JPH03253577A - Surface treatment of aluminum cylinder block - Google Patents

Abstract

PURPOSE:To prevent trouble due to the temp. difference between cylinder bores by controlling the temp. of a washing soln. or a treating soln. for each of the bores in accordance with the temp. of each of the bores measured before filling the treating soln. CONSTITUTION:When the surfaces of the cylinder bores in an aluminum multicylinder block 25 are washed with a washing soln. and a treating soln. is filled to carry out chemical treatment, the temp. of each of the bores is measured with a thermometer 18 and the temp. of at least one of the washing soln. and the treating soln. for each of the bores is controlled in accordance with the measured temp. with a temp. controlling system 16. Equal amts. of silicon crystals can be protruded from the surfaces of the bores.

Description

Detailed Description of the Invention (Industrial Application Field) This invention provides an alternative to providing a cylinder bore in order to prevent pistons from seizing in the cylinder bore of a cylinder block made of an aluminum alloy containing silicon (Si). The present invention relates to a surface treatment method for an aluminum cylinder block, which is suitable for use when surface treatment is performed to expose silicon crystals on the surface of the bore portion through a chemical reaction.

(Prior art) Examples of conventional systems for performing such surface treatment include:
There is one shown in Figure 5.

The system comprises a pre-cleaning station 1, a surface treatment station 2 and a post-cleaning station 3, where the pre-cleaning and post-cleaning stations 1.3 are each provided with a cleaning liquid tank 4, 6. In addition, the surface treatment station 2 is provided with a treatment liquid tank 5.
Further, the tanks 4 to 6 are provided with mutually independent liquid temperature control systems 7 to 9.

In such a surface treatment system, the cylinder bore of an aluminum cylinder block as a workpiece processed in the pre-process 10, which is a machining process, is pre-cleaned with a cleaning liquid in a pre-cleaning station 1, and the surface is cleaned with a treatment liquid in a surface treatment station 2. A chemical treatment is applied to expose the silicon crystals,
Thereafter, a post-cleaning step is performed at a post-cleaning station 3, and the aluminum cylinder block after the surface treatment is inspected for the inner diameter of each cylinder bore portion, etc. in a post-process 11, which is an inspection process.

In the above system, each liquid temperature management system 7 to
No. 9 maintains and manages the liquid temperature in the tanks 4 to 6 of the corresponding stations to a level that does not cause problems in cleaning and surface treatment efficiency, regardless of the workpiece temperature.

(Problems to be Solved by the Invention) Surface treatment by chemical reaction is greatly influenced by the surface temperature of the object to be treated.

For example, Fig. 6 shows that a plurality of test pieces of the same quality as an aluminum cylinder block, which were at room temperature, were immersed for 30 seconds in processing solutions of different concentrations and liquid temperatures, and silicon crystals on the surface of each test piece were removed. (In this test, a NaOH aqueous solution was used as the treatment liquid, and in the figure, α is 10%, β is 35%, and γ is 60%.) As is clear, at any concentration, if the liquid temperature is varied and the surface temperature of the test piece is varied, a large difference will occur in the amount of protrusion.

Therefore, during surface treatment, it is necessary to raise the surface temperature of the cylinder bore of the aluminum cylinder block considerably higher than the outside air temperature in order to increase the treatment efficiency, so the temperature of the cleaning liquid at pre-cleaning station 1 is also quite high. Therefore, the cylinder bore is cooled in the atmosphere after cleaning at the pre-cleaning station 1 and before surface treatment with a treatment liquid at the surface treatment station 2.

However, when a cylinder block has multiple cylinders, the heat capacity usually differs between the bores, so for example, in the case of a four-cylinder block, the cylinder bores located at both ends are particularly easy to cool, and the cooling rate between the bores varies. different.

Therefore, even if the temperatures are equal between the bores at the end of pre-cleaning,
When starting surface treatment, a temperature difference occurs between the bores.

In addition, before entering the pre-cleaning station 1, the cylinder block has heat due to machining in the pre-process 10, and cooling between the pre-process and the pre-cleaning causes a similar phenomenon between the bore parts as described above. Temperature differences often occur.

Therefore, it is extremely difficult to obtain a uniform amount of silicon crystal protrusion between the bore portions during surface treatment.

The present invention provides a surface treatment method that advantageously solves these problems.

(Means for Solving the Problems) The method for surface treatment of an aluminum cylinder block of the present invention is as follows:
When chemically treating the surface of each cylinder bore of a multi-cylinder aluminum cylinder block by cleaning it with a cleaning liquid and filling it with a processing liquid, the temperature of each cylinder bore is measured after cleaning with the cleaning liquid and before filling it with the treatment liquid. The present invention is characterized in that the temperature of at least one of the cleaning liquid and the processing liquid is controlled for each cylinder bore portion based on this temperature.

(Function) According to this method, the liquid temperature of at least one of the cleaning liquid and the processing liquid is adjusted between each cylinder bore part based on the actual temperature difference obtained from the measurement results of the temperature of each cylinder bore part before filling with the processing liquid. Therefore, when controlling the liquid temperature of the cleaning liquid, the liquid temperature of the cleaning liquid supplied to the bore part where the cooling rate is high is increased, and the temperature between the bore parts is increased before filling with the processing liquid. If you want to eliminate the difference in surface temperature and control the temperature of the processing liquid, increase the temperature of the processing liquid supplied to the bore part where the cooling rate is fast, so that the temperature of the processing liquid increases during surface treatment. The temperature difference between the bore portions can be appropriately reduced, and therefore a uniform amount of silicon crystal protrusion can be obtained between the cylinder bore portions.

Furthermore, by controlling the liquid temperature of both the cleaning liquid and the processing liquid, the takt time at each station of the surface treatment system can be shortened.
Even if the temperature difference cannot be sufficiently eliminated with only one station, a uniform amount of silicon crystal protrusion can be obtained between each cylinder bore at the surface treatment station.

Furthermore, according to this method, the temperature difference between the bore parts is almost or completely eliminated during surface treatment, so there are no problems caused by the temperature difference between the bore parts in the post-cleaning process. For example, even when an inspection is performed in a post-process after post-cleaning, there is little or no measurement error due to temperature differences, and therefore measurement work can be made easier.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram illustrating a surface treatment system used in an embodiment of the aluminum cylinder block surface treatment method of the present invention, and in the figure, the same parts as the conventional system are designated by the same reference numerals. .

That is, the surface treatment system here includes a pre-cleaning station 1, a surface treatment station 12, and a post-cleaning station 13, where the pre-cleaning and post-cleaning stations 1 and 13 each have a cleaning liquid tank 4. , 15 are provided, and a surface treatment station 12
is provided with a processing liquid tank 14, and furthermore, these tanks 4 to 6 are provided with mutually independent liquid temperature control systems 7, 16, and 17.

Here, the surface treatment station 12 is also provided with a bore temperature measuring device 18 .

FIG. 2 shows the configuration of the surface treatment station 12, treatment liquid tank 14, liquid temperature management system 16, and bore temperature measurement device 18 in more detail. In order to correspond to the aluminum cylinder 25 of the cylinder, each cylinder bore section is equipped with four independent processing liquid supply nozzles 12a, and four pumps (not shown) each connected to these nozzles 12a via a pipe line. There is.

Further, the bore temperature measuring device 18 provided in the surface treatment station 12 includes two infrared radiation thermometers 18a. This infrared radiation thermometer was used because it has sufficient measurement accuracy and the measurement time is extremely short, making it possible to measure temperature without extending the takt time of the surface treatment system. Other temperature measurement means may be used as long as there are no problems in terms of accuracy and measurement time.

On the other hand, the processing liquid tank 14 has four processing liquid tanks 14a each storing a processing liquid 26 such as an NaOH aqueous solution, which are independent for each cylinder bore, in order to correspond to the in-line four-cylinder aluminum cylinder 25. Those processing liquid tanks 14
The treatment liquid suction nozzles 14b are respectively connected to the four pumps of the surface treatment station 12 via pipes.

The surface treatment system here employs a liquid circulation system in which the liquid used at each station is returned to each tank via a pipe (not shown) after removing foreign matter using a filter (not shown).

The liquid temperature management system 16 also controls the processing liquid tank 14.
There are four heating devices 16a, such as electric heaters, provided for each processing liquid tank 14a within the processing liquid tank 14.
It controls the operation of four liquid temperature sensors 16b, such as thermocouples, provided for each processing liquid suction nozzle 14b, and the two infrared radiation thermometers 18a, and also controls the operation of the two infrared radiation thermometers 18a. A control device 16 with a built-in microcomputer, for example, which manually controls the operation of the four heating devices 16a based on the output signal BT and the output signal LT of the four liquid temperature sensors 16b.
It is equipped with c.

Furthermore, in FIG. 1, the post-cleaning station 13 is also
The cleaning liquid tank 15 and liquid temperature management system 17 have an independent configuration for each cylinder bore similar to the surface treatment station 12, and the cleaning liquid tank 15 and liquid temperature management system 17 also have an independent configuration for each cylinder bore similar to the treatment liquid tank 14 and liquid temperature management system 16. The liquid temperature management system 17 also receives the output signals BT from the two infrared radiation thermometers 18a.

In this surface treatment system, each of the four cylinder bores of an in-line four-cylinder aluminum cylinder block as a workpiece processed in a pre-process 10, which is a machining process, is pre-cleaned with a cleaning liquid at a pre-cleaning station 1. ,
The surface treatment station 12 performs a chemical treatment to expose silicon crystals on the surface using a treatment solution, and then the post-cleaning station 13 performs post-cleaning.The aluminum cylinder block after the surface treatment is inspected in the inspection process. In a certain post-process 11, the inner diameter and the like of each cylinder bore are inspected.

Therefore, in the pre-cleaning with the cleaning liquid at the pre-cleaning station l, the cleaning liquid in one cleaning liquid tank 4, which is maintained at a liquid temperature described later by the liquid temperature management system 7 which is higher than room temperature, is applied to all the bore parts. As a result, as shown in FIG. 2, the aluminum cylinder block 25 that has been pre-cleaned and delivered to the surface treatment station 12 has no pre-machining process. Cooling before cleaning and cooling between pre-cleaning and surface treatment create a temperature difference between cylinder bores.

In order to eliminate the influence of this temperature difference between the bore parts on the chemical processing, in the surface treatment station 12, before filling the processing liquid, the two control devices 16c are first activated by a start signal indicating the loading of the aluminum cylinder block 25. The infrared radiation thermometer 18a measures the temperature of each cylinder bore of the cylinder block 25, and its output signal BT is input.

Here, each infrared radiation thermometer 18a is arranged so that three cylinder bores fit within the measurement screen, and the output signal BT of the infrared radiation thermometer 18a indicates the temperature distribution within the measurement screen. ing. For this reason, the control device 16c
Image processing is performed to create a window at a position corresponding to the bore in the measurement screen, and the temperature particularly near the surface of each bore is determined.

Therefore, the number of infrared radiation thermometers 18a can be changed as appropriate depending on the type of aluminum cylinder block, the number of cylinders, required temperature measurement accuracy, etc.

Then, the control device 16c determines the substantial surface temperature difference between the respective bore portions immediately before surface treatment from the measured temperature near the surface of each bore portion, and based on the temperature difference, performs the following in each treatment liquid tank 14a. The corresponding heating device 16a is activated.

In other words, when a processing liquid with a liquid temperature higher than the reference temperature is filled into the bore of a multi-cylinder cylinder block whose surface temperature is lower than a certain predetermined reference temperature, the surface temperature of the bore becomes equal to the reference temperature immediately after filling. After the temperature of the processing liquid exceeds the temperature and once rises to near the initial temperature of the processing liquid, the temperature of the processing liquid inside the bore decreases due to heat conduction to the peripheral portion of the bore. On the other hand, even if a processing liquid with a liquid temperature equal to the reference temperature is filled into another bore whose initial surface temperature is equal to the reference temperature, there is almost no heat conduction to the surrounding areas of the bore. Both the surface temperature and the processing liquid temperature hardly change.

Therefore, for bores whose initial surface temperature is lower than the reference temperature, based on the relationship between the processing liquid temperature and the amount of silicon crystal protrusion mentioned above, the surface temperature of the bore at the end of the treatment will be slightly lower than the reference temperature. If the initial treatment liquid temperature is set higher than the reference temperature and set appropriately, the surface temperature of the bore will change from the start to the end of the process, and the chemical reaction rate will change, but the process will not end. The amount of protrusion of the silicon crystal on the surface of the bore portion at this time is substantially equal to the amount of protrusion of the silicon crystal at the end of the treatment in the bore portion where the initial surface temperature is equal to the reference temperature.

Figure 3 shows the results of measuring the surface temperature distribution of the bore area after pre-cleaning an actual in-line four-cylinder aluminum cylinder block using a conventional surface treatment system in the same manner as in this example. As shown by solid line A, the outer first and fourth cylinders are smaller than the inner second and third cylinders.
The cylinder will be lower. Among the bores having such a temperature difference, the liquid temperature of the processing liquid supplied to the bores of the second and third cylinders and the liquid temperature of the processing liquid supplied to the bores of the first and fourth cylinders, As shown by the dashed line B in the figure, as a result of applying a temperature difference that increases the temperature of the latter liquid and filling each bore with these treatment liquids to perform surface treatment, the protrusion amount of silicon crystals is actually the same between each bore. was gotten.

Based on this theory, in this surface treatment system, the reference temperature is set to a liquid temperature that improves the efficiency of surface treatment, and the inside of the aluminum cylinder block 25, which has been carried into the surface treatment station 12 after pre-cleaning, is The second. The liquid temperature control system 7 of the pre-cleaning station l adjusts the liquid temperature of the cleaning liquid so that the surface temperature of the bore of the third cylinder becomes the reference temperature as shown by the solid line in FIG. The control device 16c corresponding to the processing station 12 sets the liquid temperature of the processing liquid supplied to the second and third cylinders respectively to the reference temperature as shown by the chain line B in FIG. The heating device 16a corresponding to each processing liquid tank 14a is operated to increase the temperature of the processing liquid supplied to each of the four cylinders from the reference temperature based on the measured temperature difference. The temperature of the processing liquid inside is adjusted.

The relationship between the temperature difference between the cylinder bores before the start of processing and the temperature of the processing liquid supplied to each bore at which the protrusion amount of silicon crystals at the end of the processing can be made equal to each other depends on the type of cylinder block and the temperature of the processing liquid supplied to each bore. Since the heat capacity distribution differs depending on the type, etc., it will change, so it is necessary to measure and find it in advance for each type and type of cylinder block, etc. In this system, we also measure the four cylinders mentioned above in advance and perform the above control. The information is stored in the device 16c.

As described above, according to this surface treatment system, it is possible to obtain a uniform amount of silicon crystal protrusion between each cylinder bore, and also to almost eliminate the temperature difference between each cylinder bore at the end of the surface treatment. I can do it.

In this surface treatment system, furthermore, in the surface treatment station 12, after the surface treatment is finished, the control device 16c once again causes the two infrared radiation thermometers 18a to measure the temperature of each cylinder bore of the cylinder block 25. The output signal BT is inputted to a control device of the liquid temperature management system 17 corresponding to the post-cleaning station 13, which has a configuration similar to the above-mentioned control device 16c.

The liquid temperature management system 17 is configured in the same manner as the liquid temperature management system 16 in the surface treatment station 12, taking into account cooling from the end of surface treatment to post-cleaning and cooling from post-cleaning to post-processing. , the first, where the temperature tends to drop. The liquid temperature of the cleaning liquid supplied to the bore of the fourth cylinder is set to 2. The temperature of the cleaning liquid in each cleaning liquid tank of the cleaning liquid tank 15 is adjusted so as to be higher than the temperature of the cleaning liquid supplied to the bore of the third cylinder.

Therefore, according to this surface treatment system, it is possible to eliminate the temperature difference between the cylinder bore parts even when inspecting in the post-process 11, and it is possible to avoid the occurrence of measurement errors between the bore parts due to the temperature difference. , measurement work can be made extremely easy.

In addition, the processing liquid tank 14 and the cleaning liquid tank 15 are arranged in such a way that the required liquid temperature can be adjusted within the takt time per workpiece at each station in the surface treatment system.
Since it is practically inefficient to set the amount of liquid in the processing liquid tank 14 or the cleaning liquid tank 15 and the heating capacity of the heating device, it is necessary to set a certain amount of liquid in the processing liquid tank 14 and the cleaning liquid tank 15 and the heating capacity of the heating device. Same as before, when the surface treatment system starts operating, the liquid temperature corresponding to each bore part in the processing liquid tank 14 and cleaning liquid tank 15 is adjusted based on the temperature difference between the cylinder bore parts measured in advance.
After the surface treatment system starts operating, control is performed to stabilize conditions over a certain period of time based on the temperature difference measured in the cylinder block flowing through it.

FIG. 4 is a diagram illustrating a structure of a surface treatment system used in another embodiment of the present invention; in the figure, parts that are the same as those of the conventional example or the previous embodiment are designated by the same reference numerals.

That is, in this surface treatment system, the pre-cleaning station 19 and the post-cleaning station 20 are provided with independent cleaning fluid supply and discharge paths for each cylinder bore, similar to the surface treatment station 12 in the previous embodiment, and these cleaning stations 19 Cleaning liquid tank 21. corresponding to .20.
22, each cylinder bore has an independent cleaning liquid tank similar to the treatment liquid tank 14 used in the surface treatment station 12 in the previous embodiment, and these cleaning liquid tanks 2
Liquid temperature management system corresponding to 1.22 respectively 23.24
However, similar to the liquid temperature management system 16 used in the surface treatment station I2 in the previous embodiment, it includes a heating device and a control device for separately adjusting the liquid temperature of the cleaning liquid in each cleaning liquid tank.

Also, here, surface treatment stage 2 similar to the conventional example is used.
A bore temperature measuring device 18 similar to that used in the surface treatment station 12 in the previous embodiment is provided, and the output signal BT of this bore temperature measuring device 18 is applied to both cleaning stations 19 and 20, respectively. Liquid temperature management system 2
3.24, a control device having the same configuration as the control device 16c in the previous embodiment inputs.

In this surface treatment system, as in the previous embodiment, the surface of each cylinder bore portion of an aluminum cylinder block as a workpiece processed in the pre-process 10, which is a machining process, is subjected to pre-cleaning and chemical treatment to expose silicon crystals. Processing and post-cleaning are performed, and the aluminum cylinder block after surface treatment is inspected in post-process 11.

However, in the surface treatment station 2, before filling the processing liquid into each cylinder bore of the aluminum cylinder block, the bore temperature measurement device 18 measures the temperature of each cylinder bore, and outputs the measurement result. Based on BT, the control device of the liquid temperature management system 23 corresponding to the pre-cleaning station 19 takes into account the cooling between the machining process and the pre-cleaning, and the cooling between the pre-cleaning and the surface treatment. Surface treatment station 12 according to an embodiment of
In the same manner as the liquid temperature management system 16 in the pre-cleaning station 19, the liquid temperature of the cleaning liquid supplied to each cylinder bore part is controlled in the first station where the temperature tends to decrease. Regarding the bore part of the fourth cylinder, see the second section. The liquid temperature of the cleaning liquid in each cleaning liquid tank of the cleaning liquid tank 21 is adjusted so as to be higher than that in the bore of the third cylinder.

Therefore, according to this surface treatment system, it is possible to substantially eliminate the temperature difference between the cylinder bores before the start of surface treatment in the surface treatment station 2, and it is possible to obtain a uniform protrusion amount of silicon crystal between each cylinder bore. At the same time, the temperature difference between the cylinder bores at the end of the surface treatment can also be almost eliminated.

In this surface treatment system, furthermore, in the surface treatment station 2, after the surface treatment is finished, the bore temperature measuring device 18 measures the temperature of each cylinder bore once again, and based on the output signal BT of the measurement result, the post-cleaning station The control device of the liquid temperature management system 24 corresponding to the liquid temperature control system 20 controls the liquid temperature at the pre-cleaning station 19, taking into account cooling between the end of surface treatment and post-cleaning, and cooling between post-cleaning and post-processing. Similarly to the management system 23, the liquid temperature of the cleaning liquid supplied to each cylinder bore in the post-cleaning station 20 is adjusted such that the temperature of the cleaning liquid supplied to each cylinder bore is adjusted such that the temperature of the cleaning liquid supplied to the bore of the first and fourth cylinders, where the temperature tends to drop, is adjusted to the second. The liquid temperature of the cleaning liquid in each cleaning liquid tank of the cleaning liquid tank 22 is adjusted so as to be higher than that in the bore of the third cylinder.

Therefore, according to this surface treatment system, it is possible to eliminate the temperature difference between the cylinder bore parts even when inspecting in the post-process 11, and it is possible to avoid the occurrence of measurement errors between the bore parts due to the temperature difference. , measurement work can be made extremely easy.

Although the above has been explained based on the illustrated example, the present invention is not limited to the above-mentioned machine. For example, the takt time per workpiece at each station in a surface treatment system is short, and if only one station If the temperature difference between the parts cannot be sufficiently eliminated, the liquid temperature of both the cleaning liquid in the pre-cleaning station and the processing liquid in the surface treatment station may be controlled.
In the surface treatment station, it is possible to obtain a sufficiently uniform protrusion amount of silicon crystal between the cylinder bores, and also to sufficiently eliminate the temperature difference between the cylinder bores at the end of the surface treatment.

In addition, the above-mentioned bore temperature measurement device is installed in the pre-cleaning station to measure the temperature difference between the cylinder bores immediately after pre-cleaning, and from the measurement results, it is possible to determine whether the cooling between the machining process and pre-cleaning is The temperature of at least one of the cleaning liquid and the processing liquid may be controlled for each cylinder bore in consideration of cooling up to the surface treatment, and such a method can also achieve the same effects as the above-mentioned embodiment. can bring.

(Effects of the Invention) Thus, according to the surface treatment method of the present invention, it is possible to obtain a uniform amount of protrusion of silicon crystals between each cylinder bore, and to reduce the amount of silicon crystals that are caused by temperature differences between the bores in the post-cleaning process. It is possible to prevent such problems from occurring.

[Brief explanation of drawings]

Figure 1 is a configuration diagram illustrating a surface treatment system used in an embodiment of the surface treatment method for aluminum cylinder blocks of the present invention, and Figure 2 is a surface treatment station, treatment liquid tank, and liquid temperature control system in the above surface treatment system. and a configuration diagram showing further details of the bore temperature measuring device. Figure 3 shows the measurement results of the cylinder bore surface temperature distribution state of an actual four-cylinder aluminum cylinder block after pre-cleaning and before surface treatment, and the results in that case. FIG. 4 is a configuration diagram illustrating a surface treatment system used in another embodiment of the present invention, and FIG. 5 is a characteristic diagram showing an example of controlling the processing liquid temperature for each bore section. FIG. 6 is a diagram showing the configuration of the surface treatment system. FIG. 6 is a relationship diagram showing the results of a test on the relationship between the temperature and concentration of the treatment liquid and the protrusion amount of silicon crystals. 1.19...Pre-cleaning station 2.12...Surface treatment station 4, 15.21.22...Cleaning liquid tank 5.14...
・Processing liquid tank 7, 8.16.17.23.24...Liquid temperature management system 10...Pre-process 11...Post-process 1
3, 20...Post-cleaning station 18...Bore temperature measuring device 25...Aluminum cylinder

Claims (1)

[Claims] 1. When chemically treating the surface of each cylinder bore of a multi-cylinder aluminum cylinder block by cleaning it with a cleaning liquid and filling it with a treatment liquid, the temperature of each cylinder bore is measured after cleaning with the cleaning liquid and before filling it with the treatment liquid. A method for surface treatment of an aluminum cylinder block, characterized in that the temperature of at least one of a cleaning liquid and a treatment liquid is controlled for each cylinder bore portion based on this temperature.