JPH0641722A - Sliding member and its production - Google Patents

Abstract

PURPOSE:To improve a sliding characteristic by forming the surface of a hard film as a hard film having fine ruggedness of specific surface roughness. CONSTITUTION:The hard film 2 is formed by vapor deposition on the surface of a sliding member 1a. The surface of the hard film 2 is formed as the surface having the fine ruggedness of 0.5 to 1.0mum in the designation of the surface roughness Rz. The surface of the hard film is subjected to working by which the fine ruggedness of 0.5 to 1.0mum in the designation of the surface roughness Rz is formed. As a result, the wear resistance and seizure resistance are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding member and a method for manufacturing the same, and for example, a sliding mode of reciprocating movement and a situation where a high surface pressure is generated makes it difficult to supply lubricating oil to the sliding surface. The present invention relates to a sliding member suitable for use in a sliding mode, and more specifically, it is used for a rocker arm that transmits the rotational movement of a camshaft to an intake / exhaust valve in a valve operating mechanism of an automobile engine. Is possible, and also
In a variable capacity type swash plate type compressor used as a compressor for an air conditioner mounted on a vehicle, it can be used as a sliding member such as a slider used for preventing rotation of a swash plate that causes reciprocal sliding. The present invention relates to a moving member and a sliding member manufacturing method suitable for manufacturing the sliding member.

[0002]

2. Description of the Related Art For example, reciprocal sliding occurs or is high like a rocker arm used in a valve operating mechanism of an automobile engine or a slider used in a variable displacement type swash plate compressor. In a sliding member that generates surface pressure, it is natural from the viewpoint of application that it is required to have excellent seizure resistance and wear resistance.

In general, in this type of sliding member, seizure often occurs immediately when a combination of metals of the same kind is used, and therefore, different metals are often used in combination, and steel and cast iron have been conventionally used. , Aluminum alloys, or sintered alloys are often used in combination.
Further, a wide range of research has been conducted to further improve sliding characteristics by subjecting the sliding surfaces of these sliding members to surface treatment.

By the way, in recent automobiles, the living space tends to be large without sacrificing the trunk space for the vehicle size, and the engine room is inevitably being miniaturized.

Along with this, it is necessary to reduce the size of the engine itself and other accessories, and there is a strong demand for maintaining the performance by increasing the rotation speed of the engine and each accessory. At the same time, there is a strong demand for improvement in fuel consumption, and miniaturization of moving parts is required in order to minimize the power loss consumed by sliding between the respective parts.

[0006] To give an example of such a demand for miniaturization,
There is a rocker arm, which is one of the components that make up the valve mechanism of an engine, and a compressor for air conditioning, which is one of the accessories. In this way, as a result of the miniaturization of moving parts,
The sliding portion is inevitably required to be downsized, and a smaller sliding area is required to receive a load similar to or larger than that in the conventional case. Further, due to the higher rotation speed, it becomes more difficult to supply lubricating oil to the sliding portion, wear and seizure of the sliding member are likely to occur, and there is a tendency to be exposed to more severe sliding conditions. .

As shown in FIG. 6, a rocker arm 11 which constitutes a valve operating mechanism of an engine is generally positioned by a rocker shaft 12 arranged on an engine head, and a camshaft 13 by a power transmission mechanism (not shown).
The rocker arm 11 swings along the shape of the cam 13a with the rocker shaft 12 as a fulcrum as a result of the rotation of the cam 13a, and the upper surface axial end of the intake / exhaust valve 14 located on the opposite side of the rocker shaft 12 from the cam 13a. Push down.

Since the repulsive force of the spring 17 acts on the intake / exhaust valve 14 via the retainer 15 and the cotter 16, the rocker arm 11 always slides along the profile of the cam 13a, and the sliding direction is as follows. It comes to reciprocate.

As a result, the rotational movement of the camshaft 13 synchronized with the engine speed is transmitted to the intake / exhaust valve 14.
The combustion chamber (not shown) is closed and the combustion chamber for intake and exhaust is opened. As the engine speed increases, the rocker arm 11, intake / exhaust valve 14, retainer 1
5, the inertial force of the entire valve mechanism components such as the cotter 16 becomes large, so that the repulsive force by the spring 17 becomes insufficient, and the rocker arm 11 cannot always follow the profile of the cam 13a. To move.

Therefore, in order to prevent such a situation, the spring 17 is strengthened, so that a larger surface pressure is applied to the sliding surface between the cam 13a and the rocker arm 11, and the sliding condition is It tends to be more severe.

Further, as described above, even with respect to the rocker arm 11 which is always exposed to severe sliding conditions at present, as the engine head itself is miniaturized, each component is also miniaturized, and further Due to the higher engine speed associated with the higher performance, it is required to withstand even higher surface pressure and high speed sliding in a smaller sliding area.

Furthermore, the auxiliary machinery in the engine room is strongly reduced in size and weight, and the compressor used in the vehicle air conditioner is also reduced in size. The decrease in the compressor capacity due to the miniaturization has been studied in the direction of compensating the discharge amount by increasing the rotation speed. Therefore, the sliding portion of the air conditioning compressor is also subjected to severer sliding like the rocker arm 11. Will be exposed to the conditions.

Among them, the slider 21 shown in FIG. 7 which is used in a variable capacity type swash plate type compressor and which is used to prevent rotation of the swash plate is a typical example. The slider 21 receives the rotation of the swash plate on the sliding surface of the slider guide 22, and further performs a reciprocating sliding movement in the arrow direction. As described above, such parts are also becoming smaller and faster, and are being exposed to more severe sliding conditions.

Conventionally, in order to improve the characteristics of the sliding portion, there are many cases in which the sliding surface is subjected to chrome plating or nitriding treatment, and for those with severe sliding conditions, the vapor phase vapor deposition method is used. The adoption of a hard coating was considered.

[0015]

However, the above surface treatment cannot be said to be sufficient under the severe sliding conditions which are expected to be adopted in the future. Insufficient resistance, and hard coatings obtained by vapor deposition have a very smooth finish due to consideration of attack on the mating material, resulting in poor oil retention and seizure resistance. There is a problem that it is not sufficient, and it has been a problem to eliminate such a problem.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a sliding member having sufficient seizure resistance and abrasion resistance even under more severe sliding conditions. Is intended.

[0017]

DISCLOSURE OF THE INVENTION The present invention focuses on a hard film by a vapor deposition method which has sufficient characteristics in wear resistance, and forms a hard film on the sliding surface by vapor deposition to obtain a hard coating. By forming minute irregularities on the surface of the coating, we intentionally created a state in which oil accumulation is likely to occur, making it possible to hold and supply oil on the sliding surface and improve seizure resistance. It is a thing.

That is, the sliding member according to the present invention has a hard coating film formed by vapor deposition on the surface of the sliding member body, and the surface of the hard coating film has a surface roughness Rz of 0.5 to 1.0.
It is characterized in that it has a structure having fine irregularities of μm.

Further, in the method for producing a sliding member according to the present invention, a hard coating having a large surface roughness is formed on the surface of the sliding member main body by a vapor deposition method, and then the surface of the hard coating is roughened. It is characterized in that a finishing process such as a polishing process or shot blasting for forming fine irregularities of 0.5 to 1.0 μm in Rz display is performed.

FIG. 1 shows an embodiment of a sliding member and a method for manufacturing the same according to the present invention. As shown in FIG. 1 (a), the sliding member body 1a is partially covered with a surface. Finish polishing is performed to such an extent that the rough surface 1b remains.

At this time, the surface of the sliding member main body 1a is not finished to be a mirror surface, and finish polishing processing is performed to the extent that some rough surface 1b remains, so that the adhesion of the hard film formed thereafter is good. Try to be

Next, as shown in FIG. 1B, the rough surface 1
The hard coating 2 is formed on the surface of the sliding member body 1a whose surface has been polished by b, by the vapor deposition method. Here, the reason why the hard film 2 is formed by the vapor deposition method is that the hard film 2 having the unevenness 2a having a relatively large surface roughness is formed.

As described above, the hard coating 2 of metal nitride, metal carbide, metal carbonitride or the like is formed by the vapor deposition method. The hard coating 2 is formed on the surface of the sliding member body 1a.
Is desirable to have a film thickness of 1 μm or more in consideration of the fact that the surface layer disappears due to abrasion in the initial familiarization and the abrasion resistance is impaired. Further, it is preferable that the surface is free from defects such as cracks and chips. It is desirable that the film thickness is 10 μm or less in order to maintain the adhesion.

Before the hard coating 2 is formed, the surface of the sliding member body 1a is sputter-cleaned to sufficiently activate the treated surface, and thereafter the film is formed by the vapor deposition method. Hard coating 2 having irregularities 2a having high adhesion and relatively large surface roughness
It is also desirable in some cases to form a.

Next, as shown in FIG. 1 (c), the surface of the hard coating 2 is subjected to polishing, and polishing such as polishing to such an extent that the relatively rough projections of the unevenness 2a are removed to leave recesses. As a result, the surface roughness Rz is displayed in the range of 0.5 to
The fine unevenness 3 of 1.0 μm is formed. Then, the sliding member 1 in which such fine irregularities 3 act as an oil sump is obtained.

[0026]

The sliding member according to the present invention has a hard coating formed by vapor deposition on the surface of the sliding member body, and the surface of the hard coating has a surface roughness Rz of 0.5 to 1.0 .mu.m. Since it is configured to have fine irregularities, the presence of such fine irregularities forms a state in which oil easily accumulates, and the oil is retained and supplied well on the sliding surface. The seizure resistance and wear resistance are improved.

[0027]

EXAMPLE In the same process as shown in FIG. 1, SKD11 was used as the material of the sliding member main body 1a, and the sliding surface was ground and polished by a surface grinder and a polishing machine to show 0 in terms of surface roughness Rz. By finishing up to 0.5 μm or less, a substantially flat surface having a small rough surface 1b was formed.

Then, on the surface of the sliding member body 1a,
Coating hardness is 1 by arc type ion plating method
Hard film 2 made of chromium nitride of 700 Hmv was formed. Since the surface of the hard coating 2 is rough, the surface roughness is comparatively large, and the surface roughness Rz represents relatively large irregularities 2a of about 1.8 μm.

Subsequently, the uneven portion 2a is finished by a polishing machine to remove the convex portion, and the surface roughness Rz is 0.4 μm, 0.5 μm, 0.7 μm.
After obtaining a sliding member 1 having five types of unevenness 3 of 1.0 μm and 1.4 μm, it was subjected to a seizure test and an abrasion test.

Of these, the seizure test was carried out using the seizure test apparatus shown in FIG. In this seizure test apparatus, a disk-shaped stator (counterpart material) 42 having a diameter of 80 mm is detachably attached to the stator holder 41, and lubricating oil is injected into the center of the stator holder 41 from the back side through the lubrication hole 43. Has become. Here, a surface pressure (P) is applied to the stator holder 41 at a predetermined pressure by a hydraulic device (not shown) toward the right in the drawing.

Further, the test piece holder 45 mounted on the rotor 44 facing the disk-shaped stator 42 is provided with three mounting holes at equal intervals on a circle concentric with the rotating shaft. A test piece (selected from the above five types of sliding members 1) 46 is attached to each.

Then, the test piece 46 is 5 mm × 5 m
The tip end surface of m contacts the sliding surface of the disk-shaped stator 42, rotates at a predetermined speed by a drive device (not shown), and at the time of the test, lubrication oil of a constant temperature is applied to the sliding surface from the lubricating hole 43 on the stator 42 side. Do it while supplying.

When the rotor 44 is rotated, the test piece 4
Torque is generated in the stator holder 41 by friction between the stator 6 and the stator 42. The torque is also detected by a load cell (not shown) via a spindle (not shown), torque fluctuations due to changes in surface pressure are read by a dynamic strain gauge (not shown), and it is determined that seizure has occurred when the torque suddenly rises. Was the surface pressure at which seizure occurred.

The stator 42 has an SCM420H.
And SKD 11 was used for the rotor 44.

On the other hand, the abrasion test was carried out using the abrasion tester shown in FIG. In this abrasion tester, the pin holder 51 has a length of 15 mm with a cross section of 5 mm × 5 mm.
The pin-shaped test piece 52 (selected from the above 5 kinds of sliding members 1) 52 was fixed by screws. The tip of the pin-shaped test piece 52 provided at this time was R6. Here, a surface pressure is applied to the pin holder 51 at a constant pressure in the left direction in the drawing by a hydraulic device (not shown).

A drum (opposite material) 53 facing the pin-shaped test piece 52 is fitted and fastened to a shaft 54 and rotated at a constant speed by a rotation mechanism (not shown).

Then, the abrasion test was carried out while supplying the lubricating oil maintained at a constant temperature from the oiling nozzle 55 to the sliding surface. Here, the material used for the test is the same material as the stator 42 of the seizure test on the drum 53 side, and the pin holder 5
One side was the same as the rotor 44 of the seizure test.

Baking Surface Pressure Test For each combination of the stator 42 made of SCM420H and the test piece 46 attached to the rotor 44,
A seizure surface pressure test was performed using the seizure test apparatus shown in FIG. In this seizure surface pressure test, the surface pressure when the frictional force between the test piece 46 attached to the rotor 44 and the stator 42 suddenly rises was defined as the seizure occurrence surface pressure.

The test conditions are as shown in Table 1 below.

[0040]

[Table 1]

Abrasion test For each combination of the drum 53 made of SCM420H and the pin-shaped test piece 52, an abrasion test was conducted using the abrasion test apparatus shown in FIG. In this wear test, the wear resistance was evaluated by the width of the friction mark of the pin-shaped test piece 52 and the wear depth of the drum 53 after sliding for a certain distance.

The test conditions are shown in Table 2 below.

[0043]

[Table 2]

The result of the seizure surface pressure test is shown in FIG. 4, and the result of the abrasion test is shown in FIG.

As shown in FIG. 4, in the seizure surface pressure test, seizure occurred at a surface pressure of about 28 to 35 MPa at the rotor side test piece surface roughness Rz 0.4 μm, which is the current finish roughness shown in Comparative Example E. However, even in the rotor side test piece surface roughness Rz 1.4 μm shown in Comparative Example A, about 30 to 36 M was obtained.
Seizure occurred at a surface pressure of Pa. On the other hand, the rotor-side test piece surface roughness Rz shown in Examples B, C, and D of the present invention
With 0.5 μm, 0.7 μm, and 1.0 μm, the seizure load is about 32 MPa or more, and the seizure occurrence surface pressure is about 17%.
It was improved, reaching a maximum of 41 MPa, and the effect of oil accumulation due to the formation of the fine irregularities 3 on the surface of the hard coating 2 was recognized.

Further, as shown in FIG. 5, in the abrasion test,
No difference was found in the amount of wear between the current mirror-finished product and the product of the present invention, demonstrating that the product has good wear resistance. However,
As shown in Comparative Example A, the surface finish roughness is Rz 1.0.
When it exceeds 1.4 μm and reaches 1.4 μm, it is the mating drum 5
It was observed that 3 was worn out a lot, and the wear of itself was also increased.

When the results of the seizure surface pressure test and the abrasion test are taken together, the surface roughness of the hard coating 2 is Rz 0.5 to 1.0 μm.
By finishing so that fine irregularities 3 remain between
It was possible to obtain sliding characteristics superior to those of the conventional mirror-finished products.

Further, it is clear that the same effect can be obtained by intentionally forming irregularities on the surface by shot blasting or the like and finally finishing.

[0049]

The sliding member according to the present invention has a hard coating formed by vapor deposition on the surface of the sliding member main body, and the surface of the hard coating has a surface roughness Rz of 0.5 to 1.0 μm. It is confirmed that it is possible to improve abrasion resistance and seizure resistance because it has a structure that has minute irregularities. Was done. And because it has such excellent sliding characteristics, it is optimal for sliding members that will be used under more severe lubrication conditions expected in the future. For example, higher surface pressure and high speed sliding are required. It is now possible to manufacture a rocker arm that can be used, and a more compact slider for a swash plate compressor.

In addition, the method of manufacturing a sliding member according to the present invention has a remarkably excellent effect that the sliding member having excellent wear resistance and seizure resistance can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view illustrating the steps of a method for manufacturing a sliding member according to the present invention.

FIG. 2 is an explanatory diagram showing an outline of a printing test apparatus.

FIG. 3 is an explanatory diagram showing an outline of a wear test device.

FIG. 4 is a graph showing the results of a seizure surface pressure test.

FIG. 5 is a graph showing the results of a wear test.

FIG. 6 is a schematic explanatory diagram of a valve operating mechanism using a rocker arm in an internal combustion engine.

FIG. 7 is a general schematic explanatory diagram of a swash plate rotation preventing mechanism in a one-sided swash plate compressor used for an on-vehicle air conditioner.

[Explanation of symbols]

 1 Sliding member 1a Sliding member main body 2 Hard coating 3 Fine unevenness

Claims (2)

[Claims] 1. A surface of the sliding member body has a hard coating formed by vapor deposition, and the surface of the hard coating has fine irregularities of 0.5 to 1.0 μm in terms of surface roughness Rz. A sliding member characterized by. 2. A hard coating having a large surface roughness is formed on the surface of the sliding member body by a vapor deposition method, and the surface of the hard coating has a surface roughness Rz of 0.5 to 1.0 μm. A method for manufacturing a sliding member, characterized in that finishing is performed to form irregularities.