JPH03134158A - Sliding member - Google Patents

Abstract

PURPOSE:To secure the characteristics of a CrN layer and to improve the conformability of a base material by forming a CrN layer on the sliding surface of a base material and further forming a Cr layer on the surface of the above CrN layer. CONSTITUTION:A piston ring 4 as a base material for a sliding member is fitted in a ring groove 3 in the outside periphery of a piston 2 corresponding to a cylinder liner 1 of an engine, and a CrN layer 6 is formed on a sliding surface 5. At this time, since delicate ruggednesses 7, 8 exist at the surfaces of the cylinder liner 1 and the piston ring 4, respectively, and a part 9 of the CrN layer does not easily wear, conformability between the cylinder liner 1 and the piston ring 4 is poor. Therefore, a Cr layer 10 is further formed on the CrN layer 6 so that the thickness of this Cr layer 10 is greater than the fall (a) of the ruggedness in the CrN layer 6. By this method, conformability can be improved by means of the wear of the Cr layer 10 while securing the characteristics of the CrN layer 6.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a sliding member.

[Prior Art] Sliding members used in engines include piston rings,
There are various types such as tappets, valve stems, rocker arms, gear shafts, etc.

Among these, as an example of a conventional sliding member, a piston ring will be described with reference to FIG. 5 and FIG. 6.

In the diagram, 1 is the engine cylinder liner, 2 is the piston, and 3 is the engine cylinder liner.
is a ring groove formed on the outer periphery of the piston 2, 4 is a piston ring as a base material of a sliding member fitted into the ring groove 3, 5 is a sliding surface of the piston ring 4, and 6 is the sliding surface This is a layer of CrN formed in No. 5.

The extremely hard CrN layer 6 formed on the sliding surface 5 of the piston ring 4 fitted around the outer periphery of the piston 2 improves the pressure wear resistance and seizure resistance of the piston ring 4.
Wear and seizure of the piston ring 4 when the piston 2 slides within the cylinder liner 1 is prevented.

[Problems to be Solved by the Invention] However, the sliding member using the CrN layer 6 has the following problems.

That is, as shown in FIG. 7, the surfaces of the cylinder liner l and piston ring 4 have countless subtle irregularities 7.8 during manufacturing.
In the absence of the extremely hard CrN layer 6, these delicate irregularities would wear away as the piston ring 4 repeatedly slides against the cylinder liner l, causing the surface portion 9 of the piston ring 4 to become uneven. As it wears down, the surface of the piston ring 4 approaches a smooth arc shape.
The compatibility between the piston ring 4 and the cylinder liner l improves, but when the extremely hard C and H layers 6 are formed on the sliding surface 5 of the piston ring 4, the portion of the CrN layer 6 Since the piston ring 9 does not wear out easily, the cylinder liner l and the piston ring 4 do not fit together for a long time, resulting in extremely poor compatibility.

In view of the above-mentioned circumstances, it is an object of the present invention to provide a surface coating for a sliding member that has improved conformability while ensuring wear resistance and seizure resistance with a CrN layer. .

[Means for solving the problem] The present invention forms a CrN layer on the sliding surface of the base material, and
The present invention relates to a sliding member characterized in that a C layer is formed on the surface of the CrN layer.

[Function] Due to the extremely hard CrN layer formed on the sliding surface of the base material,
The wear resistance and seizure resistance of the base material are ensured.

C, which is softer than the C and H layers formed on the surface of the CrN layer.
The r layer is worn as the base material slides, and the unevenness on the surface is worn away, so the surface becomes smooth and the conformability of the base material is improved.

[Implementation example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention.

In the diagram, 1 is the engine cylinder liner, 2 is the piston, and 3 is the engine cylinder liner.
is a ring groove formed on the outer periphery of the piston 2, 4 is a piston ring as a base material of a sliding member fitted into the ring groove 3, 5 is a tm moving surface of the piston ring 4, and 6 is the sliding surface. The CrN layer formed on the surface 5, 7 and 8 are the unevenness on the cylinder liner l and the piston ring 4 surface, respectively, and 9 is the part of the unevenness 8 on the piston ring 4 surface that should be worn out in order to improve conformability.

C and N layer B formed on the sliding surface 5 of the piston ring 4
A layer 1O of C' is formed on the surface of.

FIG. 3 shows an apparatus for forming a layer of cr N 6 and a layer of Cr IO on a piston ring 4 at once.

In the figure, 11 is a chamber, 12 is a gas port formed in the chamber 11 for supplying N2 (nitrogen) gas 13, 14 is a valve provided in the middle of the gas port 12, and 15 is a gas formed in the chamber 11. an exit, 16 a crucible placed in chamber 11, 17 c placed in crucible 1, 18 an electron gun that emits an electron beam 19 toward Cr17 in crucible IB;
Reference numeral 20 indicates a conductive rotating shaft which is provided at a position away from the crucible 16 in the chamber 11 and has a large number of piston rings 4 fitted thereon, 21 is a motor that rotationally drives the rotating shaft 20, and 22 is a negative motor connected to the rotating shaft 20. 23 is a probe electrode placed between the crucible 16 and the rotating shaft 20 in chamber 11; 24 is a power source that applies a positive voltage to the probe electrode 23;

A layer 6 of CrN and a layer l of C on the surface of the piston ring 4.
To form O, proceed as follows.

That is, as shown in FIG. 3, the valve 14 is opened and the gas inlet 1 is
Room from 2! N2 gas 13 is supplied into the chamber 11, and the atmosphere inside the chamber 11 is set to the N2 gas 13.

At this time, the excess N2 gas 13 in the chamber 11 is removed from the gas outlet 15.
It is discharged to the outside of the chamber 11 through.

Next, the electron beam 19 from the electron gun 18 heats and melts the Cr17 in the crucible 1θ. Thermionic electrons are generated in the vapor of Cr17 evaporated at this time.

At the same time, when a positive voltage is applied to the probe electrode 23 by the power source 24, the vapor of Cr17 that is generating thermoelectrons is attracted to the probe electrode 23, which causes a discharge phenomenon, and the energy of the discharge causes the Cr17 Steam and N2 gas 13 are ionized and activated.

In this state, when a negative voltage is further applied to the rotating shaft 20 by the power supply 22 and the rotating shaft 20 is driven to rotate by the motor 21, the ionized and activated Cr17 vapor and the N2 gas 13 react to produce C, N is deposited on the sliding surface 5 of the piston ring 4 fitted on the rotating shaft 20, and C is deposited on the sliding surface 5.
A layer 6 of rN is formed.

When the C, N layer 6 formed in this way reaches a predetermined thickness, the valve 14 is closed to stop the supply of N2 gas 13 from the gas port 12, and the gas outlet 1 is closed using a blower (not shown) or the like.
The above operation is continued while exhausting the N2 gas 13 in the chamber 1 from 5.

Then, the N2 gas 13 disappears or becomes diluted in the chamber 11, so that a C layer 10 is formed on the surface of the CrN layer 6 of the piston ring 4. Note that the C layer 10 is made thicker than the height a of the unevenness of the CrN layer 6 shown in FIG.

In this way, the piston ring 4 in which the C layer 1O is formed on the surface of the CrN layer B has wear resistance and seizure resistance due to the CrN layer 6.

Moreover, as shown in FIG. 4, the layer 10 of C formed on the surface of the CrN layer B is softer than the CrN layer 6, so as the piston ring 5 slides against the cylinder liner 1, it becomes uneven. As the portion 9 of the piston ring 8 wears away, the surface of the piston ring 4 approaches a smooth arc shape, so that the conformability between the piston ring 4 and the cylinder liner l improves.

Note that the sliding member of the present invention is not limited to the above-mentioned embodiments, and can be used in addition to piston rings as well as sliding members used in engines such as tappets, valve stems, rocker arms, gear shafts, and other non-engine parts. It goes without saying that the present invention is also applicable to sliding members, and that various changes can be made without departing from the gist of the invention.

[Effects of the Invention] As explained above, according to the sliding member of the present invention, a Cr layer that is softer than a CrN layer is formed on the surface of the C and H layers formed on the sliding surface of the base material. Therefore, while the wear resistance and seizure resistance of the C and H layers are maintained, the C layer is worn away and the surface irregularities are abraded, improving the conformability of the base material. It can have excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of one embodiment of the sliding member of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a cross-sectional view of an embodiment of the sliding member of the present invention. A schematic diagram of the device, FIG. 4 is a view taken along the line IV-IV in FIG. 1, FIG. 5 is a side sectional view showing an example of a conventional sliding member, and FIG. 6 is a partially enlarged view of FIG.
FIG. 7 is a view taken along the ■-■ arrow in FIG. In the figure, 4 indicates a piston ring as a base material, 5 indicates a sliding surface of the piston ring, 6 indicates a CrN layer, and IO indicates a C0 layer. Figure 1

Claims (1)

[Claims] 1) Form a CrN layer on the sliding surface of the base material, and
A sliding member comprising a Cr layer formed on the surface of an N layer.