JP2004324890A - Sliding device and faucet valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding device having stable sliding property with no irregular operating force by maintaining superior sliding property and wear resistance for a long period and using laser Raman spectroscopy for managing the crystal structure of an amorphous hard carbon film. <P>SOLUTION: The sliding device has a sliding member provided with the amorphous hard carbon film on the slide contact surface of at least one of two disc valve elements siding with each other. The amorphous hard carbon film has a Raman spectrum peak in a range of at least one of 1200-1400cm<SP>-1</SP>and 1500-1600cm<SP>-1</SP>in the laser Raman spectroscopy. The peak has a strength ratio to a flat portion being twice or more and the width of a 90% or more top portion of the peak having the maximum strength is 10cm<SP>-1</SP>or more. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding device used for a valve, a mechanical seal, a slider, and the like, and more particularly, to a forced valve used as a faucet or a hot and cold water mixing faucet.

  2. Description of the Related Art In a disk valve used for a water faucet, a hot water mixing faucet, or the like, a fluid passage formed in each valve body is opened and closed by sliding two disk-shaped valve bodies in a state of slidingly contacting each other. . For example, as shown in FIG. 2, a forced valve used as a faucet or a hot and cold water mixing faucet has a fixed valve body 30 and a movable valve body 20 which are in contact with each other at sliding contact surfaces 21 and 31. By operating the lever 40, the movable valve body 20 is moved to open and close the fluid passages 22, 32 formed in the valve bodies 20, 30 to adjust the flow rate of the supply fluid.

  The movable valve body 20 and the fixed valve body 30 are required to have high dimensional accuracy in order to maintain slidability and sealability, and are constantly rubbed with each other. Because of the exposure, the corrosion is severe. Therefore, in recent years, it has been possible to process the workpiece with high precision, and it has come to be formed of ceramics excellent in wear resistance and touch resistance.

  By the way, the sliding property and the sealing property are contradictory, and in order to enhance the sealing property, the sliding surface is made extremely smooth, and when a pair of valve bodies having these sliding surfaces are rubbed together, Linking (adhesion) occurs in which catching or abnormal noise occurs, and furthermore, the valve bodies stick to each other and do not move. Also, it has been known that the lever operation force gradually increases as the number of operations increases, even without reaching linking.

  Therefore, various solutions have been proposed to prevent this linking. For example, there is a valve body made of a porous ceramic having a three-dimensional network structure, in which resin or oil or the like is impregnated as a lubricant in the open pores (see Patent Documents 1 to 6).

In addition to those using such a liquid lubricant, Patent Document 7 discloses an invention relating to a “mechanical seal in which a diamond-like carbon thin film is formed on a sliding surface” as a device using a solid lubricant. Reference 8 discloses an invention relating to "a ceramic sliding portion structure having an amorphous diamond thin film formed thereon".
JP-A-61-206875 JP-A-61-244980 JP-A-62-4949 JP-A-62-37517 JP-A-62-37517 Japanese Patent Publication No. 5-50475 JP-A-1-261570 JP-A-3-223190

In the sliding member described in Patent Documents 1 to 6, in which a liquid lubricant is impregnated in porous ceramics having a three-dimensional network structure, engine oil, spindle oil, dynamo oil, turbine oil, fluorine-based oil, Silicone oil or the like is used. However, when this sliding member is applied to a faucet, a hot and cold water mixing faucet, etc., there is a high possibility that the above-mentioned lubricant is taken into a human body, and there is a problem that it may be harmful to the human body. Further, such a sliding member is difficult to manufacture, and has a disadvantage that the hardness of the sliding surface is low.

  On the other hand, sliding members coated with a so-called amorphous hard carbon film, such as amorphous diamond and synthetic pseudo-diamond disclosed in Patent Document 8 and the like, certainly improve the operating force and provide a light operating force. In some cases, it could be obtained, but the operating force varied, and the stability was lacking such that the operating force gradually increased during long-term use.

  This is because although it is clear that the amorphous hard carbon film is mainly composed of an amorphous structure, no more detailed internal structure is managed. In other words, since the evaluation of the internal structure of the amorphous hard carbon film, which has the greatest effect on the slidability, has not been established, a sliding member with an amorphous hard carbon film of various structures has been mixed with the product. Used, and this result naturally appeared as a variation in the slidability.

In view of the above problems, the present invention relates to a sliding device comprising an amorphous hard carbon film on at least one of the sliding surfaces of two sliding members that slide with each other. film has at least one of the range of the peak of the Raman spectrum 1200～1400Cm ^-1 and 1500～1600Cm ^-1 by laser Raman spectroscopy, the intensity ratio the peak for the flat portion is at least twice, and the peak A width of a top portion of 90% or more of the maximum strength of the sliding device is 10 cm ^-1 or more.

  In this case, the sliding member is formed of a valve body, and the flatness of the surface of the valve body is 3 μm or less, or the center line average roughness (Ra) of the valve body surface is 0.5 μm or less. Alternatively, a sliding device in which the thickness of the amorphous hard carbon film is 0.1 to 2.0 μm is preferable. In particular, a sliding device in which the valve body is made of a ceramic mainly containing alumina, zirconia, silicon nitride, silicon carbide, and aluminum nitride is preferable.

Further, in the forset valve having at least one sliding contact surface of two disc-shaped valve bodies sliding with each other, the amorphous hard carbon film is formed by laser Raman spectroscopy. located at least one of the range of the peak of the Raman spectrum 1200～1400Cm ^-1 and 1500～1600Cm ^-1 by law, the peak is at intensity ratio of 2 times or more with respect to the flat portion, and 90% of the maximum intensity in the peak A forset valve is provided, wherein the width of the top is 10 cm ^-1 or more.

  As described above, according to the present invention, a sliding device capable of maintaining excellent slidability and wear resistance over a long period of time can be obtained.

  Further, according to the present invention, by controlling the crystal structure of the amorphous hard carbon film by laser Raman spectroscopy, it is possible to maintain excellent sliding characteristics even when used for a long period of time. And a stable sliding device can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows only a valve element that constitutes a fawcet valve which is an example of the sliding member of the present invention. The movable valve body 20 is a disk-shaped body made of ceramics and has a fluid passage 22, and one surface is a sliding contact surface 21. The fixed valve body 30 is a disc-shaped body made of ceramics, has a fluid passage 32, and has an amorphous hard carbon film 34 formed on one surface as a sliding contact surface 31.

  With the fixed valve element 30 and the movable valve element 20 in contact with each other at the sliding surfaces 21 and 31, by moving the movable valve element 20, the fluid passages 22 and 32 provided in the respective valve elements are moved. And controls the opening and closing and adjustment of the supply fluid.

  At this time, since the sliding contact surface 31 of the fixed valve body 30 is made of the amorphous hard carbon film 34, the slidability and wear resistance are high, and the operating force of the movable valve body 20 by the lever can be reduced.

The material forming the fixed valve body 30 and the movable valve body 20 is a ceramic that is extremely hard and hard to deform, such as having a Young's modulus of 21000 to 45000 kg / mm ² and a Vickers hardness (Hv) of 1000 kg / mm ² or more. Specifically, ceramics mainly composed of alumina, zirconia, silicon nitride, silicon carbide, and aluminum nitride are most suitable.

For these raw materials, alumina or SiO ₂ or MgO for silicon nitride, oxides or nitrides of elements of the periodic table 2a or 3a for silicon nitride, and C, B, Al ₂ O ₃ for silicon carbide. For zirconia, Y ₂ O ₃ , CaO, MgO, CeO _2, etc. may be added and fired, and with substantial shrinkage of 3% or more, it becomes strong, robust, tough and wear-resistant. Excellent ceramics can be obtained. Then, the fixed valve body 30 may be polished on the sliding surface with the obtained ceramic, and then coated with the amorphous hard carbon film 34.

Here, the amorphous hard carbon film (alias: synthetic pseudo diamond thin film, diamond-like carbon, DLC, I-carbon) refers to a carbon film obtained by a thin film forming means such as a PVD method or a CVD method. Good sliding properties can be obtained due to its extremely low coefficient of friction. The amorphous hard carbon film also has a very high hardness such as a Vickers hardness (Hv) of 3000 to 5000 kg / mm ² .

  By the way, this amorphous hard carbon film is included as carbon (C) together with diamond and the like in terms of element, is close to graphite and amorphous carbon in terms of specific gravity, and is close to diamond in physical properties such as hardness. Has features. Therefore, classification by elemental analysis or measurement of specific gravity, hardness, insulating property, refractive index, and the like is considered to be difficult.

  According to the vapor phase synthesis method such as the CVD method and the PVD method, not only the amorphous hard carbon film, but also various crystalline carbons such as amorphous carbon and graphite, and even diamond can be formed. For this reason, there are drawbacks in that it is difficult to specify the obtained film and quality control is difficult.

  Therefore, in order to identify such a carbon film, an analysis method that is sensitive to the internal structure of the carbon film is required. In the present invention, laser spectroscopy is used. In other words, laser Raman spectroscopy is a method that can analyze the structure, crystallinity, etc. of a material in detail by measuring the Raman spectrum, and therefore, it is necessary to identify an amorphous hard carbon film having favorable characteristics. You can.

  The Raman spectrum is obtained by observing the following Raman scattered light. That is, when a sample is irradiated with laser light, the electron distribution of atoms and electrons is distorted due to the electric field of light, and the atoms and molecules are polarized. When this polarization is modulated by lattice vibrations and the like existing in the sample, the electron polarization has inelastic scattered light having a different frequency in addition to light having the same frequency as laser light (Rayleigh light). This is called Raman scattered light.

  As a result of various experiments performed by the present inventors, it was found that the peak of the Raman spectrum when the amorphous hard carbon film was analyzed by laser Raman spectroscopy should satisfy the following conditions. I found it.

That is, the chart of a preferred embodiment of a Raman spectrum of the amorphous hard carbon film of the present invention as shown in FIG. 3, the peak is present in at least one of the range of 1200～1400Cm ^-1 and 1500～1600Cm ^-1 In the peak having the highest intensity, the peak intensity IA has an intensity ratio IA / IB with respect to the intensity IB of the flat portion other than the peak that is twice or more, and the peak intensity IA is 90% or more of the maximum intensity IA at the peak. It is sufficient that the peak d has a broad peak such that the width d of the top is 10 cm ^-1 . The amorphous hard carbon film having such a broad peak shape can obtain extremely smooth slidability without peeling of the film during sliding.

FIG. 4 shows Raman spectra obtained by performing laser Raman spectroscopy on various carbon materials. As shown in FIG. 4 (a), an extremely sharp peak is observed at 1331 cm ⁻¹ in diamond, and FIG. 4 () is obtained in HOPG (Highly Oriented Pyrolytic Graphite) having a complete graphite structure (infinite planar ring structure). As shown in FIG. 4B, pyrolytic carbon (PG: Pyrolytic Graphite) having a single sharp peak near 1581 cm ^-1 and having a crystallite size of about 200 ° due to disordered graphite structure is shown in FIG. , A peak also appears at 1355 cm ⁻¹ .

Each of the peaks shown in FIG. 4 does not satisfy the conditions of the present invention in that they are extremely sharp peaks whose peak width, which is 90% or more of the maximum intensity, is smaller than 10 cm ⁻¹ . Therefore, when a carbon film exhibiting the Raman spectrum of graphite such as HOPG or PG or diamond is formed on the fixed valve body 30 made of ceramics and combined with the movable valve body 20 made of ceramics, the film is peeled off. Or the operating force is easily increased in a short period of time, and it becomes difficult to obtain the required slidability.

  In the sliding member of the present invention, the flatness of the surface of the base material on which the amorphous hard carbon film is formed is 3 μm or less, preferably 1 μm or less, and the surface roughness (center plug average roughness: Ra) is 0 μm. 0.5 μm or less is desirable. This is because when the flatness exceeds 3 μm or when the surface roughness (Ra) exceeds 0.5 μm, there is a risk of leakage. The thickness T of the amorphous hard carbon film is preferably in the range of 0.1 to 2.0 μm. This is because if the film thickness T is smaller than 0.1 μm, the film may be worn away due to long-term sliding, and if the film thickness T is larger than 2.0 μm, an enormous film formation time is required. This is because it is not practical.

Actually, when the film thickness T of the amorphous hard carbon film was variously changed, the manufacturability and the durability after the 100,000 times sliding test were evaluated. It can be seen that when the thickness T is in the range of 0.1 to 2.0 μm, both the manufacturability and the durability can be satisfied.

  In the above embodiment, the sliding member in which the amorphous hard carbon film 34 is formed on the fixed valve body 30 constituting the disk valve has been described, but the amorphous hard carbon film is formed on the movable valve body 20 side. Thus, the fixed valve body 30 side may be formed of ceramic alone. Alternatively, it is more preferable to form an amorphous hard carbon film on both the movable valve body 20 and the fixed valve body 30.

  Further, as the mating material that slides with the amorphous hard carbon film 34, the example in which sliding is performed with ceramics is described in the above embodiment, but a metal material, a resin material, or the like has a suitable sliding property as a mating material. Can be shown.

  Further, in the above embodiment, the example of the disk valve that slides between the flat surfaces is shown. However, the sliding device of the present invention may be applied to a sliding valve having a cylindrical or spherical sliding surface. it can.

  Therefore, the sliding device of the present invention can be used not only for disk valves but also for various applications such as ball valves and other various valve members, mechanical seals, bearings and sliders.

  Next, the result of an experiment will be described using the sliding device according to the present invention as an example of the forset valve shown in FIG.

The fixed valve body 30 constituting the fawset valve is made of alumina powder having a purity of 96% as a starting material, to which 0.5% by weight of SiO ₂ , 0.2% by weight of MgO and CaO are added, and a binder is further added. After stirring for 24 hours, the mixture was spray-dried to obtain an alumina granule having an average particle diameter of 3.7 μm. After the granules are formed into a disk shape by a die press, the granules are fired at a firing temperature of about 1600 ° C. in an oxidizing atmosphere, and are subjected to grinding and polishing to form an amorphous hard carbon film 34 on the surface. By coating, a fixed valve body 30 having a fluid passage 32 having a diameter of 5 mm, an outer diameter of 32 mm, a thickness of 5 mm, and a flatness of 1 μm or less was obtained.

The formation of the amorphous hard carbon film 34 on the fixed valve body 30 side was performed by the following method. That is, first, the fixed valve body 30 was attached to a substrate provided with a tungsten heater in a vacuum chamber reduced in pressure to about 10 Pa, and assembled in the chamber while introducing methane (CH ₄ ) gas and hydrogen (H ₂ ) gas. A microwave (frequency 2.45 GHz) is applied between the electrodes. Then, the methane gas is plasma-decomposed and deposited on the substrate on which the fixed valve body 30 is set, so that a film made of carbon (C) is obtained.

  By such a microwave plasma CVD method, a film of a carbon component can be obtained on the surface of the fixed valve body 30. Here, the temperature of the substrate heated by the tungsten heater is changed between room temperature and 800 ° C. By changing the film forming conditions over a wide range, such as changing the gas flow rate Q between 1 and 30 cc / min, or changing the degree of vacuum P between 0.01 and 6000 Pa, various carbon structures can be obtained. Was formed.

  Then, when the laser Raman spectroscopy analysis was performed on the carbon film thus obtained, as shown in FIGS. Eleven types of films 1 to 11 were obtained.

The measurement conditions of the laser Raman spectrometer at this time were a laser wavelength of 488 nm, a center wave number of 1400 cm ⁻¹ , an exposure time of 0.5 seconds, and an integration time of 100 times, but other than these conditions, around 1200 to 1600 cm ⁻¹ It does not matter if the Raman spectrum can be measured with high accuracy.

  On the other hand, when these carbon films were analyzed by other methods, elemental analysis using an X-ray microanalyzer showed that only carbon (C) was detected in any case, and that all films consisted of carbon components. I couldn't get it. Similarly, even using a specific gravity, electric resistance, hardness measuring device, X-ray diffraction or transmission electron microscope, it is possible to clearly identify the 11 types of carbon films classified by Raman spectrum as described above. Was impossible. Therefore, it was found that various types of carbon films can be more strictly analyzed by using the laser Raman spectroscopy.

In the 11 types of Raman spectra obtained by laser Raman spectroscopy shown in FIGS. No. ^{1 in} which a sharp peak is observed at 1331 cm ⁻¹ is diamond. No. 2 shows a single sharp peak near 1581 cm ^−1, which is HOPG (Highly Oriented Pyrolytic Graphite) having a complete graphite structure (infinite planar ring structure). It is known that those exhibiting sharp peaks at 1581 and 1355 cm ^-1 of No. 3 are pyrolytic carbon (PG), but a clear view has been obtained to date on other film structure analyses. Absent.

  However, even if the material name cannot be specified, the carbon film is non-destructive, non-contact, can be measured immediately on the spot, and has high resolution, if laser Raman spectroscopy is used. Therefore, it can be seen that the product evaluation by laser Raman spectroscopy can be an indispensable evaluation method for quality maintenance if a correlation with the product characteristics such as slidability is obtained and an ideal quality control system can be established.

  On the other hand, the movable valve body 20 is composed of the same alumina ceramic alone as the fixed valve body 30, has a fluid passage 22 having a diameter of 5 mm, an outer diameter of 25 mm, a thickness of 7 mm, and a flatness of the sliding contact surface 21 of 1 μm or less. .

Then, as shown in FIG. The fixed valve body 30 provided with the various carbon films 1 to 11 is set in the water faucet while being pressed by the casing with an axial force of 30 kgf so that the sliding surfaces 21 and 31 slide with each other. Injection was performed at a pressure of cm ^{2, and} a forset valve capable of controlling the amount of hot water by operating the lever 40 was manufactured.

  A test in which the movable valve body 20 is slid by the lever 40 is performed 200,000 times with respect to such a forset valve, and thereafter, the pressing force of the lever 40 required for sliding the movable valve body 20 is determined by a push-pull gauge. And the operating force.

The results are as shown in Table 2. From this result, it was found that No. 1 consisting of diamond, HOPG and PG In the case of the one provided with 1 to 3 carbon films, the peak width, which is a range of 90% or more of the maximum intensity of the peak, is a sharp peak of less than 10 cm ^−1, which is a standard of smooth operating force. The slidability of 6 kg or less could not be satisfied for a long time of 200,000 times or more.

  No. The peak positions of the carbon films of Nos. 4 and 5 were not within the range of the present invention, and were sharp peaks. Since the ratio of the maximum intensity of the peak to the flat portion of the carbon films Nos. 6 to 8 was less than twice, the slidability of 0.6 kg or less could not be satisfied for 200,000 times or more for a long time.

On the other hand, No. 1 of the embodiment of the present invention. Carbon film of 9-11, the peak of the Raman spectrum is in at least one of the range of 1200～1400Cm ^-1 and 1500～1600Cm ^-1, and the intensity ratio flat portion of the peaks 2 times or more, and the maximum peak Since the peak width, which is a range of 90% or more of the strength, has a broad peak shape of 10 cm ^-1 or more, the slidability of 0.6 kg or less can be satisfied for 200,000 times or more for a long period of time. Was.

3A and 3B show only a valve element of a force-set valve using the sliding member of the present invention, wherein FIG. 4A is a perspective view, and FIG. 4B is a cross-sectional view taken along line XX in FIG. It is a schematic perspective view which shows a general forceet valve. FIG. 4 is a chart showing a Raman spectrum of an amorphous hard carbon film in the sliding member of the present invention. FIG. 4 is a chart showing a Raman spectrum of a carbon film as a comparative example. FIG. 3 is a chart showing Raman spectra of various carbon films. FIG. 3 is a chart showing Raman spectra of various carbon films. FIG. 3 is a chart showing Raman spectra of various carbon films. FIG. 3 is a chart showing Raman spectra of various carbon films.

Explanation of reference numerals

20: movable valve element 30: fixed valve element 21, 31: sliding contact surface 22, 32: fluid passage 34: amorphous hard carbon film

Claims (6)

In a sliding device comprising an amorphous hard carbon film on at least one sliding contact surface of two sliding members sliding with each other, the amorphous hard carbon film has a peak of Raman spectrum by laser Raman spectroscopy. There is in at least one of the range of 1200～1400Cm ^-1 and 1500～1600Cm ^-1, the peak is at intensity ratio of 2 times or more with respect to the flat portion, and the width of more than 90% of the top of the maximum intensity in the peak A sliding device characterized by being 10 cm ^-1 or more. The sliding device according to claim 1, wherein the sliding member is formed of a valve body, and a flatness of a surface of the valve body is set to 3 µm or less. The sliding device according to claim 2, wherein the center line average roughness (Ra) of the surface of the valve body is 0.5 m or less. 4. The sliding device according to claim 2, wherein the thickness of the amorphous hard carbon film is 0.1 to 2.0 [mu] m. The sliding device according to any one of claims 1 to 4, wherein the valve body is made of a ceramic mainly containing alumina, zirconia, silicon nitride, silicon carbide, and aluminum nitride. In a foset valve comprising an amorphous hard carbon film on at least one sliding contact surface of two disc-shaped valve bodies sliding with each other, the amorphous hard carbon film is formed by laser Raman spectroscopy. located at least one of the range of the Raman spectrum of the peak 1200～1400Cm ^-1 and 1500～1600Cm ^-1, the peak is at intensity ratio of 2 times or more with respect to the flat portion, and more than 90% of the maximum intensity in the peak A forset valve, wherein the width of the top is 10 cm ^-1 or more.

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