JP2002372127A - Shim with dlc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the slide wear between a cam and a follower or a tappet used in a power transmission system for controlling the opening/closing of a fuel valve of an engine. SOLUTION: In a shim formed of a metal material which is used in a transmission system to transmit the driving force by the rotational motion of the cam to a reciprocating member, an intermediate layer comprising at least one kind of metal film selected from (a) a silicide or silica-carbide mainly consisting of at least one selected from 5A group metal (V, Nb and Ta), 6A group metal (Cr, Mo and W), Ti and Zr, (b) a metal film mainly consisting of at least one kind selected from 5A group metal (V, Nb and Ta) and an Si film or a metal film mainly consisting of Si which is formed thereon, or (c) a metal film of at least one kind selected from 5A group metal (V, Nb and Ta), 6A group metal (Cr, Mo and W), Ti, and Zr, and a silicon carbide film formed thereon, and at least one layer of diamond-like carbon film are formed in this order on a surface of the shim which is slidably engaged with the metal cam fixed to the surface of the reciprocating member. Alternatively, a diamond-like carbon film containing at least H, Si and O is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shim made of a metal material used in a power transmission system for converting a driving force due to a rotational motion of a cam into a reciprocating motion in an internal combustion engine of an automobile or the like. Regarding the shim provided.

[0002]

2. Description of the Related Art In an internal combustion engine such as an automobile engine,
2. Description of the Related Art A power transmission system for transmitting a driving force due to a rotational motion of a cam to a fuel valve or the like via a reciprocating member such as a tappet is used. Since the cam is in contact with the contact object, for example, the surface of a shim fixed to the tappet, so as to transmit the driving force to the tappet and slides while receiving a high surface pressure, the cam surface and the shim surface are severely worn and damaged. Become. Especially in the case of an OHC (overhead camshaft) type engine, it is important to adjust the interval between the cam and the tappet (or shim).
If these adjustments are inadequate, they may cause problems such as a source of noise, or even if the adjustments are made, if the wear of these parts is severe, they will deviate from the desired interval. This could cause a reduction in horsepower and a reduction in fuel economy. In addition, there is a possibility that it may become unusable due to galling with the partner material.

FIG. 1 shows a power transmission system for opening and closing a fuel valve. FIG.
The cam 3 fixed to the shaft 1 driven by a crankshaft that transmits the engine output rotates while sliding on the lower surface of the tappet 7. This allows the tappet 7 to reciprocate.
Transmits power to one end of the rocker arm 13 supported on the rocker arm shaft 15 via the push rod 9 to swing it. The other end of the rocker arm 13 is
The fuel rod 23 is opened and closed by pressing the valve rod 21 supported by the spring 17 held at the timing by the timing of the cam 3,
Supply fuel to the piston / cylinder of the engine. The interval between the camshaft 1 and the shim 5 is adjusted by an adjusting screw 11. FIG. 2 shows an example of a transmission system using a double overhead cam (DOHC) system, which is a kind of the OHC system, in which cams 3 and 3 fixed to shafts 1 and 1 'driven by a crankshaft for transmitting engine output. 'Is the tappet 7,
It rotates while sliding on the upper surface of 7 '. As a result, the reciprocating tappets 7, 7 'are provided with a retainer 1 therein.
The fuel rod 23 and the exhaust valve 23 'are opened and closed by pressing the valve rods 21 and 21' supported by the springs 17 and 17 'held at 9 and 19' at the timing of the cams 3 and 3 ', and the fuel is supplied to the engine. And exhaust to the piston / cylinder.

The contact surface between the cam and the tappet is subjected to a greater frictional action depending on the distance between them and the force of the spring 8, so that there is sufficient low friction between the cam surface and the contact surface of the mating member. And it is necessary to impart abrasion resistance. In order to solve this problem, Japanese Patent Application Laid-Open No. H11-280419 discloses FIG.
It is described that a shim made of a diamond-like carbon film (DLC) having high abrasion resistance is provided on the end face of the tappet 7 in contact with the cam 3 as shown in FIG. However, the document describes that a shim made of a diamond-like carbon film alone cannot provide sufficient wear resistance, and that the cam surface must be precisely polished to an Ra of 0.08 μm or less. As another countermeasure, JP-A-11-280419 discloses a method in which a material having a hardness higher than that of the cam sliding surface, for example, a diamond-like thin film is coated on a metal alloy base material, and the surface is coated with a ten-point average surface roughness R.
It describes a combination of a shim having a z of 0.07 to 0.2 μm and a cam having an open pore for holding a large number of lubricating oils such as sintered metal.

[0005]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. H11-2804
In the technique described in No. 19, there is a problem that the cam surface must be mirror-polished to 0.08 μm or less in Ra with respect to a shim made of a diamond-like carbon film having high wear resistance. The step of polishing the cam surface is a time-consuming and time-consuming step, and is inefficient and costly. On the other hand, in the technique described in Japanese Patent Application Laid-Open No. H11-280419, the finished surface of the shim may be relatively rough, but a large number of open pores must be formed in the cam sliding surface to hold lubricating oil there. There's a problem. SUMMARY OF THE INVENTION It is an object of the present invention to provide a shim with improved wear resistance without the necessity of precisely polishing a cam surface or a shim surface.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an improvement in a shim made of a metal material used in a transmission system for transmitting a driving force due to a rotational movement of a cam to a reciprocating member.

Shim (1) According to the present invention, there are provided (a) a Group 5A metal (V, Nb, Ta), and a 6A on a surface of the shim fixed to a surface of the reciprocating member so as to slide on a cam. Group metals (Cr, Mo,
W) a silicide or silicide mainly composed of at least one selected from Ti and Zr; (b) a metal mainly composed of at least one selected from Group 5A metals (V, Nb, Ta) A film and a Si film formed thereon or a metal film containing Si as a main component, or (c) a Group 5A metal (V, Nb, Ta) or a Group 6A metal (Cr, Mo,
W) an intermediate layer composed of at least one metal film selected from Ti, Zr and a silicon carbide film formed thereon, and at least one layer of a diamond-like carbon film formed in this order. Provide a sim to do. (2) In the above, the diamond-like carbon film is composed of carbon and hydrogen, and when its composition is represented by a molar ratio of CHn, a diamond-like carbon film represented by 0.05 ≦ n ≦ 0.7, or , Containing silicon, and may contain oxygen, nitrogen, and fluorine.
When represented by xSiyOzNvFw, a diamond represented by the following formula: 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 0 ≦ v ≦ 1.0 0 ≦ w ≦ 0.2 It consists of at least one layer of a carbon-like film. (3) Preferably, in the above (1), the diamond-like carbon film is formed of CHxSiyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1.00 ≦ w ≦ 0.2) and at least two layers of a diamond-like carbon film represented by CHn (where 0.05 ≦ n ≦ 0.7) Or a layer in which one of these compositions is continuously changed to the other. (4) In another aspect of the present invention, in a shim made of a metal material used for a transmission system for transmitting a driving force due to a rotational movement of a cam to a reciprocating member, the reciprocating movement is performed so as to slide on the cam. The surface of the metal shim fixed to the surface of the member may contain silicon, and may contain oxygen, nitrogen and fluorine. When the composition is represented by CHxSiyOzNvFw, 0.05 ≦ x ≦ 0.7 0.01 ≦ At least one layer of a diamond-like carbon film represented by y ≦ 3.0 0 ≦ z ≦ 1.00 0 ≦ v ≦ 1.00 ≦ w ≦ 0.2 is formed. (5) In the above (4), the diamond-like carbon film is formed of CHxSiyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1. 0 ≦ w ≦ 0.2) and at least two layers of a diamond-like carbon film represented by CHn (0.05 ≦ n ≦ 0.7) formed thereon. Or a layer in which these compositions are continuously changed from the former composition to the latter composition.

Combination of shim and cam (6) In another embodiment of the present invention, the above (1) to (1)
(5) In any one of the combinations of the shim and the cam, a diamond-like carbon film is formed on a surface of the cam that is slidably engaged with the shim. (7) In this case, the diamond-like carbon film is composed of carbon and hydrogen, and when its composition is represented by a molar ratio of CHn, the diamond-like carbon film is represented by 0.05 ≦ n ≦ 0.7. , And silicon,
Oxygen, nitrogen and fluorine may be contained, and the composition is CHxS
When represented by iyOzNvFw, diamond represented by the following formula: 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.0 0 ≦ v ≦ 1.0 0 ≦ w ≦ 0.2 It consists of at least one layer of a carbon-like film. (8) Preferably, in the above (6), the diamond-like carbon film is formed of CHxSiyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1 0.00 ≦ w ≦ 0.2), and at least two layers of a diamond-like carbon film represented by CHn (where 0.05 ≦ n ≦ 0.7). Alternatively, a layer is formed in which one of these compositions is continuously changed from the other composition to the other composition. (9) More preferably, in the above (6) to (8),
(A) a group 5A metal (V, Nb, Ta), a group 6A metal (Cr, Mo, W), Ti, or Zr selected between the surface of the cam and the diamond-like carbon film formed on the surface; (B) a metal film mainly composed of at least one selected from Group 5A metals (V, Nb, Ta) and a Si film formed thereon; Or a metal film containing Si as a main component, or (c) at least one metal selected from Group 5A metals (V, Nb, Ta), Group 6A metals (Cr, Mo, W), Ti, and Zr An intermediate layer composed of a film, a silicon carbide film formed thereon, and at least one layer of a diamond-like carbon film are formed in this order.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The present inventors have found that diamond-like thin films (DLC films) formed on shims according to the prior art cause significant wear when used in combination with cams having relatively high surface roughness. As a result of exploring the reason, it was found that there was a problem in the adhesion between the metal substrate of the shim and the diamond-like thin film, which made long-term use impossible. The present inventors have conducted intensive studies and found that by appropriately selecting the material of the diamond-like thin film to be coated on the shim and / or by using an appropriate intermediate layer, the adhesion was improved and the wear resistance was markedly improved. Could be improved. When the shim having the structure of the present invention is employed, the surface roughness of the cam is 0.08 μm.
m is not required to be precisely polished, and sufficient abrasion resistance is provided even with a surface roughness greater than 0.1 μm.

That is, according to the present invention, (a) a Group 5A metal (V, Nb, Ta) and a Group 6A metal (Cr, Mo,
W) a silicide or silicide mainly composed of at least one selected from Ti and Zr; (b) a metal mainly composed of at least one selected from Group 5A metals (V, Nb, Ta) A film and a Si film formed thereon or a metal film containing Si as a main component, or (c) a Group 5A metal (V, Nb, Ta) or a Group 6A metal (Cr, Mo,
An intermediate layer comprising at least one metal film selected from W), Ti, and Zr and a silicon carbide film formed thereon is provided. When such an intermediate layer is formed, the diamond-like carbon film is not particularly limited. A diamond-like carbon film containing H, a diamond-like carbon film containing H and Si, a combination thereof, or a diamond-like carbon film that continuously changes its composition from one to the other can be used. .

Further, according to the present invention, the abrasion resistance can be greatly improved by forming a diamond-like carbon film containing H and Si on at least the surface of the shim without using an intermediate layer. Becomes In this case, a diamond-like carbon film containing H can be further formed on the diamond-like carbon film containing H and Si, and further improvement in wear resistance can be expected. Hereinafter, the diamond-like carbon film may be abbreviated as DLC for simplicity. or,
In the present invention, in addition to treating the shim as described above, the wear resistance can be further improved by forming a diamond-like carbon film on the cam surface directly or with an intermediate layer interposed.

As the material which can be used as the base material of the cam and the shim in the present invention, any material conventionally used in the art can be used. Examples of these materials include various types of carbon steel and cast iron (gray cast iron, spheroidal graphite cast iron, malleable cast iron, alloy cast iron, etc.), cast steel and the like, and ultra-high toughness steel (SNCM).
420, SCM440, SCM420, SCR420,
H11), high-speed tool steel (high-speed steel: JIS standard SKH), alloy tool steel (die steel: SKD6, etc.),
Maraging steel (KMS180-20 etc.), ausform steel, stainless steel (SUS304, SUS430,
17-4PH), bearing steel (such as SUJ2), Al alloy (such as AC4C), and Ti alloy.

[0013] The metal used as the base material may be quenched under appropriate conditions to improve the hardness of the material. For quenching, for example, induction hardening, flame quenching, carburizing quenching and the like can be used. Further, a surface hardening treatment may be performed on these substrates or on the quenched substrate, and a diamond-like carbon film or a diamond-like carbon film may be coated thereon with an intermediate layer interposed therebetween. Examples of the surface hardening include nitriding, carburizing, and boring.

Intermediate Layer Next, the intermediate layer used in the present invention comprises (a) a Group 5A metal (V, Nb, Ta) and a Group 6A metal (Cr, Mo,
W) a silicide or silicide mainly composed of at least one selected from Ti and Zr; (b) a metal mainly composed of at least one selected from Group 5A metals (V, Nb, Ta) A film and a Si film formed thereon or a metal film containing Si as a main component, or (c) a Group 5A metal (V, Nb, Ta) or a Group 6A metal (Cr, Mo,
W), at least one metal film selected from Ti and Zr, and a silicon carbide film formed thereon.
178736, 2000-178737, 2000
177,046, 2000-178,738, 200
0-90842 and the like.

In the case of the intermediate layer (a), the composition is MSi
aCb (where M is V, Nb, Ta, Cr, Mo, W,
At least one of Ti and Zr), 0.3 ≦ a ≦ 10, preferably 1 ≦ a ≦ 6, 0 ≦ b
≦ 5, preferably 0 ≦ b ≦ 3, 0.3 ≦ a + b ≦ 10,
Preferably, 1 ≦ a + b ≦ 6. If a is larger than this and the amount of silicon increases, the adhesion to the base material deteriorates. If a is smaller than this and silicon is small, the adhesion to the DLC film will be poor. When b is larger than this and the amount of carbon is large, the adhesion to the base material is deteriorated. When b is smaller than this and carbon is reduced, the adhesion to the DLC film is deteriorated.
Also, if a + b is larger than this, the adhesion to the base material will be poor, and if a + b is smaller than this, the adhesion to the DLC film will be poor.

The thickness of the intermediate layer is preferably 2 nm to 5 μm, more preferably 5 nm to 1 μm. With such a thickness, the adhesion is improved. On the other hand, if the intermediate layer is too thin, the effect of improving the adhesion will not be sufficient, and if it is too thick, the impact resistance will deteriorate.

The intermediate layer of the present invention can be formed by a PVD method such as a vacuum evaporation method, a sputtering method, an ion plating method, or a thermal CVD method.
It can be formed by a CVD method such as a plasma CVD method, a photo CVD method, or the like. Wet plating, thermal spraying,
It may be formed by clad bonding or the like. Specifically, a known method is used. In particular, the intermediate layer of the present invention is preferably formed by a sputtering method. In this case, using a target corresponding to the target composition, high-frequency power, AC power, or any of DC power is added, the target is sputtered,
This is sputter deposited on a base material (substrate) to form an intermediate layer.

Usually, the target may have the same composition as that of the intermediate layer. However, it may be a multi-source sputtering which targets a metal such as Ta and a metal such as Si, or C or Si by reactive sputtering. When introducing, a target not containing the component can be used.

As the sputtering gas, an inert gas used in a usual sputtering apparatus can be used. Above all, Ar, K
r or Xe, or at least one of these
It is preferable to use a mixed gas containing at least one kind of gas.
Reactive sputtering may be performed. When carbon is introduced as a reactive gas, CH ₄ , C ₂ H ₂ , C ₂ H
_{4. When} introducing silicon using CO or the like, silane gas or the like is used. When hydrogen is introduced, H ₂ or the like is used. These reactive gases may be used alone or as a mixture of two or more. The operating pressure during sputtering is preferably in the range of 0.2 to 70 Pa. Further, by changing the pressure of the sputtering gas within the above range during the film formation, an intermediate layer having a concentration gradient can be easily obtained.

As the sputtering method, a high frequency sputtering method using an RF power source or a DC sputtering method may be used. The power of the sputtering apparatus is about 0.5 to 30 W / cm ^{2 for} DC sputtering, 1 to 50 MHz for high frequency sputtering, and 50 kHz to 1 MHz for low frequency.
It is preferably about 0.5 to 30 W / cm ² . The deposition rate is 1
The range of -300 nm / min is preferable. Further, the substrate temperature is preferably 10 to 150 ° C.

Further, the intermediate layer of the present invention may be formed by a vapor deposition method. The evaporation method may be a resistance heating method or an electron beam heating method. The evaporation source is Ta
Or a single vapor deposition using the same composition as the intermediate layer. 1
Even in the original deposition, a film composition substantially the same as the composition of the deposition source can be obtained stably with time. The conditions for vacuum deposition are not particularly limited, but the degree of vacuum is 10 ⁻³ Pa or less, particularly 10 ⁻⁴ Par.
The following is preferred. The deposition rate is usually 1 to 300 nm /
min is preferable.

The intermediate layer can also be formed by a plasma CVD method or an ionization vapor deposition method.
The film may be formed with reference to the LC film.

Diamond-like carbon film A diamond-like carbon (DLC) film is sometimes called a diamond-like carbon film, an i-carbon film, or the like. The diamond-like carbon film is disclosed in, for example, JP-A-62-14.
Nos. 5646 and 62-145647, New
Diamond Forum, Vol. 4 No. 4 (Showa 6
Issued October 25, 2013).

The DLC film is described in the above-mentioned reference (New Diam).
as described in Raman
1550 cm for spectroscopic analysis^-1(15
20-1560cm^-11) having a peak of Raman absorption;
333cm^-1Diamonds with sharp peaks at
581cm^-1Graphite with a sharp peak at
It is a substance with a distinctly different structure. DLC film
The absorption peak in Raman spectroscopy is 1 as described above.
550cm ^-1Broad to (1520 ~ 1560cm^-1)
But has the above-mentioned elements other than carbon and hydrogen.
By having, from now on ± 100cm^-1Fluctuate
In some cases. The DLC film mainly contains carbon and hydrogen.
A thin film in an amorphous state, wherein the carbon-to-carbon sp3
Formed by the random presence of bonds
You. When the DLC film is represented by CHn, the molar ratio is 0.05
≦ n ≦ 0.7.

In the present invention, the thickness of the DLC film is usually 1 to 10 μm, preferably 10 nm to 3 μm.

The DLC film is made of Si in addition to carbon and hydrogen.
And one or more of O, N, and F may be contained. When the intermediate layer is not used, at least the first layer is made of Si in addition to hydrogen in order to improve the adhesion to the base material.
Should be contained. In this case, the DLC film is CHxS
When expressed as iyOzNvFw, x, y, z, v, and w are respectively 0.05 ≦ x ≦ 0.7, 0.01 ≦ y ≦ 3.
0, 0 ≦ z ≦ 1.0, 0 ≦ v ≦ 1.0, 0 ≦ w ≦ 0.2
It is preferable that Also, a plurality of layers may be formed, but instead, the composition may be continuously variable in the thickness direction from a portion containing Si to a portion not containing Si.

The DLC film can be formed by a plasma CVD method, an ionization vapor deposition method, a sputtering method, or the like. DL
When the C film is formed by a plasma CVD method, the C film can be formed by a method described in, for example, JP-A-4-41672. Plasma in the plasma CVD method may be either direct current or alternating current, but it is preferable to use alternating current. The alternating current can be used from a few hertz to a microwave. In addition, E described in diamond thin film technology (published by Comprehensive Technology Center), etc.
CR plasma can also be used. Further, a bias voltage may be applied.

When the DLC film is formed by the plasma CVD method, it is preferable to use the following compound as a source gas. Methane, as a compound containing C and H,
Hydrocarbons such as ethane, propane, butane, pentane, hexane, ethylene, propylene and the like can be mentioned. Compounds containing C, H and Si include methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane, tetraethylsilane, tetrabutylsilane, dimethyldiethylsilane, tetraphenylsilane,
Examples include methyltriphenylsilane, dimethyldiphenylsilane, trimethylphenylsilane, trimethylsilyl-trimethylsilane, and trimethylsilylmethyl-trimethylsilane. These may be used in combination, or a silane compound and a hydrocarbon may be used. Compounds containing C + H + O include CH ₃ OH, C ₂ H ₅ OH, HCHO, CH ₃
COCH _{3 and the} like. Examples of the compound containing C + H + N include ammonium cyanide, hydrogen cyanide, monomethylamine, dimethylamine, allylamine, aniline, diethylamine, acetonitrile, azoisobutane, diallylamine, ethylazide, MMH, DMH, triallylamine, trimethylamine, triethylamine, triphenylamine and the like. is there. In addition, Si + C + H, Si
A compound containing + C + H + O or Si + C + H + N may be combined with an O source or an ON source, an N source, an H source, or the like.

O source, O ₂ , O _3, etc .; C + O source, CO, CO ₂ etc .; Si + H source, SiH _4, etc.
As a source, H ₂ or the like, H + O source, H ₂ O, etc., N source, N ₂ N + H source, NH ₃ or the like, N + O source, N
Compounds of N and O, such as O, NO ₂ , and N ₂ O, which can be represented by NOx, such as (CN) ₂ as an N + C source, NH ₄ F as an N + H + F source, and OF ₂ and O ₂ F ₂ as an O + F source. , O
₃ F ₂ or the like may be used.

The flow rate of the raw material gas may be appropriately determined according to the type of the raw material gas. The operating pressure is typically between 1 and 70
Pa and the input power are usually preferably about 10 W to 5 kW.

The DLC film may be formed by an ionization vapor deposition method. The ionization deposition method is described in, for example, Japanese Patent Application Laid-Open No. 58-17 / 1983.
No. 4507, JP-A-59-174508 and the like. However, the present invention is not limited to the methods and apparatuses disclosed therein, and another type of ion vapor deposition technology may be used as long as the ionized gas for the raw material can be accelerated. As a preferable example of the device in this case, for example, an ion straight type or an ion deflection type described in Japanese Utility Model Laid-Open No. 59-174507 can be used.

In the ionization vapor deposition method, the inside of the vacuum vessel is set to a high vacuum of about 10 ⁻⁴ Pa. A filament that is heated by an AC power supply and generates thermoelectrons is provided in the vacuum vessel. A counter electrode is arranged around the filament, and a voltage Vd is applied between the filament and the filament. In addition, an electromagnetic coil that surrounds the filament and the counter electrode and generates a magnetic field for trapping ionized gas is arranged. The source gas collides with the thermoelectrons from the filament to generate positive thermal decomposition ions and electrons, and the positive ions are accelerated by the negative potential Va applied to the grid. By adjusting Vd, Va and the magnetic field of the coil, the composition and film quality can be changed. Further, a bias voltage may be applied.

When the DLC film is formed by the ionization vapor deposition method, the same material gas as that used in the plasma CVD method may be used. The flow rate of the source gas may be appropriately determined according to the type. The operating pressure is usually 1 to 70 Pa
The degree is preferred.

The DLC film can be formed by a sputtering method. In this case, a gas such as O ₂ , N ₂ , NH ₃ , CH ₄ , H ₂ or the like is introduced as a reactive gas in addition to a sputtering gas for sputtering such as Ar or Kr, and C, Si,
Targeting SiO ₂ , Si ₃ N ₄ , SiC, etc.
A target may be a mixed composition of C, Si, SiO ₂ , Si ₃ N ₄ , and SiC, and in some cases, C, Si, N, O
May be used. Further, a polymer can be used as a target. A DLC film is formed by applying any one of high-frequency power, AC power, and DC power using such a target, sputtering the target, and sputter depositing the target on a substrate. The high frequency sputtering power is usually 50 W to 2 k
It is about W. The operating pressure is usually 10 ^{−3 to} 0.1 Pa
Is preferred.

[0035]

Next, embodiments of the present invention will be described. In the combinations shown in Table 1, an intermediate layer and a DLC film were formed on the surface of the shim. All cams and shims are SNCM4
20 were used. The surface roughness of the base material of the examples was all Ra
= 0.1 μm. The shim was placed at a predetermined position in a vacuum chamber, and after evacuation, a film was formed under the following conditions.

<Formation of Intermediate Layer> The intermediate layer was manufactured by the sputtering method under the following conditions. Working gas: Ar (5.1 × 10 ^-2 Pa · m ³ · s ^-1 ) =
30 sccm Sputter pressure: 40 Pa Input power: 500 W Target: Ta, Si Film thickness: Ta (first layer) 10 nm, Si (second layer) 90 n
m

Further, the intermediate layer shown in Table 1 was formed under the same film forming conditions while changing the target. In the case of a single intermediate layer, the thickness was 100 nm.

[0038]

[Table 1]

<Formation of DLC Film> A DLC film was formed by a self-bias RF plasma CVD method under the following conditions. DLC1 source gas: C ₂ H ₄ (0.017 Pa · m ³ · s ⁻¹ ) Power supply: RF Operating pressure: 66.5 Pa Input power: 500 W Film formation rate: 100 nm / min Film composition: CH _0.21 Film thickness: 2 μm DLC2 Source gas: Si (OCH ₃ ) ₄ (0.085 Pa · m ³ ·
s ^-1 ) Power supply: RF Operating pressure: 66.5 Pa Input power: 500 W Deposition rate: 100 nm / min Film composition: CH _0.2 Si _0.1 O _0.17 Film thickness: 2 μm DLC3 source gas: Si (CH ₃ ) ₄ (0. 085 Pa ・ m ³・ s
^-1 ) Power supply: RF Operating pressure: 66.5 Pa Input power: 500 W Film formation rate: 100 nm / min Film composition: CH _0.24 Si _0.22 Film thickness: 2 μm

<Evaluation Method> Durability tests were performed on shims not coated with DLC (Comparative Example) and shims and cams (Examples) coated with DLC under the following conditions. The shims were then compared for wear. The test is DOH
In a car engine using C, a shim is fixed to the surface of the tappet, and the cam is brought into contact and rotated. It should be noted that this condition is an acceleration test corresponding to a much harsher F1 level as compared with the rotational speed (2000 to 4000 rpm) in a general running of a commercial vehicle. The results were as shown in Table 2.

[0041]

[Table 2]

[0042]

As shown in Table 1, the operation of the engine is stopped when the durability time is exceeded. According to the example of the present invention, it can be seen that a shim having extremely high durability could be provided not only in Comparative Example 1 but also in Comparative Example 2 corresponding to a known example using DLC. Examples 1-3
As can be seen from the drawings, in the present invention, excellent durability is obtained despite the fact that the surface of the shim is not subjected to precision polishing as in Comparative Example 2, so that the process can be shortened and the cost can be reduced. . ADVANTAGE OF THE INVENTION According to this invention, adhesiveness can be improved by selecting the material of the diamond-like thin film which coat | covers a shim at least, and / or by using a suitable intermediate | middle layer, and abrasion resistance can be improved remarkably. Was.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a power transmission system including a cam and a tappet to which the present invention can be applied.

FIG. 2 is a cross-sectional view illustrating another structure of a power transmission system including a cam and a tappet to which the present invention can be applied.

FIG. 3 is a diagram showing an example provided with a conventional cam and shim.

[Explanation of symbols]

 1, 1 'camshaft 3, 3' cam 5 shim 7, 7 'tappet 9 thrust rod 11 adjusting screw 13 rocker arm 15 rocker arm shaft 17, 17' spring 19, 19 'retainer 21, 21' valve rod 23 fuel valve 23 'exhaust valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiichi Odaka 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDC Corporation (72) Inventor Yasuhiro Matsuba 1-13-1 Nihonbashi, Chuo-ku, Tokyo Within TDK Corporation (72) Inventor Yasushi Hashimoto 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation (72) Inventor Izumi Miyauchi 1-13-1 Nihonbashi, Chuo-ku, Tokyo TDK Corporation F term (reference) 3G016 AA05 AA08 AA19 BA19 BA34 BB02 BB05 BB06 EA01 EA07 EA08 EA11 EA14 EA16 EA24 FA01 FA04 FA18 FA21 FA22 FA23 GA02 3J030 EA01 EA04 EA21 EB07 EC04 EC07

Claims (9)

[Claims] In a shim made of a metal material used for a transmission system for transmitting a driving force due to a rotational movement of a cam to a reciprocating member, a shim made of metal material is provided on a surface of the reciprocating member so as to slide on the cam. (A) No. 5 on the surface of the fixed shim
Group A metal (V, Nb, Ta), Group 6A metal (Cr, M
o, W), a silicide or silicide containing at least one selected from Ti and Zr as a main component;
A metal film mainly composed of at least one selected from group A metals (V, Nb, Ta) and a Si film or a metal film mainly composed of Si formed thereon, or (c) 5A
Group metal (V, Nb, Ta), Group 6A metal (Cr, M
o, W), an intermediate layer composed of at least one metal film selected from Ti, and Zr and a silicon carbide film formed thereon, and at least one diamond-like carbon film formed in this order. A shim. 2. The diamond-like carbon film is composed of carbon and hydrogen, and when its composition is represented by a molar ratio of CHn, 0.05 ≦ n ≦ 0.7 or silicon is added to the diamond-like carbon film. Oxygen, nitrogen, fluorine may be contained, and the composition is CHxSi
When represented by yOzNvFw, a diamond represented by the following formula: 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 0 ≦ v ≦ 1.00 ≦ w ≦ 0.2 2. The shim according to claim 1, comprising at least one layer of a carbon-like film. 3. The method according to claim 2, wherein the diamond-like carbon film is made of CHxS.
iyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1.00 ≦ w ≦ 0.2) Forming at least two layers of a film and a diamond-like carbon film represented by CHn (where 0.05 ≦ n ≦ 0.7), or continuously changing from one of these compositions to the other 2. The shim according to claim 1, wherein a layer is formed. 4. A shim made of a metal material used for a transmission system for transmitting a driving force due to a rotational movement of a cam to a reciprocating member, wherein the shim is fixed to a surface of the reciprocating member so as to slide on the cam. The surface of the metal shim contains silicon, and may contain oxygen, nitrogen, and fluorine.
When represented by yOzNvFw, a diamond represented by the following formula: 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 0 ≦ v ≦ 1.00 ≦ w ≦ 0.2 A shim comprising at least one layer of a carbon-like film. 5. The diamond-like carbon film is made of CHxS
iyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1.00 ≦ w ≦ 0.2) Forming at least two layers of a film and a diamond-like carbon film represented by CHn (where 0.05 ≦ n ≦ 0.7) formed on the film, or forming the latter from the former composition of these compositions 5. The shim according to claim 4, wherein a layer having a continuously changed composition is formed. 6. A shim according to claim 1, wherein a diamond-like carbon film is formed on a surface of said cam which is slidably engaged with said shim. And cam combination. 7. The diamond-like carbon film is composed of carbon and hydrogen, and when its composition is represented by a molar ratio of CHn, a diamond-like carbon film represented by 0.05 ≦ n ≦ 0.7, and Containing silicon,
Oxygen, nitrogen and fluorine may be contained, and the composition is CHxS
When represented by iyOzNvFw, diamond represented by the following formula: 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 0 ≦ v ≦ 1.0 0 ≦ w ≦ 0.2 7. The combination according to claim 6, comprising at least one layer selected from a carbon-like film. 8. The diamond-like carbon film is made of CHxS
iyOzNvFw (provided that 0.05 ≦ x ≦ 0.7 0.01 ≦ y ≦ 3.0 0 ≦ z ≦ 1.00 ≦ v ≦ 1.00 ≦ w ≦ 0.2) Forming at least two layers of a film and a diamond-like carbon film represented by CHn (where 0.05 ≦ n ≦ 0.7), or continuously changing from one of these compositions to the other 7. The combination according to claim 6, wherein a layer is formed. 9. A method comprising: (a) a Group 5A metal (V, Nb, T) between a surface of a cam and a diamond-like carbon film formed on the surface of the cam;
a), a silicide or silicide containing at least one selected from Group 6A metals (Cr, Mo, W), Ti, and Zr; (b) Group 5A metals (V, Nb, T
a) a metal film mainly composed of at least one selected from a) and a Si film or a metal film mainly composed of Si formed thereon, or (c) a Group 5A metal (V, Nb, T
a) an intermediate layer composed of at least one metal film selected from Group 6A metals (Cr, Mo, W), Ti, and Zr and a silicon carbide film formed thereon, and a diamond-like carbon film. 9. The combination according to claim 6, wherein at least one layer is formed in this order.