JPH0356689A - Device for plating metallic cylinder with chromium - Google Patents

Abstract

PURPOSE:To form a Cr plating film excellent in wear resistance in uniform thickness at the time of plating the inner surface of an Al cylinder with hard Cr by accurately and concentrically setting a columnar anode fixed to the tip of a jig in the cylinder and applying a current. CONSTITUTION:The wear resistance of the inner surface of a cylinder of Al or an Al alloy for a lightweight internal combustion engine is improved as follows. Namely, a guide and conductor plate fixed to a jig 5 is inserted into a machine screw 2 temporarily fixed to the side surfaces of plural Al-based metallic cylinders 4 and fixed. The columnar anode 1 fixed to the jig 5 is simultaneously inserted into each cylinder 4 accurately and concentrically, a current is applied between the anode 1 and the conductor plate, and a hard Cr plating layer is formed on the inner surface of the cylinder 4 in uniform thickness. Since the jig 5 is used, the hard Cr plating layer hardly worn by the sliding of a piston is formed on the inner surface of the cylinder with this simple process in good yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application 1] The present invention relates to an apparatus for chrome plating the inner surface of a metal cylinder, particularly a cylinder of an internal combustion engine made of aluminum or aluminum alloy.

[Prior art and its problems] Aluminum and aluminum alloys have excellent physical and mechanical properties, such as mechanical strength, thermal conductivity, and light weight, and are particularly suitable as die-casting alloys. Suitable for producing internal combustion engine cylinders, it is widely used in relatively small engines for vehicles and agricultural machinery.

The only disadvantage of using aluminum and aluminum alloy cylinders is poor wear resistance, but to compensate for this, it is common practice to plate the cylinder bore with hard chrome.

Conventionally, for hard chrome plating on the inner surface of aluminum or aluminum alloy cylinders, corrective polishing of the inner surface after plating is essential to ensure dimensional accuracy.

For example, required quality characteristics include inner diameter dimension, roundness,
There are various factors such as cylindricity, and the permissible accuracy range for each of these methods is on the order of several microns, so it is impossible to ensure that accuracy by plating as is by the usual method. Therefore, the final finish required thickness is usually 4 to 5 times (for example, 200 to 250 microns) the required thickness (for example, 50 microns).
This is a very uneconomical method, such as plating to a thickness of microns) and then grinding away most of the electrodeposited deposits using an internal grinding machine using a grindstone to ensure the desired dimensional accuracy. It is produced in

In other words, in many conventional plating jigs for cylinders, the anode is not fixed but is in a free state, so it takes time to set the center, and it is not possible to confirm accuracy, making it easy to create dimensional defects. Ta.

As a result, we are forced to waste a lot of money, including the cost of raw materials and chemicals needed to apply thick plating, electricity costs, plating man-hours, grinding wheel consumption costs, and grinding man-hours.

In addition, in the plating process, conventional hard chrome plating on cylinders requires excessive plating thickness, so electrolysis is usually performed at high currents and for long periods of time. Therefore, the cylinder is set in a stationary jig and energized. After the contacts are fixed, plating is applied intermittently in a static bath for 5 to 15 hours, and the grinding process is added to this, which is extremely inefficient.

[Means for Solving the Problems] To achieve this, a high-viscosity thin plating is applied to the inner surface of the cylinder from the beginning, and the process is performed continuously.

As a result of extensive studies by the present inventors on this point, the cylinder plating jig has been designed to allow the cylinder to be plated to be accurately set to the true center of the cylindrical fixed anode. It has a structure that can be quickly persuaded with one touch, and the entire process includes pre-treatment process, plating process,
This purpose was achieved by configuring the assembly line work using the so-called tact method, which is organized so that the time required for each process, such as the cylinder attachment/detachment process, is the same.

That is, the present invention has the following features: 1> A means for supplying current to a cylindrical anode and a cylinder to be plated, and a means for locking to a KIP lever that is electrically connected to the said means for supplying power and capable of moving continuously or intermittently. A chrome plating apparatus for a metal cylinder, characterized by comprising a jig and means for fixing the cylinder to the jig so that the cylindrical anode is housed in the center of the cylinder, 2>Refer to 1> above. The means for energizing the cylinder to be plated consists of a screw-cum-energizing plate that is temporarily fixed to the cylinder in advance, and when the screw of the cylinder is guided and stopped by the guide, the cylindrical anode is located at the center of the cylinder. 3) The jig described in 1> above is locked to the carrier par, and the carrier par is energized while being slid and transferred. Continuous chrome plating equipment for metal cylinders, characterized in that the inner surface of the cylinder is plated, and 4. The means for energizing the cylinder to be plated as described in 1 above is a screw guide and energizing plate temporarily fixed to the cylinder in advance. Continuous chrome plating apparatus for metal cylinders according to 3) above, wherein when the screw of the cylinder is guided and stopped by the guide, the cylindrical anode is fixed in the center of the cylinder parallel to the inner wall surface of the cylinder. It is.

[Embodiments of the invention] Embodiments of the present invention will be described below based on the accompanying drawings.

A device according to the present invention (hereinafter abbreviated as “this device”). } first
The feature of this is that the cylinder is fitted with a single-method eyepiece with high precision, and the second feature is that it is a method that can be mass-produced continuously. This has resulted in various benefits by minimizing the amount of finish grinding and minimizing the plating thickness.

FIG. 1(a) is a perspective view showing a jig used in this apparatus, and FIG. 1(b) is a perspective view showing an example of a cylinder to be chrome plated.

The jig 5 includes one or more (four in FIG. 1(a)) cylindrical anodes 1, a metal plate installed on the back side of the anode casing which is a means for supplying electricity to the anodes, and a metal plate on the side surface of the casing. It is equipped with a cylinder guide member that serves as a current supply plate for the number of cylinders corresponding to the number of anodes.

The energizing metal plate and the energizing plate/cylinder guide member are each connected to two energizing bars that are insulated from each other, and the other end of each energizing bar is connected to the bar while sliding the jig. It has a hook shape that can be locked to a carrier bar that is energized.

In addition, when the current-carrying plate/cylinder member is fixed in advance by guiding the screw temporarily fixed to the cylinder into the cylinder groove, the cylindrical anode is located at the center of the cylinder and parallel to the inner wall surface of the cylinder. Only the anode corresponding to the anode is provided in a precisely fixed position.

That is, in the present invention, the positive 4! ! The positional relationship between the screw guide and the energizing plate is set for each type of cylinder according to the size, shape, etc. of the cylinder that is the plating material.

The cylinder may be temporarily fastened using screw holes for connection with the internal combustion engine, etc. to which this cylinder is applied, or a separate screw hole exclusively for temporary fastening may be provided at an appropriate position. You can stop there.

This screw can be quickly removed with one touch.

In conventional chrome plating equipment, the cylindrical anode is manually placed in the center of the cylinder while visually checking it, and since the anode is often free rather than fixed, it takes time to set the anode, and accuracy is required. Because of the eccentricity of the anode, the length of the plating was naturally uneven, and the thickness was uneven, making it impossible to obtain the required dimensional accuracy and making it easy to produce dimensional defects.

In the jig according to the present invention, the screw 2 temporarily fixed to the cylinder port portion is slid into the guide groove of the guide plate 3 which also serves as a current-carrying contact, and then screwed into position. By this method, a position relative to the fixed anode 1 without deviation is ensured and the setting is completed.

In this way, the cylinder can be attached and detached accurately with only one screw operation, and this, combined with the adoption of the slite transfer method of the jig using a carrier bar described below, enables continuous mass production of chrome joints.

That is, another point that enables the apparatus of the present invention to continuously produce hard chrome plating is the sliding power supply mechanism.

FIG. 2 is a front view of the jig 5, in which the fixed anode is set in the center of the small cylinder A, in a plating tank, and is locked to the 4-jar bar. In the figure, 6 indicates a sliding contact, 7 indicates a plating tank in which a carrier bar 8 is fitted, and 9 indicates a carrier bar moving mechanism.

FIG. 3 is a plan view of the entire plating apparatus, showing a large number of carrier bars that continuously move the cylinders after they are set on a jig at the cylinder removing station 10, which consists of a continuously moving conveyor. A jig is hooked onto a carrier bar on a conveyor 11 and goes through an immediate pre-treatment process 12, and then enters a plating process 14 consisting of a chrome plating tank via a reciprocating tracker 13, and after plating is completed, the cylinder is removed from the removal station 1.
The cycle of returning to zero is repeated, or in this case the carrier bar is transported continuously in a tact manner as described above.

[Effects of the Invention] According to the above-described structure, in the jig according to the present invention, the screw 2 temporarily fixed to the cylinder boat part can be used as the guide plate 3 which also serves as a current-carrying contact. ' Slide into the inner groove and tighten the screws. With this method, fixed electricity 4f
A position relative to A1 without deviation is ensured, and the setting is completed.

In this way, the cylinder can be attached and detached accurately with just one screw operation, so even if it is a stationary type like the conventional type, it can be plated uniformly to the desired thickness, and continuous mass production is also possible.

In other words, in the continuous chrome plating device according to the present invention, an FA structure as shown in FIG. 2 is adopted for continuous power supply. Electricity is continuously applied to the carrier bar being transferred by this sliding power feeding mechanism, and a predetermined plating thickness is ensured when the cylinder, which is the object to be plated, reaches the end point of the transfer.

Moreover, since the carrier bars are transferred sequentially through a continuous tank, deviations in liquid composition and energization conditions are averaged out, and variations between carrier bars are eliminated, making it possible to obtain plating with good dimensional accuracy. Since the dimensional accuracy is high after plating, there is almost no need for grinding for correction, and a finished product can be obtained by honing only a few microns to adjust the surface phase.

Therefore, the required plating thickness can be kept to the minimum necessary,
Since excessive plating and grinding for dimensional correction can be omitted, productivity is significantly improved. First, an example based on the present invention and a comparative example based on a conventional method will be presented to supplement the explanation.

[Brief explanation of drawings]

Figure 1(a) is a perspective view of an example of a jig used in the device of the present invention, Figure 1(b) is a perspective view of an example of a cylinder to be chrome plated, and Figure 2 is a jig. Fig. 3 is a front view of the plating tank and the key/rear bar set with the plating tank set therein, and Fig. 3 is a plan view showing the arrangement of the continuous plating apparatus. Symbols in the figure: 1... Fixed anode; 2... Screws: 3... Guide and energizing plate: 4... Cylinder; 5...
Jig; 6...Sliding contact; 7...Gear bar; 8...Plating tank; 9...Ki-V lever moving ramming structure; 10...Cylinder nb landing place; 11...
Conveyor; 12... Pretreatment process; 13... Traverser; 14... Plating process.

Claims (1)

[Scope of Claims] 1) A jig comprising means for supplying electricity to a cylindrical anode and a covered cylinder, and means for locking to a carrier bar that is electrically connected to the said supply means and can move continuously or intermittently. A chromium plating apparatus for a metal cylinder, comprising: a tool; and means for fixing the cylinder to a jig so that the cylindrical anode is housed in the center of the cylinder. 2) The means for energizing the fitted cylinder consists of a screw guide and energizing plate that is temporarily fixed to the cylinder in advance, and when the screw of the cylinder is guided to the guide and stopped, the cylindrical anode is inside the cylinder. 2. The chrome plating device for a metal cylinder according to claim 1, wherein the chrome plating device is fixed at the center of the cylinder parallel to the inner wall surface of the cylinder. 3) A continuous chrome plating apparatus for metal cylinders, characterized in that the jig according to claim 1 is locked to a carrier bar, and the carrier bar is energized while being slid and transferred to plate the inner surface of the cylinder. 4) The means for energizing the fitted cylinder consists of a screw guide and energizing plate temporarily fixed to the cylinder in advance, and when the screw of the cylinder is guided to the guide and stopped, the cylindrical anode is inside the cylinder. 4. The continuous chrome plating apparatus for metal cylinders according to claim 3, wherein the continuous chrome plating apparatus is fixed at the center of the cylinder parallel to the inner wall surface of the cylinder.