JPH0124862B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to improving the wear resistance of sliding contact members used, for example, in engine cylinder liners, and
The present invention relates to an efficient method for manufacturing this sliding contact member with excellent wear resistance. [Prior Art] Conventionally, in an engine, a piston slides within a cylinder block, and a cylinder liner is fixed to the cylinder block as a sliding member having a sliding surface that contacts the piston. Therefore, this cylinder liner must have high wear resistance. To improve this wear resistance,
An appropriate amount of lubricating oil may be retained on the sliding surface, and this retained lubricating oil enhances the lubrication effect and improves wear resistance. In order to retain the lubricating oil on the sliding surface, there is a method of forming an oil retaining recess for retaining the lubricating oil on the sliding surface. By the way, the oil retention function of the oil retention recess increases as the area ratio of the recess increases, that is, the value obtained by dividing the total opening area of all oil retention recesses by the area of the entire sliding surface, but this oil retention ability is ensured. If the area ratio is increased in order to achieve this, the area of the plateau portion that makes sliding contact with the piston under high pressure will become smaller, which will increase the surface pressure per unit area, which is not preferable from the viewpoint of improving wear resistance. On the other hand, in order to increase the oil holding capacity without increasing the area ratio too much, the depth of the oil holding recesses can be increased. In the conventional forming method, if the amount of reverse electrolysis is increased in order to deepen the recesses, electrolysis is also promoted in the plateau areas between the recesses, resulting in a problem that the surface roughness thereof deteriorates. Therefore, the applicant of the present application has filed an application for a sliding contact member in which deep oil retaining recesses are regularly formed on the sliding surface using the photo etching method as a sliding contact member that can solve the above-mentioned conventional problems. 58−
111200), according to this prior art, a deep oil holding recess can be formed without deteriorating the surface roughness of the plateau portion, and the oil holding capacity can be improved without increasing the area ratio, and the durability is improved. Abrasion resistance can be improved. By the way, since the lubricating oil that is supplied and held in the oil holding recess is simply collected in this recess, it tends to be dragged away by the piston as it slides. In particular, as the sliding speed of the piston increases, the amount of oil carried away increases. Therefore, even in the case where the deep oil retaining recess is formed, the oil retaining ability may be insufficient depending on the sliding speed. [Object of the Invention] Therefore, the object of the present invention is to provide a sliding contact member that has a high oil retention ability that can provide sufficient lubrication effect even at high sliding speeds, and can greatly improve wear resistance. It is an object of the present invention to provide a method for manufacturing a sliding contact member that can efficiently obtain a sliding contact member having a high oil holding capacity through a simple process. [Structure of the Invention] The present invention involves forming a large number of recesses on a metal member having a sliding surface by a photoetching method, and then thermally spraying a thermal spraying material while leaving a resist film for photoetching on the metal member. Then, the resist film and the sprayed layer on the resist film are removed to obtain a sliding contact member in which a porous sprayed layer having a lubricant retaining function is formed only in the recess. As a method for forming recesses in a metal member having a sliding surface, for example a chrome plating layer, and forming a porous sprayed layer of molybdenum, for example, which has a lubricating oil retaining function in the recesses, as mentioned above, the photo etching method is used. It is known that a method of forming a recessed portion is made using the following method, and it is also known that a thermally sprayed layer of Mo or the like has excellent scuffing resistance. Therefore, the following method can be considered. That is, the method involves etching recesses in the Cr plating layer by photoetching, removing the photoetching resist film, and then plasma spraying Mo on the plating layer, for example. However, a processing method that simply combines the above-mentioned photoetching method and plasma spraying may cause the following problems. There is a strong oxide film on the Cr plating layer, and the Cr plating layer also has poor wettability for sprayed particles, so the sprayed particles do not attach to the surface of this plating layer but scatter around. These scattered particles inhibit thermal spraying into the recesses, making it difficult to form a sprayed layer within the recesses. Furthermore, when thermal spraying is applied to the recesses, as mentioned above, the sprayed particles also collide with the Cr plating layer, but these colliding particles cause surface roughness of the Cr plating layer itself, and as a result, the wear resistance cannot be improved that much. . Therefore, the present invention provides a method for manufacturing a sliding contact member having excellent wear resistance as described above.
After forming a large number of recesses by photoetching on a metal member consisting of the hard plating layer having a sliding surface and a metal base material, thermal spraying will not be possible if this photoetching resist film is left on the metal member. The material is thermally sprayed, and then the resist film and the thermally sprayed layer formed on the resist film are removed.As a result, in the method of the present invention, the resist film remaining on the metal member is soft. Because of this, the sprayed particles easily adhere to this resist film, so the sliding surface of the metal member will not be roughened by the sprayed particles, and the sprayed particles will not scatter onto the metal member. Therefore, the sprayed particles will not be obstructed from entering the recesses by these scattered particles. Furthermore, unnecessary thermal sprayed layers on the resist film can be easily removed by removing the resist film. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the inner surface of a sliding member, such as a cylinder liner, according to an embodiment of the present invention. A plating layer, for example, a Cr plating layer 2 is formed, and this Cr plating layer 2
The outer surface of the piston serves as a sliding surface 2a that comes into sliding contact with a piston, which is a sliding member (not shown). and this
On the sliding contact surface 2a of the Cr plating layer 2, a large number of oil holding recesses 2b are formed by photoetching over the entire surface of the sliding contact surface 2a at equal pitches vertically and horizontally. It has a substantially U-shaped longitudinal section with a circular opening in plan view, and the portion of the sliding surface 2a where the recess 2b is not formed forms a plateau portion that comes into contact with the piston. A sprayed layer 3 formed by plasma spraying Mo, for example, is formed in each of the oil retaining recesses 2b, and its outer surface is approximately flush with the sliding surface 2a. Layer 3 is porous and has the function of reliably retaining lubricating oil. In the sliding contact member of this embodiment, the oil holding recess 2b
Since the thermal sprayed layer 3 inside is porous, the lubricating oil is reliably retained within this thermal sprayed layer 3 even when the sliding speed of the sliding member, in this case the piston, increases, thereby maintaining the lubrication effect. It can be obtained over a long period of time, and the properties of the thermal sprayed layer 3 itself can be utilized, so that the wear resistance can be greatly improved. In addition, as mentioned above, the spray particles sprayed on the flat part of the Cr plating layer 2 are scattered around and are difficult to adhere to the flat part, but in this example, the sprayed particles were not sprayed on the flat part but inside the recessed part. Since the sprayed layer is formed on the surface, the sprayed particles do not scatter and easily and reliably adhere to the inner surface of the oil holding recess 2b, and the adhesion between the sprayed layer 3 and the Cr plating layer 2 can be improved. . Next, a test for confirming the effect of improving the wear resistance of the sliding member of the above example will be explained. In this test, the degree of damage and seizure resistance of the sliding contact surface is tested, and the wear resistance is evaluated based on this. FIG. 2 shows a rotary abrasion tester for testing the abrasion resistance of the above examples by a pin-disk abrasion test method. In the figure, reference numeral 11 denotes a disk rotating section.A disk rotating shaft 12 is connected to a motor (not shown) of this section, and a disk 13, which is a test piece, is attached to this rotating shaft 12, so that the disk 13 is rotated in a predetermined position. It is designed so that it can be rotated at a rotation speed of . Reference numeral 14 denotes a disk pressing portion, and the tip of the support arm 15a, which is swingably attached to the support member 15, is provided with the disk 1.
A pin 16 for sliding on the sliding surface of 3 is attached, and a hanging rope 17 is connected to the rear end, this hanging rope 17 is wound around a guide pulley 18, and a load 19 is suspended at the lower end of As a result, the pin 16 is pressed against the sliding surface of the disk 13 even with a pressing load P. The base material of the disk 13 is made of alloyed cast iron, and a hard Cr plating layer (thickness 50μ, Vickers hardness 900 to 1000) is formed on the surface, and then #1000
It has been given a honing finish. In the test piece of this example, an oil holding recess was formed in the disk 13 by photoetching, and a molybdenum sprayed layer (approximately 20 μm in thickness) was formed in the recess. In Comparative Example 2, only the oil retaining recesses were formed on disk 13 by the photo-etching method.
is used as is. Also, the above pin 16
1 is a rectangular planar plate made by chilling alloyed cast iron having the chemical components shown in Table 1, and its sliding surface with the disk 13 has been processed as follows. A. Polishing finish Whetstone: GC#60 Sharpness: 1.6a Short blast finish Short: Carborundum #20 Sharpness: 10~40μ

[Table] First, to explain the degree of damage test on the sliding contact surface, this test is not based on lubricating oil, but on the effect of improving wear resistance due to the sprayed layer formed in the oil holding recess. Test conditions Pressure load: P = 4.5Kg Disk peripheral speed: 5m/sec Test time: 10 minutes Lubrication conditions: No lubrication Test results

[Table] As is clear from this test result (Table 2 above), in Comparative Example 2, in which only a chrome plating layer was formed on the base material, the degree of damage to the surface of the disk 13 was large, and the amount of wear on the pin 16 was large. However, in Comparative Example 1 in which recesses were formed in the chrome plating layer by photo-etching, both the degree of damage to the surface of the disk 13 and the amount of wear on the pin 16 were significantly reduced. In this example, the degree of damage on the surface of the disk 13 is even smaller, and the amount of wear on the pin 16 is lower than that in Comparative Example 1.
It can be seen that the wear resistance has been greatly improved by the molybdenum sprayed layer itself. Next, the seizure resistance test will be explained. This test tests the effect of improving the oil retention function by the molybdenum sprayed layer formed in the oil retention recess. Test conditions Pressure load: P = 4.5Kg Disk peripheral speed: 5m/sec Lubrication conditions: Oil (10W40) and kerosene
Drop 1 c.c. of lubricating oil mixed at 9 (Vol ratio). Test results

[Table] As is clear from the test results (Table 3),
The test piece of this example took longer to seize than Comparative Example 1, which indicates that the oil retention function was improved by the molybdenum sprayed layer. FIG. 3 shows a process diagram of a method for manufacturing a sliding contact member according to an embodiment of the present invention, and the method of this embodiment mainly consists of two steps: forming an oil retaining recess by photo etching, and forming a thermal spray layer by plasma spraying. Consisting of () First, a hard chrome plating layer 2 is formed on the surface of a base material 1 made of alloyed cast iron, and the surface of the plating layer 2 is smoothed by polishing or honing to form a sliding surface 2a. () Next, after degreasing the sliding contact surface 2a, a UV-sensitive photoresist is applied to the sliding contact surface 2a.
A previously prepared photomask (not shown) is placed on the photoresist film 4 in close contact with the photoresist film 4. This photomask is a film-like product obtained by creating an enlarged original drawing of the oil holding recess 2b and reducing it by photographing, and the portion corresponding to the oil holding recess 2b is a non-transparent portion. () When the above-mentioned photomask is mounted and irradiated with ultraviolet rays from a high-pressure mercury furnace (not shown), the portions of the above-mentioned resist film 4 that have been irradiated with ultraviolet rays are cured by exposure, and the non-transparent portions of the above-mentioned photomask are cured. The portions that were not irradiated with the ultraviolet rays due to obstruction, that is, the portions corresponding to the oil holding recesses 2b, were not cured, and the photomask was then removed and the resist film 4 was developed with a solution for unexposed areas made of trichloroethane. The uncured portion is dissolved and peeled off, and as a result, the resist film 4
An opening 4 is provided in a portion corresponding to the oil holding recess 2b.
a is formed and this opening 4 in the chrome plating layer 2
Part a will be exposed to the outside. () Then, when the chrome plating layer 2 on which the resist film 4 is formed is etched, the exposed portions are dissolved and a large number of oil holding recesses 2b are formed in the chrome plating layer 2 (the third
(see figure a). () Next, without removing the resist film 4, molybdenum spray particles are projected from the plasma spray nozzle 5 toward the resist film 4 and the oil holding recess 2b. Then, since the resist film 4 is much softer than the chrome plating layer, the sprayed particles on the resist film 4 easily adhere to the resist film 4 without scattering to the surroundings, and the oil retention recesses 2b
Since there are no scattered particles as described above, the sprayed particles are easily and reliably stacked in the recess 2b (see FIGS. 3b and 3c). () Finally, when the sliding contact member is immersed in a resist film solution made of methylene chloride, the resist film 4 is removed, and along with this, the sprayed layer 3a on the resist film 4 is also removed, thereby retaining the oil. A sliding contact member is obtained in which a porous molybdenum sprayed layer 3 having a lubricating oil retaining function is formed only in the recess 2b (see FIG. 3d). In this example, since molybdenum thermal spraying was carried out with the ultraviolet-cured resist film 4 remaining after photo-etching, the spray particles on this resist film 4 adhered to the film and were scattered around. However, the spraying into the oil retaining recess 2b is not hindered by the flying particles, and as a result, the sprayed layer 3 can be easily and reliably formed within the oil retaining recess 2b. Normally, when thermal spray particles collide with an organic film such as a resist film, the film is thought to melt due to the heat, but a resist film cured by ultraviolet rays has high heat resistance and is soft. Therefore, it is thought that the thermal spray particles easily adhere to the resist film without dissolving the resist film. Conversely, the surface of the chrome plating layer 2 is protected by the resist film 4, so the surface of the chrome plating layer 2 does not become rough, and the thermal sprayed layer on the resist film 4 The resist film 4 can be easily removed by simply immersing it in the same film stripping agent as in the past. Next, a comparative test for explaining the effects of the method of this example will be explained. This comparative test was conducted to demonstrate that the resist film 4 improves the efficiency of thermal spraying into the oil retaining recess 2b.In Comparative Example 1, the resist film 4 was removed after photo-etching and the thermal spraying work was carried out. In Comparative Example 2, the resist film 4 was removed after photo-etching, and the surface of the chromium plating layer 2 was subjected to blasting treatment to prevent the spray particles from scattering, and then thermal spraying was performed. Test conditions (1) Photo etching conditions Photoresist: Film type (resist layer thickness 15μ, resolution 30μ) Photomask: Halftone type (dot diameter 100μ,
(area ratio 10%) Developer: 111 trichloroethane Etching solution: CrO ₃ (250g/) at 30℃
Solution with H ₂ SO ₄ (2.5g/) (2) Thermal spraying conditions Thermal spraying material: Mo for thermal spraying (particle size 10-44μ) Thermal spraying type: Plasma spraying Output: 35KW Distance: 100m/m Number of thermal sprays: 10 passes (3) Resist film stripper after thermal spraying: methylene chloride test results

〔Effect of the invention〕

As described above, according to the method for manufacturing a sliding contact member according to the present invention, after forming a recessed portion by photoetching on a metal member having a sliding contact surface, a thermal spraying material is sprayed with a resist film remaining. So,
By using a simple structure in which the resist film used for photoetching is used as is, this resist film prevents the sprayed particles from scattering and protects the sliding surface from the collision of the sprayed particles. can be formed efficiently, and also has the effect of preventing the occurrence of surface roughness on the sliding surface.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a sliding contact member according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a test device thereof,
FIGS. 3a to 3d are process diagrams for explaining a method according to an embodiment of the present invention. 1...Metal base material, 2...Hard plating layer, 2a...
...Sliding surface, 2b...Oil holding recess, 3...Thermal spray layer, 3a...Thermal spray layer on the resist film, 4...Resist film.

Claims (1)

[Claims] 1. After forming a large number of recesses by photoetching on a metal member having a sliding surface, a thermal spraying material is sprayed with a resist film for photoetching remaining on the metal member, and then the resist film and the resist are thermally sprayed. A method for manufacturing a sliding contact member with excellent wear resistance, characterized by removing the thermal sprayed layer on the film and obtaining a sliding contact member in which a porous sprayed layer having a lubricant retaining function is formed only in the recesses. .