JP3396170B2 - Composite plating method for cylinder block - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite plating method for a cylinder block, more specifically, a composite plating layer having a uniform thickness and a uniform strength is formed on the inner peripheral surface of a cylinder constituting an engine. The present invention relates to a composite plating method for a cylinder block capable of performing the above.

[0002]

2. Description of the Related Art Conventionally, for example, when a cylinder constituting an automobile engine is manufactured from an aluminum alloy,
A technique has been adopted in which a sleeve having excellent wear resistance is cast on the inner peripheral surface of the cylinder bore, or a composite plating layer is applied to the inner peripheral surface to improve the wear resistance against sliding of the piston.

Examples of this type of composite plating layer include:
It is already known to use nickel sulfate in which fine particles of silicon carbide are dispersed and to perform so-called Nikasil plating. In order to form this kind of composite plating layer, the present applicant has already disclosed the invention "composite plating apparatus" in JP-A-7-157895 and the invention "inner circumference of hollow member" in JP-A-7-188990. "Composite plating method for surfaces" has been proposed.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in relation to the above-mentioned composite plating method and composite plating apparatus, and when performing composite plating on the inner peripheral surface of a cylinder bore,
Cylinder block composite plating method capable of depositing the eutectoid amount of the components forming the composite plating layer as uniformly as possible along the surface thereof, and making the coating hardness of the plating more uniform The purpose is to provide.

[0005]

In order to achieve the above object, the present invention inserts an electrode into a cylinder bore formed in a cylinder block and circulates and supplies a composite plating solution to the inner peripheral surface of the cylinder bore. In the method for forming a composite plating layer, the composite plating solution contains a nickel sulfate solution and silicon carbide , and the composite plating solution has a temperature of the composite plating solution.
And the pH, the presence or absence of plating burn of the plating formed,
A table in which the relationship between toughness and eutectoid efficiency was entered
The plating formed under the control of the CPU it has
Out of the burnt area, out of the high toughness area, and the eutectoid efficiency
Adjusted so as to be outside the area of 90% or less
And then the temperature is 45 ° C to 57 ° C and the pH is 1.7 to 2.7.
Is supplied to the cylinder block .

As a result, a composite plating layer having a uniform thickness and a uniform strength on the inner peripheral surface of the cylinder bore and having a suitable toughness can be obtained.

According to the present invention, the composite plating solution is stored in a composite plating solution storage tank, and the temperature is controlled in the range of 45 ° C to 57 ° C by temperature adjusting means arranged in the composite plating solution storage tank. It is characterized by

According to the present invention, the composite plating solution is stored in the composite plating solution storage tank, and the pH value of the composite plating solution is 1.7 to 2. It is adjusted to a range of 7.

Further, the present invention is characterized in that when the pH value of the composite plating solution is out of the range of the set pH value, fine particles of nickel carbonate are metered into the composite plating solution storage tank. To do.

In the present invention, the composite plating solution achieves temperature control and pH value control in the storage tank, and since the plating solution itself is uniform and constant, a better composite plating layer can be obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding the composite plating method for a cylinder block according to the present invention, as a preferred embodiment, an apparatus for applying a composite plating layer to the inner peripheral surface of the cylinder bore of a cylinder of a motorcycle is illustrated, and the composite plating is performed. The details of the method will be described below.

In FIG. 1, reference numeral 10 indicates a composite plating apparatus for carrying out the composite plating method according to the present embodiment, and the composite plating apparatus 10 includes a base plate 12
The first jig 14 provided on the base plate 12 and the base plate 12
1, a plurality of guide posts 16 standing upright, a slider 18 that moves in the vertical direction in FIG. 1 by a drive source (not shown) along the guide posts 16, and this slider 18
And an elevating frame 20 fixed to the. In the lifting frame 20,
The second jig 22 is attached.

An elongated electrode rod 24 having a hemispherical tip is formed in the second jig 22 and extends through the hole of the second jig 22. Therefore, when the slider 18 moves up and down under the action of a drive source (not shown), the second jig 22 is movable together with the electrode rod 24 by the elevating frame 20 in the vertical direction in FIG. It's easy to understand.

The electrode rod 24 is connected to the + side terminal of the DC power source 26. In this case, the motorcycle cylinder W as a work is sandwiched between the first jig 14 and the second jig 22, and the opening of the cylinder W has, for example, a seal unit 28a, It can be sealed by 28b. It should be noted that other openings (not shown) of the cylinder W are also closed by the same seal member as the seal units 28a and 28b. The cylinder W is electrically connected to the-side terminal of the DC power supply 26 via the conductor 30 electrically isolated from the second jig 22.

By the way, one end of a supply pipe 34 for supplying a composite plating solution, which will be described later, to the first jig 14 is connected to the first jig 14 through a tapered hole 32 of the first jig 14. It The other end of the supply pipe 34 is connected near the bottom of the composite plating solution storage tank 36. In fact, supply pipe 3
4, a pump 38 for supplying a plating solution and a flow meter 40 are provided, and the supply pipe 34 further includes a branch pipe 44.
Are connected. An end of the branch pipe 44 is connected to an air compressor 46, and the branch pipe 44 has an air flow meter 48 for measuring the amount of air supplied from the air compressor 46 and an air flow rate. The regulating valve 42 is connected. Here, the branch pipe 44
In addition to air, other inert gas such as helium gas, argon gas, or nitrogen gas may be supplied to.

Next, the composite plating solution storage tank 36 will be described.

The composite plating solution storage tank 36 stores the composite plating solution 50 therein. In this case, the composite plating solution 5
As 0, for example, 400 g of nickel sulfate, 35 g of boric acid and 55 g of fine particles of silicon carbide are added to 1 liter of water, and 3 g of saccharin sodium is turbid as a brightening agent. A rotary drive source, preferably a motor 52, is mounted on the upper portion of the composite plating solution storage tank 36, and a stirring blade 56 is fixed to the tip of a rotary shaft 54 extending from the motor 52 into the composite plating solution storage tank 36. is doing. The stirring blade 56 is located near the bottom of the composite plating solution storage tank 36 and substantially faces the vicinity of the tip of the supply pipe 34.

Further, a return pipe 58 extending from the second jig 22 is connected to the upper portion of the composite plating solution storage tank 36. This return pipe 58 is used to plate the inner peripheral surface of the cylinder W again after the composite plating solution 50 supplied from the composite plating solution storage tank 36 via the supply pipe 34 is used. It is for circulating the composite plating solution storage tank 36.

In the present embodiment, the heater 60 is fixed to the center of the inner peripheral surface of the composite plating solution storage tank 36, and the cooling tube 62 is wound in a coil shape so as to face the heater 60. Is fixed. Cooling tube 62
Is connected to a cooler 70 provided outside the composite plating solution storage tank 36. The cooler 70 has a heat exchanger (not shown) for exchanging heat with the refrigerant, a drive source, a switching valve, etc. including. A temperature sensor 64 for energizing or deactivating the heater 60 depending on the temperature of the composite plating solution 50, preferably a thermocouple, faces the composite plating solution storage tank 36. A pH sensor 66 for detecting the pH value of the composite plating solution 50 is fixed inside.

The temperature sensor 64 is connected to the temperature controller 68, and as described above, detects the temperature of the composite plating solution 50 and outputs a detection signal thereof to the temperature controller 6.
Send to 8. The heater 60 is energized / deenergized via the temperature controller 68 by this detection signal. The heater 60, the cooling tube 62, the temperature sensor 64, the temperature controller 68, the cooler 70, etc. constitute a temperature adjusting means for the composite plating solution 50. Therefore, drive control of the heater 60 and the cooler 70 is performed by the energizing / disabling signal sent from the temperature controller 68 according to the detection signal of the temperature sensor 64. Furthermore, in the upper part of the composite plating solution storage tank 36,
A hopper 72 for sending a pH adjusting agent, preferably nickel carbonate fine particles, to the composite plating solution 50 is provided, and a nickel carbonate metering device 74 faces the hopper 72.

The output signal of the pH sensor 66 is sent to the pH controller 76, and the composite plating solution 50 is supplied to the desired p
In order to control the H value, a predetermined signal is sent from the pH controller 76 to the nickel carbonate metering device 74.
The nickel carbonate metering device 74 weighs fine particles of nickel carbonate and mixes the composite plating solution 5 in the composite plating solution storage tank 36.
When the pH value of 0 is insufficient, the fine particles are put into the composite plating solution storage tank 36 from the hopper 72, and the motor 5
2 rotates the stirring blade 56 and operates so that the fine particles of nickel carbonate are uniformly melted in the composite plating solution 50 under the rotation of the stirring blade 56.

In this embodiment, the temperature controller 68 and the pH controller 76 independently adjust the temperature and pH value, but the temperature controller 68 and the pH controller 76 can also be controlled based on the correlation between the two. In this case, the temperature controller 68 and the pH controller 76 are connected to the CPU 78 (see the broken line in FIG. 1), and the CPU 78 has a table 80 shown in FIG. 2 therein. As is easily understood from FIG. 2, this table 80 defines the correlation between the temperature and the pH value of the composite plating solution 50.

The apparatus 10 for carrying out the composite plating method for a cylinder block according to the present embodiment is basically constructed as described above, and next, in relation to the composite plating method, The action and effect will be described.

The electrode rod 24 is electrically connected to the + side terminal of the DC power supply 26, and the cylinder W is electrically connected to the-side terminal of the DC power supply 26 via the conductor 30. At that time, the cylinder W is subjected to a plating pretreatment process in advance. In the present embodiment, the cylinder W is cast from, for example, the aluminum alloy AC2B or AC4B, because it is necessary to secure the adhesion between the aluminum material and the plating film by this plating pretreatment step. is there. In this embodiment, a double zinc displacement plating method is adopted as the plating pretreatment process.

On the other hand, the following consideration was given to the composite plating solution 50. That is, in order to remove the unevenness of the hardness (hardness) of the plating film, as described above, for example, nickel sulfate 400 per liter of water is used.
g, 35 g of boric acid and 55 g of silicon carbide fine particles are added, and 3 g of saccharin sodium is used as a brightening agent. This is because in consideration of the electrolysis conditions and the eutectoid property of silicon carbide, the sensitivity of pH and current density is reduced to suppress the variation in the film hardness of the plating layer.
These are the values obtained experimentally. On the other hand, the following improvements were made to improve the toughness (strength) of the composite plating layer. The parameters that affect the toughness of the composite plating layer are the temperature and pH value of the composite plating solution 50. Therefore,
In this embodiment, the temperature of the composite plating solution 50 was experimentally set in the range of about 45 ° C to 57 ° C, and the pH value was set in the range of 1.7 to 2.7.

After the preparation as described above, first, the cylinder W is placed and fixed on the first jig 14, and the slider 18 is lowered in FIG. The cylinder W is positioned and fixed between the above and the first jig 14. Next, the opening of the cylinder W is closed using the seal units 28a and 28b. In this case, the second
The electrode rod 24 fixed to the jig 22 enters into the hole portion formed in the cylinder W, and the tip end portion thereof has the first jig 14
While facing the tapered hole portion 32, a uniform and extremely minute gap S is defined between the inner peripheral surface of the hole portion of the cylinder W and the electrode rod 24.

Therefore, when the composite plating process is started, the temperature controller 68 energizes / deenergizes the heater 60 and the cooler 70 according to the temperature detected by the temperature sensor 64 to set the temperature of the composite plating solution 50 at the set temperature. 45 ° C ~ 5
The temperature is maintained at 7 ° C, preferably 50 ° C to 55 ° C. On the other hand, the composite plating solution 5 detected by the pH sensor 66
A pH value of 0 is controlled by the pH controller 76. That is, the pH value of the composite plating solution 50 is set to 1.
If necessary, nickel carbonate fine particles are charged into the composite plating solution 50 from the nickel carbonate metering device 74 through the hopper 72 so as to be 7 to 2.7, preferably 2. Then, while the motor 52 is driven to rotate the stirring blade 56, the temperature of the composite plating solution storage tank 36 is set such that the temperature is in the set range of 45 ° C. to 57 ° C. and the pH value is in the range of 1.7 to 2.7. The composite plating solution 50 inside is adjusted.

In the above-mentioned first embodiment, the temperature controller 68 and the pH controller 76 individually control the temperature and the pH value, but as described above, the second embodiment is used.
In the case of the embodiment, the CPU 78 can control the temperature controller 68 and the pH controller 76 in association with each other. For example, according to the table 80, when the temperature is 35 ° C., the CPU 78 sends a signal to the temperature controller 68 to energize the heater 60 to change the temperature of the composite plating solution 50 to 5 as indicated by a circle in the table 80.
Raise to around 5 ° C. On the other hand, when the temperature of the composite plating solution 50 reaches around 60 ° C., the CPU 78 controls the temperature controller 6 to prevent the composite plating layer from having high toughness.
8 is commanded to energize the cooler 70 to control the temperature of the composite plating solution 50 so as to be out of the high toughness region of the table 80. Similarly, for the pH controller 76, for example, when the pH value detected by the pH sensor 66 is less than about 1.7, fine particles of nickel carbonate are composite plated from the nickel carbonate metering device 74 through the hopper 72. Add to liquid 50. That is, according to this embodiment,
The temperature of the composite plating solution 50 is adjusted to the range of 45 ° C to 57 ° C, and the pH value is adjusted to the range of 1.7 to 2.7. Therefore, in the first embodiment, the temperature controller 68 and p
Each of the H controllers 76 can independently perform control so as to approach a preferable set value as much as possible. In the second embodiment, the CPU 78 is used to control the temperature of the composite plating solution 50 and It is possible to perform control in which the pH value is correlated. In FIG. 2, x indicates a burnt-out region, ▲ indicates that the plated layer is in a high toughness region, and Δ indicates that the eutectoid efficiency of the composite plated layer is 90% or less. Shows. In particular, the plating burned region and the high toughness region both exhibit defects in the present embodiment.

The composite plating solution 50 whose temperature and pH value have been adjusted through such preparation steps is fed to the cylinder W side under the action of the supply pump 38. At that time, the air compressor 46 is driven to supply fine air bubbles from the branch pipe 44 to the supply pipe 34, and the fine bubbles are mixed in the composite plating solution 50.

As described above, the electrode rod 24 is connected to the DC power source 26.
, And the cylinder W is connected to the-side terminal of the DC power supply 26, nickel and silicon carbide are co-deposited from the composite plating solution 50 to form a composite plating layer on the inner surface of the cylinder W. To be formed.

As the conditions of the plating process in this case, for example, the supply rate of the composite plating solution 50 is 15 cm / sec, and the amount of air supplied from the air compressor 46 through the branch pipe 44 having a diameter of about 70 mm is It was 7.5 liters per minute. By the way, during the experiment,
The diameter of the nozzle portion of the tapered hole 32 of the first jig 14 is 16 mm, the position of the nozzle is about 500 mm below the composite plating layer, and the diameter of the supply pipe 34 is about 40 mm. there were.

On the other hand, the test for coating toughness was carried out using a scratch tester, and as a result, the composite plating solution 50 was used.
It was found that the toughness of the coating film can be particularly reduced when the pH of the composite plating solution is 2 and the temperature of the composite plating solution 50 in the composite plating solution storage tank 36 is 50 ° C. This reduction in film toughness avoids the occurrence of cracks in the composite plating layer.

As shown in the table of FIG. 2, the pH value of the composite plating solution 50 is kept in the range of about 1.7 to 2.7, and the temperature of the composite plating solution 50 is suppressed to around 45 ° C. to 57 ° C. As a result, a particularly good composite plating layer can be obtained on the inner peripheral surface of the bore of the cylinder block.

[0034]

As described above, in the composite plating method for a cylinder block according to the present invention, when the composite plating layer is formed on the inner peripheral surface of the cylinder bore, the temperature control means and the pH control means are applied to the composite plating solution. It is used to adjust the temperature and pH value of the composite plating solution in association with each other. Therefore, the composite plating layer can be formed under extremely good conditions under the action of the temperature control means and the pH adjustment means. In particular, the p
The pH value of the composite plating solution is suppressed to, for example, 1.7 to 2.7, preferably around 2 by the H adjusting means, and the temperature of the composite plating solution is 45 ° C. to 57 ° C., preferably 50 ° C.
When determined in the vicinity, no plating burnt on the inner peripheral surface of the cylinder bore, without occurrence of cracks, yet with adequate toughness and composite plating layer excellent in codeposition efficiency.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view of an apparatus for carrying out a cylinder block composite plating method according to a preferred embodiment of the present invention.

FIG. 2 is a CP incorporated in the composite plating apparatus shown in FIG.
It is a table which defines the correlation between the pH value and the temperature of the composite plating solution in U.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Composite plating device 24 ... Electrode rod 26 ... DC power supply 34 ... Supply pipe 36 ... Composite plating solution storage tank 50 ... Composite plating solution 52 ... Motor 56 ... Stirring blade 60 ... Heater 62 ... Cooling tube 64 ... Temperature sensor 66 ... pH sensor 68 ... Temperature controller 70 ... Cooler 74 ... Nickel carbonate metering device 76 ... pH controller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Ishigami 1-10-1 Shin Sayama, Sayama City, Saitama Honda Engineering Co., Ltd. (56) Reference JP-A-5-222589 (JP, A) JP-A-8 -239793 (JP, A) JP-A-7-278898 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C25D 15/02

Claims (4)

(57) [Claims] 1. A method of forming a composite plating layer by inserting an electrode into a cylinder bore formed in a cylinder block and circulatingly supplying a composite plating solution to an inner peripheral surface of the cylinder bore, wherein the composite plating solution is a nickel sulfate solution. And a silicon carbide, wherein the composite plating solution has a temperature and a pH of the composite plating solution.
Of the formed plating, whether or not there is burnt-out, toughness, and
And a CP having a table in which the relationship with the eutectoid efficiency is entered
Under the control action of U, the plating formed is a plating burned area.
Out of the high toughness region and the eutectoid efficiency is 90% or less
After being adjusted so as to be out of the area,
The temperature is in the range of 45 ° C to 57 ° C and the pH is 1.7 to 2.7.
And the cylinder block is supplied to the cylinder block. 2. The method of composite plating of a cylinder block according to claim 1, wherein the composite plating solution is stored in a composite plating solution storage tank, and the temperature is adjusted to 45 ° C. by a temperature adjusting means arranged in the composite plating solution storage tank. A composite plating method for a cylinder block, wherein the temperature is controlled in the range of ˜57 ° C. 3. The composite plating method for a cylinder block according to claim 1 or 2, wherein the composite plating solution is stored in a composite plating solution storage tank, and the composite plating is performed by a pH adjusting means provided in the composite plating solution storage tank. A composite plating method for a cylinder block, wherein the pH value of the solution is adjusted to a range of 1.7 to 2.7. 4. The composite plating method for a cylinder block according to claim 3, wherein when the pH value of the composite plating solution is outside the set pH value range, fine particles of nickel carbonate are contained in the composite plating solution storage tank. A composite plating method for a cylinder block, which is characterized by being weighed and charged.