JPS6116867B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a mechanical seal formed between a fixed part and a rotary shaft that is freely rotatable with respect to the fixed part, and more specifically, a mechanical seal formed in a shaft sealing part of a rotating shaft of a compressor, particularly the shaft of a rotating shaft of a swash plate type compressor for a car cooler. This invention relates to a mechanical seal formed in a sealing part. A mechanical seal formed between such a fixed part and a rotating shaft is generally fixed airtightly to the fixed part side, and is airtightly connected to a fixed piece arranged with a slight gap between the fixed part and the rotating shaft side. The rotating piece is rotated together with the rotating shaft, and the rotating piece is slid in pressure contact with the fixed piece to prevent leakage of gas or liquid. Further, the fixed piece is formed into an annular member (seat ring) that is fixed to the fixed member, the rotating shaft is disposed in the center hole of the fixed piece, and the rotating piece is connected to the rotating shaft via an airtight member that is airtightly attached to the rotating shaft. The rotating piece is formed into an annular ring (driven ring or rotating ring) that is loosely attached to the rotating shaft through its center hole, and ridges are formed on one surface of the rotating piece due to the elasticity of the spring attached to the rotating shaft. A common configuration is such that a protruding annular sealing surface is slid into pressure contact with one surface of the fixed piece. Mechanical seals with the above configuration require wear resistance and strength for the fixed piece and the rotating piece (driven ring), so fired carbon, a composite material of synthetic resin and carbon, etc. are used for the rotating piece, while the fixed piece (Seat ring) includes stellite, stainless steel,
High-silicon cast iron is generally used. In car cooler compressors such as swash plate type compressors, rotary type compressors, and reciprocating type compressors, gaseous refrigerant is compressed and discharged, condensed in a condenser, and vaporized and expanded in an evaporator. Compression is performed within a closed circuit that draws air into the air. To explain the swash plate type compressor in more detail, the lubricating oil is atomized within the compressor housing and is sent together with the refrigerant to parts that require lubrication, such as between the piston and the cylinder, between the swash plate and the piston shoe, etc. However, if there is a large amount of lubricating oil, it will circulate together with the compressed refrigerant through a closed circuit that includes the condenser and evaporator, impairing the cooling efficiency of the cooler, so it is extremely difficult to completely separate the lubricating oil from the refrigerant. There is a need to separate the oil from the refrigerant or reduce the amount of lubricating oil, and there is also a need to make the compressor itself smaller and lighter so that it can be mounted on a vehicle, so there are compressors that do not include an oil pump. Furthermore, since compressors for car coolers are driven by internal combustion engines, they are unsteady over a wide range of revolutions, from 500 revolutions per minute when the engine is idling to 6,500 revolutions per minute when driving at high speeds or accelerating suddenly. The operating conditions of compressors for car coolers are subject to many fluctuations, such as not only being driven during a period of time, but also being started even when the compressor is not sufficiently lubricated when the vehicle starts running after being stopped for a long time. In addition, between the compressor piston and cylinder, between the swash plate and the piston shoe, etc., when the piston starts to reciprocate due to the swash plate, a forming phenomenon occurs in the oil stored in the oil reservoir that communicates with the low pressure side in the compressor. (a phenomenon in which the refrigerant dissolved in the oil vaporizes due to a sudden pressure drop and the entire oil bubbles), lubricating oil is immediately supplied, but the shaft attached to the shaft seal of the compressor rotating shaft Supplying lubricating oil to the sliding parts of the sealing device (mechanical seal) becomes extremely difficult as the amount of lubricating oil is reduced, and the operating conditions of the mechanical seal of the shaft sealing part become severe, and the sliding parts of the mechanical seal are Lubrication by a mist mixture of lubricating oil and refrigerant gas sealed in the refrigeration circuit containing the refrigeration circuit is insufficient.
This is an operating condition in which solid contact rotational sliding without lubricating oil intervening on the sliding surface also occurs. For example, after the compressor starts operating, it takes several tens of seconds for the refrigerant in the external pipe to return to the compressor.If the car is not in use for a long time, the oil adhering to the sliding parts may fall and be removed for several tens of seconds. Situations may occur where the device is slid and rotated for even minutes without a supply of lubricating oil. The fixing piece (seat ring) of the mechanical seal of the shaft seal of such a swash plate type compressor for a car cooler is mainly made of normal cast iron such as gray cast iron (FC20), special cast iron with even and finely distributed graphite, or ceramic material. However, the cast iron fixing pieces generally had a hardness of Hv300 or less and suffered from a lot of wear, and part of the graphite dispersed in the sealing material fell off during surface processing, causing surface defects. As a result, as the seal wears out, the roughness of the sliding surface of the seal loses its uniformity, and the sealing performance deteriorates. Ceramic seals are also susceptible to thermal shock, especially during startup, where the temperature rises due to frictional heat until the refrigerant returns from the suction side external pipe, and then the return refrigerant flows into the compressor and reaches a relatively low temperature. There is a risk that the refrigerant will cause the material to cool rapidly, resulting in cracking. In view of the above-mentioned known technology, the present inventors first made a fixing piece (seat ring) to be attached to the fixing part from iron-based material, and coated the surface with Hv400 or more, preferably
He proposed forming a high-hardness layer with a hardness of Hv800 or higher and making the rotating piece attached to the rotating shaft from a carbonaceous material (Japanese Patent Application No. 145990-1989, filed on November 13, 1978). The above-mentioned high hardness layer can be obtained by making the fixed piece from carbon steel or low alloy steel, by surface-treating the fixed piece base material of steel material by soft nitriding treatment, boron soaking treatment, quenching treatment, or by applying hard chrome plating. It is formed as a result. In the mechanical seal proposed above,
Used in swash plate compressors for car coolers that do not require an oil pump, the airtightness of the seal sliding surface is less likely to be compromised, and the amount of leakage of refrigerant gas and lubricating oil is reduced compared to when using conventional mechanical seals. I found that it was reduced by half. As a result of further developing the research related to the above proposal, the present inventors have developed a mechanical seal in which one of the sliding surfaces of the mechanical seal is coated with a porous plating layer of chromium, which makes the surface porous. When the other side is made of carbonaceous material, the friction coefficient and amount of wear on the sliding surface are significantly lower than those using the fixed piece (seat ring) formed with the above-mentioned high hardness layer. It has been discovered that a mechanical seal can be provided that does not cause stecking on the moving surface, has good sealing performance, and is more durable. That is, based on the invention of Japanese Patent Application No. 54-145990, a hard chrome plating layer was selected as the high hardness layer, and a fixed piece was applied to one side of a base material made of general structural rolled steel SS41 as a comparison material. The friction coefficient and amount of wear were compared using a thrust tester using a fixed piece made of the same steel material with a chromium porous plating layer applied on one side as a test piece.
The rotating piece was made of gray cast iron (FC20), and 60% graphite powder by weight.
Two types were used that were molded from a mixed material of 30% phenolic resin and 10% silicon dioxide powder. The thrust tester is made by molding a stationary piece into a cylindrical shape with an outer diameter of 30 mm and an inner diameter of 16 mm, applying a plating layer to the annular surface and fixing it to a base with the plating layer on the top surface, while the rotating piece is made of the above-mentioned material. The rotary piece was formed into a cylindrical shape with an outer diameter of 24 mm and an inner diameter of 20 mm, and this rotating piece was placed on the top surface of the plating layer coaxially with the fixed piece, and 5 mm was formed in the axial direction of both cylinders.
A load of Kg/cm ² was applied, and the rotating piece was slid and rotated at 2000 revolutions per minute (average sliding speed 2.3 m/sec) without lubrication. The chrome plating surface roughness of the fixed piece was 0.1 μmRz, the surface roughness of the gray cast iron rotating piece was 0.7 μmRz, and the surface roughness of the carbon molded rotating piece was 0.4 μmRz. The combinations of fixed piece and rotating piece in the above test are as shown in Table 1, the measurement results of the friction coefficient in these combinations are shown in Fig. 1, and the measurement results of the amount of wear are shown in Fig. 2. , a combination of a stationary piece with a chromium porous plating layer and a rotating piece of carbon molded body (symbol D in Figures 1 and 2).
It was found that the friction coefficient (represented by ) is extremely small, approximately 0.1 or less, and the specific wear amount of the plating layer of the stationary piece is extremely small, and the specific wear amount of the rotating piece is also the lowest. In the bar graph of FIG. 2, the hatched bar graph represents the rotating piece, and the unshaded bar graph represents the plating layer of the fixed piece.

[Table] Based on the above test results and the examples described below, the inventors of the present invention achieved the following by making one of the sliding surfaces of the mechanical seal a porous plating layer of chromium and the other one made of a carbonaceous material. This provides a mechanical seal that has better sealing performance and is more durable than mechanical seals that combine a high-hardness layer of chromium and a carbonaceous material. The present invention includes a fixing piece attached to a fixing part;
A rotary piece is attached to a rotatable shaft of the fixed part and rotated together with the rotary shaft, and the rotary piece is slidably pressed against one surface of the fixed piece to maintain airtightness of the sliding rotary part. In this mechanical seal, one of the fixed piece and the rotating piece has a porous plating layer of chromium on its contact sliding surface, and the other is made of carbonaceous material. By doing so, even if the supply of lubricating oil is not sufficient and a rotating and sliding state of solid contact occurs,
The object of the present invention is to provide a mechanical seal that has low sliding resistance, does not cause uneven wear, is therefore durable, and has low gas and oil leakage. In addition, the present invention provides a compressor for a car cooler that does not include an oil pump, by applying a chromium porous plating layer to the contact sliding surface of the fixed piece and making the rotating piece carbonaceous, thereby preventing leakage of refrigerant gas or lubricating oil. The purpose of the present invention is to provide a mechanical seal that significantly reduces the amount of damage compared to conventional ones. The porous plating layer of chromium used in the mechanical seal of the present invention is made by making the plating surface of chrome porous in a polka dot or mesh pattern. It is formed by a known method such as a mechanical processing method, which will be discussed later, or an electrolytic etching method, in which a material is plated with chrome and then etched to form holes and grooves. There are three types of electrolytic etching methods: channel type, pinpoint type, and intermediate type.The electrodeposition conditions for chrome plating are essentially the same as those for normal industrial chrome plating, but the channel type requires a plating bath temperature of 60°C. ℃, the pinpoint type can be obtained at a bath temperature of 50℃, and the intermediate type can be obtained at an intermediate temperature.For both types, the workpiece is prepared in a bath similar to the plating solution (a plating bath may be used). as the anode and the anode current density is 30 to 60A/dm ²
When electrolyzed, holes and grooves are formed. For this etching, 1 to 2% sulfuric acid may be used. When etching is performed using phosphoric acid, the surface is polished to a smooth surface at the same time as grooves are formed, and arbitrary pores are formed to create a porous pattern with polka dots. It is known to perform etching with a screen attached. In addition, by honing after etching,
It is also known that porosity adjustment can be made. In the present invention, carbonaceous materials include those formed by molding carbon and/or graphite powder, those formed by kneading carbon and/or graphite powder with synthetic resin, and condensing the synthetic resin, or those formed by condensing the synthetic resin. Other materials consisting of carbon and/or graphite shall be included. Graphite also includes carbonaceous substances that are not completely graphitized. In the mechanical seal of the present invention, it is practical to apply a chromium porous plating layer to the stationary piece and to make the rotating piece from a carbonaceous material. The chromium porous plating layer has pores that appear on its surface with a diameter of 5 to 20 μm, a number of pores that appear on the surface of 500 to 2,000 per square mm, and a hardness of mHv800 to 2000.
1100. The size of the hole is expressed by the diameter of a circle having the same area as the planar area of the hole, and there is no problem as long as holes of the above size and number appear in approximately 80% of the area of the required sliding portion. Further, even if the holes are larger than the above size, there is no problem as long as the total area is 20% or less. Further, the size and number of the holes can be practically used even if the upper and lower limits are slightly exceeded depending on the object to be sealed and the conditions to which the mechanical seal is applied. The thickness of the chromium porous plating layer described above varies depending on the object for which the mechanical seal is used and the usage conditions of the mechanical seal, but it is practical if it is approximately 5 to 200 μm, and 5 μm.
If the thickness is less than 200 μm, durability will deteriorate, and if the thickness is 200 μm or more, it is excessive. It is preferable to polish the surface of the chromium porous plating layer by lap polishing, and the surface roughness is
It is preferably 0.1 μmRz or less. The carbonaceous material constituting the other sliding surface of the mechanical seal of the present invention may be formed by firing carbon and/or graphite powder, or a material consisting essentially of carbon and/or graphite. However, a kneaded molded product of carbon and/or graphite powder and synthetic resin is easy to mold, inexpensive, and practical. The kneaded molded product of carbon and/or graphite powder and synthetic resin has a particle size of 300μm in weight%.
Less than 30-80% of carbon and/or graphite powder
and the remaining part are mixed with one type of resin selected from phenol resin, epoxy resin, furan resin, polyimide resin, etc., and molded to cure (condense) the resin. If the particle size of carbon and/or graphite powder is 300 μm or more, it is difficult to mold it, and the smaller the particle, the better the durability, but it is practically preferable that the particle size is 100 μm or less, and further within this range. Also, it is preferable to use a mixture of large and small particle sizes. Moreover, it is preferable to use relatively hard graphite as a main component of the powder. If the amount of carbon and/or graphite powder is less than 30%, the frictional resistance will be large, and if it is more than 80%, the strength will be insufficient. Its preferred range is 40-70%. In addition, when molding the above-mentioned kneaded molded product, 2 to 15% by weight of additive powder of material with low frictional resistance, such as powder of one or more of silicon dioxide, silicate, boron nitride, etc. % mixing is preferable for reducing the frictional resistance of the kneaded molded product. In this case, the amount of the synthetic resin is 15 to 45% by weight. The particle size of the additive powder is 50 μm or less. Particle size is 50
If it exceeds .mu.m, the wear of the mating material that rubs against it and the kneaded molded product itself will be greater than when no additive is added. If the amount of additive powder is less than 2%, the addition of the additive has almost no effect, and if it exceeds 15%, it increases the wear of the mating material on which friction slides. The amount of additive powder added is preferably 5 to 10%. If the amount of synthetic resin mixed with the additives is less than 15% by weight, the strength will be insufficient, and 45
% or more, the friction reduction becomes large. The preferred amount of synthetic resin is 20-30%. The above particle size is the diameter of a spherical body having the same volume as the particle. Furthermore, the mechanical seal of the present invention is
As a general usage condition, the PV value is approximately P: 30
Kg/cm ² ×V: It is preferable to use the limit at 8 m/s. The embodiment of the present invention described below is applied to a mechanical seal for sealing the leakage of refrigerant gas and lubricating oil in the shaft seal portion of a swash plate type compressor for a car cooler. Prior to describing the embodiments, a swash plate compressor 10 for a car cooler will be described with reference to FIG. 3, and a mechanical seal used in the compressor will be described with reference to FIGS. 4 and 5. The swash plate compressor consists of a cylinder block 2 in which a plurality of cylinder pores 1 are formed, cylinder heads 3 and 4 that close both sides of the cylinder block 2, a piston 21 disposed inside the cylinder pore 1, the cylinder block 2 and the cylinder heads 3 and 4. valve seats 5 and 6 interposed between the piston 2;
The mechanical seal 30 has a shaft hole 7 formed in the cylinder head 3 and a shaft hole 7 formed in the cylinder head 3 in the shaft sealing part. provided between. The piston 21 has a cylindrical shape as a whole, and a swash plate 22 is placed in a recess 23 formed in the center of the piston 21.
A shoe 24 is disposed in sliding contact with the swash plate 22, and a ball 25 is disposed between the shoe 24 and the piston 21. The swing of the swash plate 22, which rotates together with the rotating shaft 20, causes the inside of the cylinder pore 1 to be The refrigerant gas is sucked into the cylinder pore 1 from the suction chambers 11 and 12 formed between the cylinder head 3 and the valve plate 5 and between the cylinder head 4 and the valve plate 6, and is compressed. The exhaust gas is discharged into exhaust chambers 13 and 14 formed between the cylinder head 4 and the valve plate 5 and between the cylinder head 4 and the valve plate 6. That is, the swash plate type compressor 10 sucks refrigerant gas, which has been circulated in the refrigeration circuit and returned to the compressor, into the cylinder pore 1 from the suction chambers 11 and 12, compresses it with the piston 21, and then transfers it to the exhaust chamber 13,
14 to the condenser, where it is cooled and liquefied, and then sent to the evaporator where it is evaporated.The latent heat of vaporization is taken from the surroundings to cool the surrounding air.The evaporated refrigerant gas is returned from the suction chambers 11 and 12 to the cylinder pore 1. It performs an operation cycle that draws air into the body. A small amount of lubricating oil is sealed in the oil reservoir chamber 8 in the cylinder block 2 or in the crank chamber 9 of the swash plate 22 at the time of assembly, and the lubricating oil is mixed with the refrigerant gas flowing as the swash plate 22 swings in the crank chamber 9. The bearings 27, 27 between the cylinder block 2 and the rotating shaft 20, and the cylinder block 2 and the swash plate 2
It is supplied to the bearings 28, 28 between the two boss parts 26, or the pores 29, 29 of the valve seats 5, 6.
29 together with refrigerant gas. Although it is not clear in the drawing, the oil reservoir chamber 8 and the crank chamber 9 are communicated with the low pressure side (suction side) of the compressor. The mechanical seal 30 is provided at the end of the cylinder head 3 in the shaft hole 7 to prevent leakage of refrigerant gas and lubricating oil from the compressor body, so the flow of refrigerant gas is small near the mechanical seal 30. , therefore it is difficult to supply lubricating oil. The seat ring (fixed piece) 31 of the mechanical seal 30 is fitted into the shaft hole 7 of the cylinder head 3, and tightly sealed against the shaft hole 7 by the O-ring 32 fitted to the seat ring (fixed piece) 31. Seal. On the other hand, a packing 33 having a U-shaped cross section and opening diametrically outward is pressed against the outer periphery of the rotating shaft 20 at its inner periphery.
Annular washers 34 and 3 are provided in a U-shaped cross section, respectively.
5, and insert spring 3 between both washers 34 and 35.
6, is fixed to the rotating shaft 20, and has a leg piece long enough to cover the packing 33.
one end of the spring 36 is elastically supported on the bottom surface of the
The other end of the spring 36 presses the end edge of the packing 33 through the washer 34 against one surface of the rotating ring (rotating piece) 38 of the mechanical seal, so that the end surface of the rotating ring (rotating piece) 38 is pressed against the seat ring. (Fixed piece) Pressed against the end face of 31. forming a protrusion 39 on the free end of the leg piece of the support body 37;
By engaging the protrusion 39 with a recess 41 formed on the outer periphery of the rotating ring (rotating piece) 38, the rotating ring (rotating piece) 38 is caused to follow the rotating shaft 20. The seat ring (fixed piece) 31 and the rotating ring (rotating piece) 38 are both formed in an annular shape, and the rotating shaft 20 is loosely inserted into the inner hole of the seat ring (fixed piece) 38. An annular protruding ridge 42 formed in a circular shape is brought into pressure contact with the end surface of the seat ring (fixed piece) 31. The rotating ring (rotating piece) 38 is formed of a carbonaceous material, and the surface of the seat ring (fixed piece) 31 on the side to which the rotating ring (rotating piece) 38 is pressed by the elasticity of the spring 36 is coated with a chromium porous plating layer. 4
By applying 0, it is difficult to supply lubricating oil, and in some cases, the mechanical seal of the swash plate type compressor is rotated without lubricating oil, compared to the mechanical seal used conventionally. The amount of oil leakage is reduced to less than half, and even compared to the mechanical seal made of a combination of a high hardness layer and carbonaceous material that the present inventors proposed earlier, the amount of oil leakage is reduced during long-term use, and the following are achieved. The durability has been improved as will be explained with reference to the embodiment. Example 1 A base material for the seat ring (fixing piece) of a mechanical seal was manufactured from general structural rolled steel material SS41, and after forming unevenness by shot blasting on the surface by dents with a surface roughness of 5 to 15 Rz, the base material was 250g of chromic anhydride and sulfuric acid per 1 piece of wood.
Immerse in a sergeant bath containing 2.5gr, bath temperature 50
Chrome plating was applied at a temperature of ±2° C. and a current density of 20 A/dm ₂ to obtain a plating thickness of approximately 50 μm, and the surface was lap-polished to obtain a fixed piece. Its surface roughness is
It was 0.1μmRz. The rotating ring (rotating piece) of the mechanical seal is made of a mixture of 60% graphite powder with a particle size of 100 μm or less, 10% silicon dioxide powder with a particle size of 50 μm or less, and the balance phenol resin. Knead, form into a ring, and heat to 350°C at 170°C.
Heat molded for 3 minutes under pressure of Kg/ ^cm2 , then 190
The synthetic resin is cured (condensed) by heating at ℃ for 12 hours. Its surface roughness is 0.4μmRz
It was hot. When the coefficient of friction between the rotating piece and the fixed piece was measured using the thrust tester, it was found to be 0.07 to 0.1μ.
(See Figure 1D). The above-mentioned fixed piece and rotating piece are used as the seat ring and rotating ring of a mechanical seal of a swash plate compressor with a displacement of 148 c.c., and the annular ridge of the rotating piece is pressed into contact with the chromium porous plating layer of the fixed piece. We then conducted a durability test. At this time, 1.4 kg of Freon R12 (trade name) was filled as a refrigerant in the refrigeration circuit including the compressor, and 180 c.c. of refrigeration oil was filled as a lubricating oil, and the rotation speed was 4500 rpm.
It was operated continuously for 150 hours. During the test, the sliding speed of the fixed piece and rotating piece was 5.2 m/s, and the pressing force was 5.
Kg/cm ² , the gas pressure on the discharge side of the compressor is 25 Kg/cm ² , and the gas pressure on the suction side is 2 Kg/cm ² , and lubrication is provided by a mist of refrigerator oil and refrigerant gas. was observed. As a result of the above continuous operation durability test, the specific wear amount of the porous plating layer of the fixed piece was 0.5×10 ^-5 mm ³ /mKg
The specific wear amount of the carbonaceous molded product of the rotating piece is 0.6.
×10 ^-5 mm ³ /mKg. Example 2 The same seat ring (fixed piece) of a mechanical seal as used in Example 1 was used, and the rotating ring (rotating piece) was made with a particle size of
80% graphite powder with particle size of 100μm or less
A mixture of 2% silicate powder with a diameter of 50 μm or less and the balance epoxy resin was kneaded to produce 350 kg/kg at 170°C.
A mechanical seal similar to that in Example 1 was constructed using a material that was heat-molded for 3 minutes under a pressure of cm ² and then heated at a temperature of 190° C. for 12 hours to harden the resin. The friction coefficient μ of the combination of the two was 0.08 to 0.1 using a thrust tester. As a result of a continuous operation durability test similar to that in Example 1 using a swash plate compressor incorporating the mechanical seal described above, the specific wear amount of the porous plating layer of the fixed piece was 0.6×10 ^-5 mm ² /mKg, and that of the rotating piece. The specific wear amount of the carbonaceous molded product was 2.3×10 ⁻⁵ mm ³ /mKg. Example 3 A base material for a seat ring (fixing piece) of a mechanical seal was manufactured from S45C, a general structural rolled steel material. The surface roughness of the base material was 0.1 μmRz.
A 120 μm chrome plating layer was formed on this base material under the same conditions as in Example 1, and the base material was etched for 2 to 5 minutes at an anode current density of 45 A/dm ² in a bath with the same composition as the plating bath. A porous plating layer of chromium was formed on the surface of the base material by surface lap polishing. Its surface roughness was 0.1 μm. The rotating ring (rotating piece) of the mechanical seal was formed by kneading 30% graphite powder with a particle size of 100 μm or less in weight percent and 70% polyimide resin, molding it, and curing the resin. . The coefficient of friction μ between the fixed piece and the rotating piece was measured using a thrust tester and was found to be 0.1 to 0.12. The fixed piece and rotating piece constitute a mechanical seal for a swash plate compressor in the same manner as in Example 1,
When a continuous operation durability test was conducted under the same conditions as in Example 1, the specific wear amount of the porous plating layer of the stationary piece was 1.2×10 ^-5 mm ³ /mKg, which was the same as that of the carbonaceous molded product of the rotating piece. The amount was 5.2×10 ⁻⁵ mm ³ /mKg. Example 4 The seat ring (fixed piece) of the mechanical seal was the same as in Example 3, and the rotating ring (rotating piece) had a particle size of 100% by weight.
A mixture of 50% graphite powder with a particle size of 50 μm or less, 15% silicon dioxide and boron nitride powder with a particle size of 50 μm or less as additives, and the remainder furan resin is kneaded and molded to cure the resin. there was. The coefficient of friction μ between the porous plating layer of the stationary piece and the rotating piece is 0.08~ as measured by a thrust tester.
It was 0.11. A mechanical seal for a swash plate compressor was constructed in the same manner as in Example 1 using the above-mentioned fixed piece and rotating piece, and as a result of a continuous operation durability test under the same conditions as in Example 1, the specific wear of the porous plating layer of the fixed piece was The amount of wear was 1.0×1.0 ⁻⁵ mm ³ /mKg, and the specific wear amount of the carbonaceous molded product of the rotating piece was 1.0×10 ⁻⁵ mm ³ /mKg. Example 5 The same seat ring (fixed piece) of the mechanical seal as used in Example 1 was used, and the rotating ring (rotating piece) was made of graphite powder with a particle size of 100 μm or less 60% by weight. A mixture of 7% silicon dioxide, silicate, and boron nitride powder with a particle size of 50 μm or less, and the balance phenol resin was kneaded and molded to cure the resin. The coefficient of friction between the porous plating layer of the fixed piece and the rotating piece was 0.07 as measured with a thrust tester.
It was ~0.1. A mechanical seal similar to that in Example 1 was constructed using the above fixed piece and rotating piece, and a continuous operation durability test was conducted under the same conditions as in Example 1. As a result, the specific wear amount of the porous plating layer of the fixed piece was 0.8. ×10 ^-5 mm ³ /m
Kg, and the specific wear amount of the carbonaceous molded product of the rotating piece is
It was 0.7×10 ^-5 mm ³ /mKg. Comparative Example 1 A combination of the stationary piece of Example 1 and a rotating piece made of gray cast iron material FC20 with a surface roughness of 0.7 μm had a friction coefficient of 0.33 to 0.37 (Fig. 1B).
), the results of a continuous operation test conducted under the same conditions as in Example 1 using a mechanical seal composed of both of them showed that the specific wear amount of the fixed piece was 50 × 10 ^-5 mm ³ /mKg.
The specific wear amount of the rotating piece is 80×10 ^-5 mm ³ /mKg
It was hot. Comparative example 2 Using the same fixing piece as in Example 2, the surface roughness was
A combination of rotating pieces made of general cast iron material SUP6 with 0.7μmRz has a friction coefficient of 0.31 to 0.34, and when the same test as in Example 1 was conducted using a mechanical seal made of both, the fixed piece The specific wear amount of the rotating piece was 35×10 ⁻⁵ mm ² /mKg, and the specific wear amount of the rotating piece was 40×10 ⁻⁵ mm ³ /mKg. Comparative Example 3 A seat ring (fixing piece) of a mechanical seal was used in which the base material was made of general structural steel SS41 and an industrial chrome plating layer was formed on its surface. Its surface roughness was 0.1 μm. A mechanical seal was constructed using the same carbonaceous molded product as in Example 1 as a rotating ring (rotating piece). The friction coefficient of both was measured with a thrust tester and was 0.15 to 0.25 (see Figure 1 C). When the same test as in Example 1 was conducted using the above mechanical seal, the ratio of the chrome plating layer of the fixed piece was The wear amount was 5.0×10 ⁻⁵ mm ³ /mKg, and the specific wear amount of the carbonaceous molded product of the rotating piece was 7.0×10 ⁻⁵ mm ³ /mKg. Comparative Example 4 A mechanical seal was constructed by using the same fixed piece as in Comparative Example 3 and combining the same rotating piece as in Comparative Example 1. The coefficient of friction between the fixed piece and rotating piece is 0.4 to 0.45
(See Fig. 1A) When continuous operation was performed using the above mechanical seal under the same conditions as in Example 1, the specific wear amount of the chrome plating layer of the fixed piece was
162×10 ^-5 mm ³ /mKg, specific wear amount of rotating piece is 88×
It was 10 ^-5 mm ³ /mKg. Comparative Example 5 A mechanical seal was constructed with the same fixed piece as in Comparative Example 3 and the same rotating piece as in Comparative Example 2. The coefficient of friction between the chrome plating layer of the fixed piece and the rotating piece is 0.35~
0.4, and when continuous operation was performed using the above mechanical seal under the same conditions as in Example 1, the specific wear amount of the chrome plating layer of the fixed piece was 100 × 10 ^-5 mm.
³ /mKg, specific wear amount of rotating piece is 60×10 ^-5 mm ³ /m
It was Kg. The test data of the above examples and comparative examples are summarized in Table 2, and the mechanical seal of the present invention is a mechanical seal consisting of a fixed piece on which an industrial chrome plating layer is formed and a rotating piece made of cast iron. The specific wear amount is significantly smaller than that of the mechanical seal proposed by the present inventors, which combines a stationary piece with an industrial chrome plating layer and a rotating piece made of a carbonaceous molded product. It is known that the amount has been greatly improved.

【table】

【table】

【table】

[Table] Also, during the continuous operation durability test in each embodiment of the present invention, the amount of lubricating oil leaking from the mechanical seal gradually increased almost linearly with time, but after 150
Even with the passage of time, the amount remains at approximately 5 mg, and its gradual increase trend remains unchanged. In FIG. 6, line E shows the amount of oil leakage in Example 1 in comparison with the test time. However, in a mechanical seal in which a high-hardness layer formed by industrial chrome plating is formed on the stationary piece, even in Comparative Example 3 in which a carbonaceous molded product is used for the rotating piece, lubricating oil The amount of oil leaked was slightly larger than that of the embodiment of the present invention, and after 100 hours of continuous operation, the amount of oil leaked rapidly increased and reached 30 mg after approximately 110 hours. When the surface roughness is lowered to 0.4μ than that of the comparative example (surface roughness of 0.1μ), the leakage amount is 30mg after approximately 60 hours have passed after the start of continuous operation, as shown by line G in Figure 6. Record. As is clear from the above, the durability of mechanical seals can be determined based on the specific wear amount, but deterioration in seal performance such as oil leakage due to long-term operation is not necessarily proportional to the specific wear amount. It turns out that this cannot be said to be something that can be done. Furthermore, as is clear from the above examples, the mechanical seal of the present invention has a significantly small amount of specific wear even after long-term operation, and the deterioration of seal performance represented by the amount of oil leakage decreases over time. Since it only gradually increases with time and shows no tendency for rapid deterioration, it can be said that it has excellent durability and is stable.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams comparing the friction coefficient and wear amount of the mechanical seal of the present invention and a conventionally known mechanical seal or a mechanical seal previously proposed by the present inventor, and Figure 3 is a diagram comparing the friction coefficient and wear amount of the mechanical seal of the present invention. A cross-sectional view of a suitable swash plate type compressor for a car cooler, FIG. 4 is a detailed view of the mechanical seal shown in FIG. 3, FIG. 5 is a perspective view of the fixing piece in FIG. 4, and FIG. FIG. 3 is a diagram comparing the amount of oil leakage in a durability test of a mechanical seal previously proposed by the present inventors. In the figure, 1 is the cylinder bore, 2 is the cylinder block, 3 and 4 are the cylinder heads, 5 and 6 are the valve seats, 7 is the shaft hole, 8 is the oil reservoir chamber, 9 is the crank chamber, 20 is the rotating shaft, and 21 is the piston. , 22 is a swash plate, 30 is a mechanical seal, 31 is a fixed piece thereof, 38 is a rotating piece thereof, and 40 is a porous plating layer of chromium.

Claims (1)

[Scope of Claims] 1. A fixed piece attached to a fixed part, and a fixed piece attached to a rotating shaft that is rotatable with respect to the fixed part, rotated together with the rotating shaft, and slidably pressed against one surface of the fixed piece. It also has a rotating piece,
In a mechanical seal that maintains the airtightness of a sliding part through sliding rotation between the fixed piece and the rotating piece, one of the fixed piece and the rotating piece has a contact sliding surface with the surface of the surface. 1. A mechanical seal characterized in that a porous plating layer of porous chromium is applied, and the other of the fixed piece and the rotating piece is made of carbonaceous material. 2. The mechanical seal according to claim 1, wherein the chromium porous plating layer is provided on the surface of the fixed piece. 3. A patent claim characterized in that the pores appearing on the surface of the chromium porous plating layer have a diameter of 5 to 20 μm, and the number of pores appearing on the surface is 500 to 2000 per square mm. The mechanical seal according to item 1 or 2. 4 The porous plating layer has a hardness of
The mechanical seal according to claim 1 or 2, wherein the mechanical seal has an MHV of 800 to 1100. 5. Claim 1, characterized in that the porous plating layer of chromium is applied to the surface of the fixing piece whose main component is iron to a thickness of 5 to 200 μm.
The mechanical seal according to item 2 or item 2. 6. The mechanical seal according to claim 1, wherein the rotating piece is made of a kneaded mixture of carbon and/or graphite powder and synthetic resin. 7 The rotating piece is formed of a kneaded mixture of 30 to 80% of carbon and/or graphite powder, 2 to 15% of low friction additive powder, and the balance synthetic resin in weight percent. The mechanical seal according to claim 6, characterized in that: 8. The rotating piece is formed of a kneaded mixture of 40 to 70% carbon and/or graphite powder, 5 to 10% low friction additive powder, and the balance synthetic resin in weight percent. The mechanical seal according to claim 6, characterized in that: 9 The carbon and/or graphite powder has a particle size of 300 μm or less, preferably 100 μm.
Claim 6 is characterized in that:
Mechanical seals listed in section. 10. The mechanical seal according to claim 6, wherein the synthetic resin is any one of phenolic resin, epoxy resin, furan resin, and polyimide resin. 11. The mechanical device according to claim 7, wherein the additive powder is a powder of one or more of silicon dioxide, silicate, and boron nitride, the particles of which are 50 μm or less. sticker. 12 One side of the annular fixing piece fixed to the rotating shaft hole of the cylinder head fixed to the end face of the cylinder block on which the piston that is reciprocated by the swash plate of the swash plate type compressor is mounted, has a hole that appears on the plating surface with a diameter of 5 mm. ~20 μm, and the number of pores appearing on the surface is 500 to 2000 per square mm.
A porous plating layer of porous chromium is formed, and the rotating shaft to which the swash plate is attached is inserted through the center hole of the fixed piece, and the rotating shaft is
An annular carbonaceous rotating piece is attached to the rotating shaft by fitting its center hole, and the carbonaceous rotating piece is rotationally slid on the surface of the chromium porous plating layer of the fixed piece. Mechanical seal for swash plate type compressor. 13 The rotating piece, in weight percent,
Carbon and/or whose particle size is 300 μm or less
or 40-70% of graphite powder and the particle size is
5-10 of low friction additive powder that is 50μm or less
13. The mechanical seal according to claim 12, characterized in that the mechanical seal is formed of a kneaded molded product comprising: