating shaft, it is possible to reduce the difference in the plating thickness of the to-be-plated annular body itself and the plating thickness of a plurality of to-be-plated annular bodies. ..

[Brief description of drawings]

FIG. 1 is a plan view showing a plating apparatus of the present invention.

FIG. 2 is a vertical sectional view showing a plating apparatus of the present invention.

FIG. 3 is a cross-sectional view showing an idle stationary shaft and an idle annular body during non-plating.

FIG. 4 is a plan view showing another example of the idle annular body and corresponding to FIG. 1 (however, the plating tank is omitted).

FIG. 5 is a plan view showing an annular body to be plated fitted to the inner periphery of a closed annular body.

FIG. 6A is a graph showing a result of measuring a plating thickness when a compression ring is plated with chrome;
(B) is an explanatory view showing a measurement point.

FIG. 7 is a front view showing a conventional cathode jig.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 cathode rotating shaft 2 outer peripheral surface 3 annular groove 5 plating tank 6 anode 7 idle stationary shaft 8 spacer 9 idle annular body 10 annular body to be plated 11 closed annular body

Claims (3)

[Claims] 1. A horizontal surface having a plurality of annular grooves on the outer peripheral surface at equal intervals in the longitudinal direction, the annular grooves having a depth shallower than the radial thickness of the to-be-plated annular body. A cathode rotating shaft, an idle stationary shaft arranged in parallel above the cathode rotating shaft, and a plurality of idle shafts that are movably inserted in the idle stationary shaft and at least an outer peripheral surface of which is formed of a non-conductive material. And an idle annular body of 1. The cathode part structure of the electroplating apparatus. 2. The cathode part structure of an electroplating apparatus according to claim 1, wherein the idle annular body has a width for pressing one plated annular body or two adjacent plated annular bodies. .. 3. The cathode part structure of an electroplating apparatus according to claim 1, wherein at least an outer peripheral surface of the idle annular body is formed of a non-conductive elastic material.