JPH0151675B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a swash plate compressor, and more particularly to an improvement in a sliding mechanism interposed between a swash plate and a piston. Conventional technology A swash plate compressor consists of a swash plate fixed to a rotating shaft at a fixed angle, a piston installed parallel to the rotating shaft, and a sliding member interposed between the swash plate and the piston. The piston is reciprocated by the rotation of the swash plate, and gas is introduced into the cylinder and compressed. The sliding mechanism of this swash plate compressor has conventionally been composed of a combination of steel balls and shoes. One surface of the shoe is in sliding contact with the swash plate, and a concave spherical surface provided on the other surface supports a steel ball, and this steel ball engages with the concave spherical surface of the piston. As a result, there are problems such as an increase in the number of sliding parts, which increases manufacturing costs, an increase in the number of parts, which makes it difficult to reduce the size and weight, and also makes assembly workability and parts management complicated. In order to solve these problems, the present applicant has previously developed and filed an application for a swash plate compressor in which the shoe is omitted. Utility Application No. 121758 (1981)
-39329 Publication) and Japanese Patent Application No. 55-29667 (Japanese Patent Application Publication No.
56-126686), and the sliding mechanism of this swash plate compressor consists only of hemispherical sliders. This slider has a flat side surface in sliding contact with the swash plate and a spherical side surface in sliding contact with the concave spherical surface of the piston, making it possible to achieve reductions in size, weight, and cost. Problems to be Solved by the Invention However, the swash plate compressor equipped with this hemispherical slider is used as a refrigerant compressor for vehicle air conditioners, etc., which require a compact and lightweight design. When a lubrication method using mixed oil mist is adopted, if the engine is operated at low speeds such as when it is idling, the amount of lubricating oil supplied to the slider will decrease, creating harsh lubrication conditions. In some cases, there was a problem that the slider would seize. Further, there was a problem in that the frictional resistance between the spherical side surface and the concave spherical surface of the piston was high, and this combined with the difficulty in supplying lubricating oil to this portion resulted in a large power loss. The present invention has been made against the background of the above circumstances, and it takes advantage of the advantages of a swash plate compressor equipped with hemispherical sliders, such as fewer parts, lighter weight, and lower manufacturing costs. Furthermore, this was done with the aim of making it less likely to seize and to have less power loss. Means for Solving the Problems The gist of the present invention is to make the flat side surface of the slider a smooth convex curved surface with an extremely large radius of curvature and a height of 15 μm or less with the apex at the center, and A rounded portion smoothly connected to the convex curved surface is formed on the outer peripheral edge of the convex curved surface, and a lubricating film containing a solid lubricant is formed at least on the spherical side surface. In a particularly desirable embodiment of the present invention, the slider is made of steel, and a base treatment film consisting of a manganese phosphate conversion film or a soft nitrided film is formed on the spherical side surface of the slider, and the base treatment film is The lubricating film is formed thereon. The lubricating film is formed by bonding a solid lubricant containing a sulfide such as molybdenum disulfide or tungsten disulfide with a thermosetting resin binder such as a phenolic resin or an epoxy resin, and the lubricating film and The total thickness including the base treatment film is 10 μm or less. Further, the present invention is particularly effective when applied to the case where the slider is manufactured from a material formed into a substantially hemispherical shape by cold forging. Function In the swash plate compressor equipped with the slider described above, when the rotating shaft is rotated by a drive source such as an engine, the swash plate fixed to the rotating shaft is rotated,
The movement of the swash plate is converted by the slider into reciprocating movement of the piston. At this time, the slider oscillates and rotates on its own axis according to changes in the angle of the parts of the swash plate corresponding to the pistons, and high-speed friction occurs between the flat side of the slider and the swash plate. , considerable velocity friction also occurs on the spherical side. Moreover, this friction occurs under extremely high surface pressure. When a lubrication method using oil mist mixed in refrigerant gas is adopted and the amount of lubricating oil supplied is small, such as when the rotating shaft is driven at low speed, each sliding surface becomes extremely thin. Exposed to harsh sliding conditions. However, in the swash plate compressor according to the present invention, seizure does not occur between the slider and the swash plate or the piston, and power loss can be reduced. The reason is assumed to be as follows. There is an extremely small angle between the convex curved surface and the swash plate.
Moreover, since a wedge-shaped gap is formed in which the angle smoothly decreases, when sliding occurs at high speed, the lubricating oil attached to the swash plate is effectively drawn between the two due to the so-called wedge effect. , hydrodynamic lubrication is achieved. In addition, as the slider swings and rotates, the closest part or contact part between the convex curved surface and the swash plate changes from time to time, and the amount of lubricating oil contributing to fluid lubrication increases, making the lubrication conditions even more difficult. Improved. In addition, since the hemispherical slider is taller than the conventional shoe in relation to the size of its flat side, it is strongly affected by the rotational moment due to the frictional force between it and the swash plate. The leading edge of the flat side surface, that is, the edge on the side opposite to the direction of rotation of the swash plate, tends to be particularly strongly pressed against the swash plate, but since the flat side surface is a convex curved surface, the leading edge Reducing the pressure of the edges on the swash plate is also considered to be one of the reasons for the improvement in seizure resistance. When a rotational moment acts on the slider as described above, the presence of the convex curved surface allows the slider to swing at a minute angle. As the slider swings, the part of the convex curved surface closer to the leading edge approaches the swash plate, and the gap between them decreases, but this gap prevents lubricating oil from escaping. Because it is so small that it cannot be easily tolerated, a high oil film pressure is generated between the convex curved surface and the swash plate due to the slight rocking of the slider, preventing further rocking of the slider. play the role of deterrent. If the flat side of the slider is perfectly flat, even a slight swing of the slider will cause the leading edge to be pressed against the swash plate with high surface pressure, causing seizure. However, if a convex curved surface is formed on the flat side surface, such a situation can be avoided, the amount of heat generated is reduced, and seizing between the slider and the swash plate is prevented. However, when starting a compressor or at the top dead center or bottom dead center of a piston, when a load is applied to the slider on the previously unloaded side, the rotational moment that acts on the slider If it is difficult to generate an oil film pressure that can sufficiently counter the pressure, it is impossible to completely prevent the leading edge of the slider from being pressed against the swash plate. At this time, if sharp corners are formed on the outer periphery of the convex curved surface, the corners will feel like they are digging into the swash plate, making it difficult for the slider to slide, increasing power loss, and causing so-called Galling is more likely to occur. In contrast, in the present invention, a rounded part is formed on the outer peripheral edge of the convex curved surface to eliminate the above-mentioned corner part, and also to help form an oil film due to the wedge effect, thereby causing power loss and galling. can be effectively prevented.
In particular, when the compressor is started up, the slider slides on the swash plate with almost no lubrication, so the frictional force between the two is large, and the above-mentioned galling is likely to occur. Like the refrigerant compressor of
If starting and stopping are repeated fairly frequently, the operating conditions become extremely harsh. Therefore, the formation of the rounded portion has a particularly remarkable effect in a swash plate type refrigerant compressor for a vehicle air conditioner. In addition, in order to reduce the biting of the leading edge of the slider into the swash plate and to make it easier for the slider to rotate, it is necessary to reduce the frictional resistance between the hemispherical side surface of the slider and the concave spherical surface of the piston as much as possible. However, in the present invention, since a lubricating film containing a solid lubricant is formed on the spherical side of the slider, smooth rocking and rotation of the slider is guaranteed, and this point is improved. This also improves the seizure resistance of flat side surfaces. If a lubricating film is formed on the spherical side surface, not only will the small recesses on the spherical side surface itself be filled with the lubricating film, but also a portion of the lubricating film will also spread onto the concave spherical surface of the piston as the slider and piston slide. Because it adheres and fills even the smallest recesses, the substantial contact area between the slider and the piston increases, reducing local adhesion between the two and reducing frictional resistance. In this way, the lubricating film is expected to wear out with use, so if the lubricating film is too thick, the clearance between the swash plate, slider, and piston will increase after the lubricating film wears out. However, the operating noise becomes so loud that it becomes unsuitable for practical use. Therefore, it is desirable that the total thickness of the base treatment film and the lubricating film is 15 μm or less, and 10 μm or less.
The following is particularly desirable. As mentioned above, the frictional resistance between the spherical side of the slider and the concave spherical surface of the piston is reduced, allowing easy rocking of the slider, which also converts the movement of the swash plate into the movement of the piston. It is also effective in reducing the power loss when compressing and improving the operating efficiency of the entire swash plate compressor. The lubricating film on the spherical side works effectively in reducing power loss together with the rounded portion on the flat side. In a desirable state in which a base treatment film and a lubricating film are formed on the spherical side surface of the steel slider,
The surface treatment film has the effect of increasing the bonding strength between the lubricating film and the steel base material, but it is not only that.
After the lubricating film wears out, the base material of the slider and the piston will partially come into direct contact, so it also serves to prevent the two from seizing at this time. Additionally, if the slider is manufactured from a material that has been formed into an almost hemispherical shape by cold forging, the manufacturing cost can be reduced compared to when it is manufactured from a spherical material. Since the surface roughness of the spherical side surface tends to deteriorate, it is particularly effective to form a lubricating film. Effects of the Invention As described in detail above, according to the present invention, a swash plate compressor equipped with a hemispherical slider has the excellent advantages of having a small number of parts, being small and lightweight, and having a low manufacturing cost. Seizure resistance can be improved and power loss can be reduced. Embodiments Hereinafter, a case in which the present invention is applied to a swash plate compressor used in a cooling device for automobile air conditioning will be described in detail as an example. In FIG. 1, reference numerals 1 and 2 indicate cylinder blocks, and a compressor main body 3 is constructed by combining two cylinder blocks 1 and 2 of mutually symmetrical shapes. Each cylinder block 1, 2 has three (or five) cylinder bores 1a,
2a is formed parallel to the rotating shaft 5, and a double-ended Al-Si alloy (AC8A) is formed in these cylinder bores 1a, 2a.
A piston 4 made of aluminum is slidably fitted therein. A rotating shaft 5 is inserted through the center hole 3a of the compressor main body 3 and rotatably supported by bearings 6 and 7. A swash plate 8 made of Al--Si alloy (A390) manufactured by gravity casting is fixed to the center of the rotating shaft 5 by a spring pin 9. A steel slider 10 is disposed between the swash plate 8 and the piston 4, and when the swash plate 8 is rotated together with the rotating shaft 5, the driving force is transmitted to the piston 4 via the slider 10. The piston 4 is caused to reciprocate. 13 and 14 are thrust bearings. A front housing 20 is fixed to the end face of the cylinder block 2 with a suction valve seat 15, a valve plate 16, and a gasket 17 interposed therebetween. Three suction ports 16a and three discharge ports 16b are formed in the valve plate 16, and each of them cooperates with a suction valve seat 15 and a discharge valve reed (not shown) to form three suction valves 18 and a discharge valve. It consists of 19. Each suction valve 18 is provided at a position where it can suck refrigerant gas from a common suction chamber 21 formed in the front housing 20, and each discharge valve 19 is located at a position where it can discharge refrigerant gas into a common discharge chamber 22. It is provided. The rotary shaft 5 passes through the center of the front housing 20 and projects to the outside, and is connected to an engine as a driving source at the projecting end via an electromagnetic clutch. The rotating shaft 5 and the front housing 20 are kept airtight by a shaft sealing device 23. On the other hand, a rear housing 34 is fixed to the end face of the cylinder block 1 with a suction valve seat 31, a valve plate 32, and a gasket 33 in between, and each cylinder bore 1a is connected to a suction chamber 36 via a suction valve 35, and It is connected to a discharge chamber 38 via a discharge valve 37. The suction chambers 21 and 36 are communicated with each other by a suction passage (not shown) formed by passing through the compressor body 3 in the axial direction, and are connected to a suction pipe by a common suction flange (also not shown). has been done. Further, the discharge chambers 22 and 38 are holes 39 and 4 formed in the valve plates 16 and 32, respectively.
A common discharge flange 43 is formed by the discharge passages 41 and 42 formed in the cylinder blocks 2 and 1.
It is connected to the. The slider 10 has a hardness adjusted to approximately 60H _R C (Rockwell C scale hardness), and, as shown in FIG. 2, has a spherical side surface 10a and a flat side surface 10b. The flat side surface 10b is formed into a smooth convex curved surface 10c with an extremely large radius of curvature, with the height being the most desirable value of 2 to 5 μm, and the outer periphery of the flat side surface 10b has a convex curved surface 10c. A chamfered surface 10d having a smaller inclination angle θ is formed. Since the convex curved surface 10c is visible to the naked eye as a flat surface, its existence cannot be confirmed, but according to the measuring machine, the convex curved surface 1 shown in FIG.
The height H1 of the convex curved surface 10c is the contact point 12a of the convex curved surface 10c with the circle of the rounded part 10e formed at the boundary with the adjacent chamfered surface 10d. It is measured as the height from to its apex. Note that such a slider may be manufactured by cutting a steel ball and finishing it so that the convex curved surface 10c and the chamfered surface 10d are formed on the cut surface, but in this example, cold forging is used. A molded product is used. Further, the slider 10 of this embodiment has a film containing a solid lubricant (hereinafter simply referred to as a lubricant film) formed on the entire surface. Molybdenum disulfide (MoS ₂ ) and tungsten disulfide (WS ₂ ) are solid lubricants.
Sulfides such as sulfides are suitable, but various solid lubricants such as graphite (C), boron nitride (BN), and polytetrafluoroethylene resin ((CF ₂ - CF ₂ ) n) may also be used in conjunction with these sulfides. is possible. In this example, a mixture of four types of powders, molybdenum disulfide, boron nitride, graphite, and polytetrafluoroethylene resin, is used. The entire surface of the material is coated to form a lubricating film. The method for forming this lubricating film will be briefly described below. First, the slider as the object to be treated is degreased in an alkaline solution such as caustic soda at 60 to 70°C, and then washed with water and then hot water to remove alkali adhering to the surface. The degreased workpiece is then heated to 85~95
By immersing it in an aqueous manganese phosphate solution at 0.degree. C., a manganese phosphate chemical conversion film is formed on the surface as a base treatment film. If necessary, an accelerator may be added to the manganese phosphate treatment solution to shorten the treatment time. Once the manganese phosphate conversion film has been formed, it is washed with hot water and dried with hot air, and then the coating material diluted with a suitable diluent is applied to the entire surface by spraying. Then, heat this at 180℃ for 30 minutes.
Alternatively, the desired lubricating film can be formed by baking at 150°C for 1 hour. Note that this lubricating film inevitably undergoes plastic flow and abrasion during use of the compressor, resulting in a decrease in its thickness. If the film thickness decreases, a gap will be created between the slider 10 and the piston 4 or the swash plate 8, which will cause an increase in operating noise. It is necessary to adjust the spray conditions so that the amount is below a predetermined value. This value is generally
It is desirable that the thickness be 10 μm or less, more preferably 7 μm or less, and even better if it is 5 μm or less. By the way, hydrogen is generated during the above-mentioned phosphate treatment, and there is a risk that the object to be treated may absorb this hydrogen and become brittle. Perform brittleness removal treatment. The base treatment film may be not only the manganese phosphate chemical conversion film described above, but also a nitrided film formed by soft nitriding using the tuftride method or the like. The coating material can be applied by spraying, tumbling, dipping, brushing, etc. The slider 10 manufactured in this manner has a spherical side surface 10a in contact with a concave spherical surface 11 provided on the piston 4, and a flat side surface 10b in sliding contact with the swash plate 8 on both sides of the swash plate 8. It is arranged. In the swash plate compressor configured as described above, when the rotating shaft 5 is rotated by a drive shaft such as an engine (not shown), the swash plate 8 fixed to the rotating shaft 5 is rotated and simultaneously slides. The piston 4 is caused to reciprocate via the child 10. Therefore, the slider 10 is caused to swing and rotate while sliding on the concave spherical surface 11 of the piston in response to changes in the contact angle of the surface of the swash plate 8 with respect to the piston 4. At this time, a frictional force is generated between the spherical side surface 10a of the slider 10 and the concave spherical surface 11 of the piston 4, and this frictional force is caused by the fact that it is relatively difficult to supply lubricating oil to these sliding surfaces. This becomes larger and causes power loss in the compressor. Moreover, a hemispherical slider formed by forging and without a lubricating film has a higher surface roughness than one made by cutting a steel ball, and the concave spherical surface 11 is formed by cutting. The power loss is further exacerbated by the large roughness. On the other hand, in the above-mentioned compressor equipped with the slider 10 having a lubricating film formed on its surface, the slider 10 slides smoothly without such problems, and the frictional force and power loss are effectively reduced. It is reduced to . The lubricating film formed on the surface of the slider 10 has the following effect on reducing frictional force and power loss. Microscopically, the spherical side surface 10a of the slider 10 and the concave spherical surface 11 of the piston 4 have many irregularities, and when the slider 10 is pressed against the piston 4 with a high load, these irregularities occur. Metallic contact occurs locally between the two, causing local adhesion and an increase in frictional force. However, the lubricating film coated on the surface of the slider fills the recesses and smooths the protrusions on the surface when plastically flowing.
The real contact area of the piston 4 and the piston 4 are increased to improve compatibility between the two. That is, due to the action of the solid lubricant, the slider 10 and the piston 4 are brought into even contact over a wide surface, thereby reducing the surface pressure between them. Combined with the lubricating action inherent to the solid lubricant, a reduction in frictional force and power loss is achieved.
In other words, the lubricating film coated on the surface of the slider 10 acts to cover irregularities in the sliding surface in addition to its original lubricating effect, and therefore causes waviness and a large number of scratches on the surface. Even in a slider formed by forging, which tends to have irregularities, no problems arise. In other words, this lubricating film is particularly effective when coated on a slider formed by forging, which allows the slider 10 to be manufactured at a low cost. . By the way, the cost of manufacturing by forging is about half that of cutting steel balls. It has been confirmed through the following experiments that the lubricating film of the above embodiment formed on the slider 10 has an excellent effect on reducing power loss. In addition to power loss measurements, the experiments also included measurements of the friction coefficient and seizure properties of the lubricating film. Experimental Example Experiment Preparation of Samples Four types of samples were prepared using hemispherical sliders formed by forging with various conditions such as surface treatment, type of coating material, coating method, etc. as shown in Table 1.

[Table] Created. Note that other treatment conditions such as degreasing treatment and firing treatment were carried out in accordance with the above-mentioned method. The obtained samples A to D were subjected to the following experiment together with a forged slider E without a lubricating film and a slider F without a lubricating film produced by cutting a steel ball. Experiment As shown in FIG. 4, the spherical side of the slider 102 was brought into contact with the concave spherical surface of the block 100 made of the same material as the piston, and the flat side was brought into contact with the rotating body 104 made of the same material as the swash plate. Pressure load P of 100Kg
is applied to bring them into contact, and in this state, the rotating body 104 is
The friction coefficient of the spherical side surface was measured 10 minutes and 60 minutes after rotating at 500 rpm. The results are shown in Table 2. The experiment was conducted in lubricating oil.

[Table] As is clear from Table 2, the friction coefficients of the samples A to D having a lubricating film are considerably smaller than those of the samples without a lubricating film, which shows how effective the lubricating film is. Experiment Using the same equipment as in the experiment, the pressing load P was 20
Kg, and the rotational speed of the rotating body 104 was set to 300 rpm, and the time until seizure occurred was measured. The experiment was conducted in air without lubrication. The results are shown in Table 3. This result shows that the formation of a lubricating film is also effective in preventing seizure.

[Table] Experiment Samples A to F were actually installed in a swash plate compressor with a total displacement of 150 c.c./rev., and the degree of power loss was investigated by operating with the regular refrigerant gas and lubricating oil filling amounts. The results are shown graphically in FIG. As is clear from Fig. 5, sample E is a slider formed by forging.
has a larger power loss than sample F, which is a slider made by cutting steel balls, but samples A to D, which have a lubricating film formed on the slider formed by forging, have a higher power loss than samples E and F. Power loss is small, and samples A~
Among D, solid lubricants include molybdenum disulfide (MoS ₂ ), boron nitride (BN), graphite (C), and polytetrafluoroethylene resin (CF ₂ -
It is understood that sample C using CF ₂ )n is the best. Note that lubricating oil is relatively easily supplied to the flat side surface 10b of the slider 10, and the formation of a lubricating oil film can be promoted by forming the convex curved surface 10c and the chamfered surface 10d. This formation is particularly effective on the spherical side surface 10a, where it is difficult to improve the surface roughness and form a lubricating oil film compared to the flat side surface 10b, and therefore the lubricating film may be formed only on the spherical side surface 10a. Incidentally, frictional force is also generated on the flat side surface 10b of the slider 10, that is, the surface that contacts the swash plate 8.
The solid lubricating film has the same effect as on the spherical side surface 10a to reduce the frictional force, but the shape of the flat side surface 10b is convexly curved so that it bulges out slightly, so the lubricating film is Even if it wears out, seizure between the slider 10 and the swash plate 8 can be effectively prevented due to the effect of this convex curved shape and because the hardness is adjusted to be high. . This effect has been confirmed by the following experiment. Experiment Using slider samples with convex curved surfaces 10c of different heights H1 and samples without convex curved surfaces, the swash plate 8
FIG. 6 shows the results of measuring the pressing load (seizing load) when seizure occurs by pressing the sample against a rotating plate made of the same material as the sample and gradually increasing the pressing force.
Note that this experiment was conducted under the following conditions. Friction speed V between rotating plate and slider: 15m/sec Pressing load: 20Kg/20 minutes gradual increase method Lubrication conditions: Part lubrication method (0.4cc/min) Oil type: Refrigerating machine oil 1/light oil 9 Slider: Material Steel (SUJ-2) Diameter of spherical side surface 13.5mm Surface roughness 0.3μm or less Rotating plate: Straightness 1μm to 1.5μm Material Al-Si alloy (A390) Surface roughness 0.7μm or less Sample with convex curved surface 10c formed According to the solid line in FIG. 6 showing the experimental results, if the height H1 of the convex curved surface 10c is even slight, the seizure load will exceed 250 kg,
The seizure load reaches its maximum (more than 500 kg) when the height H1 is about 5 μm, and then gradually decreases until the height H1 increases.
If it exceeds 15μm, the seizure load will be less than 250Kg. On the other hand, according to the dotted line in the same figure showing the results of the sample in which no convex curved surface is formed, the seizure load of the slider, which is literally a flat surface with no convex curved surface 10c formed on the flat side surface 10b as shown in FIG. is 160Kg, and when a rounded portion 10e is provided at the boundary between the chamfered surface 10d and the flat side surface 10b, the rounded portion 1
It reaches a maximum (300 kg) when the height H2 of the flat side surface 10b including 0e is 3 μm, and then gradually decreases.
Note that the height H2 is measured as the height from the point of contact 12b between the circle having the radius of curvature of the rounded portion 10e and the chamfered surface 10d to the flat surface. In this way, compared to the slider having the flat side surface 10b, which is literally a flat surface, the seizure load of the slider 10 having the convex curved surface 10c is always superior, especially when the height H1 of the convex curved surface 10c is In the range of 15μm or less, a higher level of seizure load than conventional products of 250Kg or more is secured. Experiment On the other hand, according to an experiment conducted to investigate the relationship between the height H1 of the convex curved surface 10c and the amount of wear, slider samples with different heights H1 of the convex curved surface 10c were made of the same material as the swash plate 8 (Al- When pressed against a rotary plate made of Si-based alloy A390) with a constant load, the amount of decrease in height after a predetermined period of time is as shown in the graph of FIG. Note that this experiment was conducted under the following conditions. Friction speed V between rotating plate and slider: 15m/sec Pressing load per unit area ^cm2 : 100Kg (25Kg during break-in) Test time: 100 hours (after 30 minutes break-in time) Lubrication conditions and oil type : Same as experiment Slider : Material Steel (SUJ-2) Surface roughness 0.3 μm or less Diameter of spherical side surface 13.5 mm Rotating plate : Same as experiment According to the graph in Figure 8, height H of convex curved surface 10c
1 exceeds 7 μm, the amount of decrease in height H1 (amount of wear) increases rapidly. This increase in the amount of wear causes play between the swash plate 8, the piston, and the slider 10, causing vibration and noise, or shortening the life of the compressor. Therefore, according to the results of both of the above experiments, the height of the convex curved surface is preferably 7 μm or less in order to improve the seizure load without increasing the amount of wear on the slider 10, and more preferably 2 μm or less. ~
The height is 5μm. Experiment The slider was pressed against the surface of the rotary plate with a constant load under each sample condition shown in Table 4, and the time until the slider reached seizure was measured. The results are shown in Figures 9 and 10. Shown below. Note that this experiment was conducted under the following conditions. Friction speed V between rotating plate and slider: 15 m/sec Pressing load per unit area ^cm2 : 120 kg (25 kg during break-in) Test time: 50 hours (maximum) Lubrication conditions: Part lubrication method Oil type: Frozen Oil mixture of 1 part machine oil and 9 parts diesel oil Slider: Diameter of spherical side surface 13.5 mm Height of convex curved surface 3 μm Surface roughness of convex curved surface 0.3 μm or less Rotating plate: Straightness 1.0 μm to 1.5 μm Al-Si alloy (10 ~25%Si) Surface roughness 0.7μm or less

【table】

[Table] According to Figures 9 and 10, the time until seizure depends on the type of chromium-containing steel of the slider and the type of rotating plate.
It is not so much affected by the silicon (Si) content of the Al-Si alloy, but is most affected by the hardness of the material of the slider. It becomes less likely to occur. That is, if the hardness is 50 H _R C (Rockwell hardness) or more, a practically satisfactory anti-seizure effect can be obtained, and it is more desirable if the hardness is 60 H _R C or more.
Note that the x mark in FIG. 9 indicates the occurrence of seizure, and the solid line, broken line, and one-dot chain line in FIG. 10 indicate that the silicon content of the aluminum alloy is 18%, 10%, and 25%. Further, the hardness of the Al-Si alloy is 17 to 42 H _R C (Rockwell hardness) at a silicon content of 10% to 25%. Experiment Using a swash plate compressor with a total displacement of 150 c.c./rev, the amount of lubricating oil in the compressor was set at various levels (10 levels), and the amount of lubricating oil in the compressor was set at various levels (10 levels). Table 5 and FIG. 11 show the results of an experiment to determine the presence or absence of seizure, which was repeated for each sample condition of the slider and swash plate shown in Table 4. Note that this experiment was conducted under the following conditions. Rotation speed: 4000 rpm Refrigerant discharge pressure: 4 to 6 Kg/cm ² Refrigerant suction pressure: Approximately -50 mmHg Operating time: 20 hours Refrigerant gas: 100 g (10% of normal amount) Slider and swash plate: Experimental slider and the same conditions as the rotary plate Lubricating oil: Refrigeration oil Amount of oil filled: 100 to 270 c.c. Swash plate: Al-Si alloy (10 to 25% Si) Piston: Al-Si alloy (AC8A)

【table】

[Table] According to Table 5 and Figure 11, the amount of lubricating oil that causes seizure is determined by the type of slider material and the swash plate.
It is not so much affected by the silicon (Si) content of the Al--Si alloy, but is most affected by the hardness of the material of the slider, and the higher the hardness, the smaller the amount of lubricant oil required to cause seizure. This means that seizure will not occur even under severe lubrication conditions such as when operating at low speeds. In other _words , the results of this experiment, similar to the above-mentioned experimental results, indicate that in practice, if the hardness of the slider is 50 (H _R C) or higher, a desired anti-seizure effect can be obtained;
This indicates that it is more desirable if it is above. Note that in Table 5, the ◯, △, and × marks indicate a state in which there is no burn-in on all the pieces, a state where there is some burn-in in a plurality of pieces, and a state where there is burn-in on all of the pieces. In addition, the solid line, broken line, and dashed-dotted line in Fig. 11 are Al-
Silicon content of Si-based alloy is 18%, 10% and 25%
. According to the above experimental results, the swash plate 8 is made of Al
- Made of Si-based alloy, convex curved surface 1 on flat side surface 10b
When a slider 10 made of chromium-containing steel with 0c formed thereon is used, in order to prevent seizure of the slider, the hardness of the slider 10 must be 50 (H _R C) or more. In order to obtain a certain effect and a more reliable effect, it is desirable that the hardness is 60 (H _R C) or higher. Note that the swash plate 8 and the convex curved surface 10 are in sliding contact with each other.
Of course, it is better for the surface of c to be smoother in order to prevent seizure. That is, the swash plate 8
The surface roughness of the slider 10 is preferably 1 μm or less, especially 0.7 μm or less, and the surface roughness of the slider 10 is 1 μm or less, especially
Desirably 0.3μm or less. Further, the angle of the chamfered surface 10d, which is formed to actively draw lubricating oil between the sliding surfaces and promote the formation of an oil film, with respect to the flat side surface 10b is preferably 1 to 45 degrees, particularly 5 to 15 degrees. Experiment Performance experiments were conducted by actually incorporating two types of sliders according to the present invention and two types of sliders as comparative samples into a swash plate compressor. The required horsepower per ton of refrigeration was measured by changing the rotation speed of the compressor into multiple types. The horsepower required per 1 ton of refrigeration depends on the sliding resistance between the slider 10 and the swash plate 8, so by measuring this it is possible to check the quality of the sliding. be. The experimental conditions are as follows. Discharge side gas pressure: 15Kg/cm ^2Suction side gas pressure: 2Kg/cm ^2Lubricating oil: Refrigerating machine oil 80c.c. Swash plate: Made of A390 Gas amount: 800g Each curve A, B, C, D in Figure 12 is The results are shown for the following samples. Convex curved surface Rounded part Chamfered surface A Yes (H1 = 3μm) Yes Yes B Yes (H1 = 3μm) Yes No C Yes (H1 = 3μm) None Yes D None Yes Yes (H2 = 3μm) As is clear from Fig. 12 , a convex curved surface 10c,
The slider A according to the present invention, which has both the chamfered surface 10d and the rounded portion 10e, is the best, and has the convex curved surface 1.
The slider B according to the present invention, which includes the slider 0c and the rounded portion 10e but does not include the chamfered surface 10d, is the next best. From this result, the convex curved surface 10c and the rounded part 10e
It can be seen that the sliding resistance can be further reduced by providing a chamfered surface 10d on the slider equipped with the above.
On the other hand, all of the sliders of the comparative samples are inferior to the slider according to the present invention, especially when the convex curved surface 10
c and a chamfered surface 10d, but a rounded portion 10e.
The required horsepower is particularly high in the case of the slider C which is not equipped with. From this, it can be seen that the rounded portion 10e greatly contributes to reducing the sliding resistance. It should be noted that the lubricating film has a similar effect not only on sliders made by forging but also on sliders made by cutting steel balls, and this reduces power loss. Of course. Further, the surface of the slider that contacts the swash plate, that is, the flat side surface, may be formed in various shapes other than the shapes described in the above embodiments. For example, a flat side surface is made into a smooth convex curved surface with a large radius of curvature with a height of 15 μm or less with the apex at the center and looks like a flat surface to the naked eye, and one or two steps are added to the outer periphery of this convex curved surface. The one with a chamfered surface was patented in 1984.
As disclosed in Japanese Patent Application No. 125032 and Japanese Patent Application No. 126432/1983, reduction of frictional force and power loss can also be achieved when this slider is coated with a solid lubricant.

[Brief explanation of drawings]

FIG. 1 is a sectional view taken along the axis of a swash plate compressor showing an embodiment of the present invention. Fig. 2 is a front view showing the slider of the embodiment shown in Fig. 1, and Fig. 3 is a diagram showing the profile when the shape of the flat side surface of the slider shown in Fig. 2 is measured with a measuring machine. It is. FIG. 4 is a sectional view showing the test apparatus. FIG. 5 is a graph showing the measurement results of power loss. FIG. 6 is a graph showing the results of the experiment. FIG. 7 is a graph showing an enlarged profile of the flat part of the slider without a convex curved surface used in the experiment. FIG. 8 is a graph showing the results of the experiment. 9 and 10 are graphs showing the results of the experiment, FIG. 11 is a graph showing the results of the experiment, and FIG. 12 is a graph showing the results of the experiment. 1a, 2a: cylinder (cylinder bore), 4:
Piston, 5: Rotating shaft, 8: Swash plate, 10: Slider, 10a: Spherical side, 10b: Flat side, 10
c: convex curved surface, 11: concave curved surface, 10e: rounded part, 1
1: Concave spherical surface.

Claims (1)

[Scope of Claims] 1. A swash plate fixed at a fixed angle to a rotating shaft, a piston provided parallel to the rotating shaft, and a spherical side surface and a flat side surface, forming a substantially hemispherical shape. a slider that contacts a concave spherical surface formed on the piston on a spherical side surface and slides on the swash plate on a flat side surface to transmit the driving force of the swash plate to the piston; In a swash plate type compressor in which a piston is reciprocated as a result of A beveled surface having a convex curved surface, a rounded portion smoothly continuous to the convex curved surface formed on the outer peripheral edge of the convex curved surface, and a lubricating film containing a solid lubricant formed on at least the spherical side surface. Plate compressor. 2. The slider is made of steel, a base treatment film consisting of a manganese phosphate chemical conversion film or a soft nitrided film is formed on the spherical side surface, the lubricant film is formed on the base treatment film, and the lubricant film is formed on the base treatment film. The lubricating film is formed by bonding a solid lubricant containing a sulfide such as molybdenum disulfide or tungsten disulfide with a thermosetting resin binder such as a phenolic resin or an epoxy resin, and the lubricating film and the base treatment film are 2. The swash plate compressor according to claim 1, wherein the total thickness of the swash plate compressor is 10 μm or less. 3. The swash plate compressor according to claim 1 or 2, wherein the slider is manufactured from a material formed into a substantially hemispherical shape by cold forging.