JPS6118024B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a compressor, and in particular to a swash plate type compressor that has recently become widely used for car coolers.The main purpose of the present invention is to provide a compressor with higher performance and a longer lifespan than conventional compressors of this type. It's about doing. As shown in FIG. 1, the swash plate type compressor generally includes a piston 3 moored to a swash plate 5 in a state spanning the swash plate 5, and the piston 3 moves as the swash plate 5 rotates.
The reciprocating motion of the compressor draws in and compresses a medium to be compressed, such as refrigerant gas. The swash plate 5 is rotatably supported by a shaft 4 by a cylinder block 1.
The piston 3 is moored to the swash plate 5 via a shoe 6 and a ball 7. When the shaft 4 and the swash plate 5 are rotated together, the swash plate 5
While sliding on the sliding surface of the swash plate 5, the movement of the outer peripheral portion of the swash plate 5 in the axial direction is transmitted to the piston 3 via the balls 7. In this basic structure, the medium to be compressed, such as refrigerant gas, which has circulated within the refrigeration circuit and returned to the compressor, is compressed to high pressure within the cylinder bore 2 by the piston 3 and then transferred to the condenser (not shown). A cycle in which the air is sent out, cooled and liquefied there, and then sent to an evaporator where it evaporates and removes the latent heat of vaporization from the surroundings to cool the indoor air, while the removed heat is released into the air (atmosphere) while passing through the condenser. It is made to repeat. However, when such a swash plate type compressor is used for a car cooler, the operating conditions are extremely severe. That is, the driving source is an internal combustion engine such as gasoline or diesel, and the compressor is designed to have a rotational speed almost the same as that of the internal combustion engine for the purpose of reducing the size and weight of the compressor and the compressor capacity. Therefore, the rotation speed of the swash plate compressor is subject to conditions ranging from approximately 500 rpm, which is the rotational speed of the internal combustion engine when it is idling, to approximately 6000 rpm, such as when driving at high speeds or accelerating suddenly. Additionally, although this problem is not limited to swash plate type compressors, as vehicles have become lighter in recent years, compressors themselves have been required to be smaller and lighter. As the amount of lubricating oil is reduced in order to improve the performance of the compressor, friction and wear are becoming more likely to occur in the sliding parts within the compressor. Furthermore, the increase in temperature in the engine room due to the installation of various devices in the engine room in recent years, such as exhaust gas control devices and devices to reduce fuel consumption, has an adverse effect on the lubricating oil in the compressor. It's disappearing. In a swash plate type compressor used under these conditions, the part most adversely affected by the above conditions is the sliding portion between the swash plate 5 and the shoe 6 shown in FIG.
The sliding speed is approximately 2 to 3 m/sec when the engine is idling, and approximately at maximum rotation.
This is because at 6000 rpm, it is 20 to 25 m/sec, and even during normal running, they slide at extremely high speeds of about 7 to 15 m/sec. In addition to such high-speed sliding motion, a load acts on the shoe to compress the medium to be compressed, such as refrigerant, and the magnitude of the load is 60 to 130 kg/ ^cm2 , and the sliding speed and Although it is rare for pressures to have the maximum combination, the PV value (pressure in PKg/cm ² and velocity in V
m/sec) can often exceed 2000. Moreover, this is repeated in relation to the rotational speed. The load that the shoe receives from this repetition becomes an impact load, especially at high speeds, and the extremely harsh conditions of sliding at high speed while receiving such impact load are necessary for the sliding part between the swash plate and the shoe. It happens. Furthermore, when looking at the sliding condition between the swash plate and shoe from the lubrication perspective, with the removal of the oil pump as mentioned above, the lubricating oil supplied to the sliding parts is only supplied in the form of a mist by mixing with the refrigerant gas. becomes.
This is because a swash plate compressor without an oil pump is generally lubricated by circulating refrigerant gas containing oil around each sliding part within the compressor, but in this case, oil This is because the amount of oil is inversely proportional to the cooling capacity, so reducing the amount of oil is an effective means of increasing the cooling capacity of the swash plate compressor. From another perspective, it is the lubrication conditions that have the most influence on the life of the sliding parts of the swash plate and the shoe, and in particular, the amount of lubricating oil has the most influence. Therefore, in the midst of these conflicting relationships, what is particularly considered when designing a swash plate type compressor is the material of the swash plate and shoe that can meet the harshest sliding conditions. Furthermore, the sliding motion between the swash plate and shoe is a thrust sliding motion in which it is difficult to obtain a sufficient lubrication effect even if a sufficient amount of oil is supplied, so the sliding surfaces must always be under boundary lubrication. , or there is solid contact there, and this is a phenomenon that occurs because the swash plate compressor for a car cooler performs unsteady rotational movement that is inevitable in its use.
Lubricating oil is not supplied to the sliding surfaces between the swash plate and the shoe for several tens of seconds or even several minutes after startup, so during this period, the swash plate and shoe are completely unlubricated. It will be operated under conditions of solid contact. This situation can occur when refrigerant leaks from the pipes and the amount of refrigerant confined in the refrigeration cycle decreases, or when the amount of refrigerant returned to the compressor is caused by the operation of the evaporation pressure regulating device attached to the evaporator. It is also caused when the Therefore, among the various troubles that have arisen in conventional swash plate compressors, the most common problem is the seizure that occurs without lubrication from the time of startup, and the wear that occurs without lubrication can become a fatal defect. This caused burn-in to occur over time. Traditionally, swash plates have been made of structural materials with mechanical rigidity, fatigue strength, and wear resistance, as materials that can withstand the above-mentioned lubrication conditions, as well as materials that can withstand the high surface pressure and impact loads mentioned above. Alloy steels such as nickel chrome steel, nickel molybdenum steel, chrome molybdenum steel, and spheroidal graphite cast iron were used, and the surface layer was hardened. In addition, the ball was mainly made of high carbon chromium steel in order to withstand high loads. The shoe materials include Algyl alloy, phosphor bronze, copper-lead-tin alloy, brass, high-strength brass alloy, bronze alloy, aluminum bronze alloy, Babitt metal,
Oil-impregnated bearing alloys were considered. However, none of the materials known to date have been able to fully satisfy the aforementioned extremely harsh operating conditions unique to swash plate compressors for car coolers. The applicants previously discovered that a bimetallic material made by sintering copper-lead-tin alloy powder on a steel plate is the only material that can extend the lifespan, and filed a patent application.
No. 49-109856, but even the material related to this application is not necessarily sufficient for swash plate type compressors, which require smaller size and higher performance, and cannot be said to be sufficient for swash plate compressors that require smaller size and higher performance. Therefore, it is desired to develop a material with a long life that has properties that are even more improved than conventional ones, such as excellent wear resistance that prevents seizure from occurring. -ing In view of the above circumstances, the inventors of the present invention have conducted various research and development and have found that the sliding speed is 2 to 2.
25m/sec repeated operation and surface pressure 130~140
It can withstand repeated shock loads of Kg/cm ² , and the supply of lubricating oil is extremely small, it is supplied in the form of a mist along with refrigerant gas, and it can withstand sliding without lubrication for several seconds to several minutes after startup. The present invention was completed by discovering an excellent alloy material and applying it to a sew material for swash plate type compressors, particularly car coolers. In other words, the present invention solves all of the problems of the conventional methods described above, by using a copper alloy that is strengthened to the extent that the thermal conductivity is not significantly reduced, has little reduction in hardness especially at high temperatures, and has good sliding properties. The purpose of the present invention is to provide a swash plate compressor as described above, in which copper (Cu) is used as the main sew material, and elements from Group A of the periodic table and elements from Group A of the periodic table are used. Contains one or more elements selected from the group consisting of Group A elements in a total amount not exceeding 3% (based on weight, the same applies hereinafter), and further contains 0.5 to
The purpose is to use a Cu alloy containing 15% lead (Pb) or 0.5 to 15% Pb and less than 5% (not including zero) tin (Sn). The Group A and Group A elements used in the present invention are mainly used to disperse precipitates caused by crystallization and precipitation phenomena in the Cu base material (matrix) to strengthen the matrix. By containing at least one kind of element, Cu is effectively strengthened, and moreover, 200
It not only provides heat resistance that does not reduce hardness even at high temperatures of 0.degree. C. or higher, but also improves its wear resistance. In particular, among the Group A and Group A elements, chromium (Cr),
It is one or a combination of two or more of titanium (Ti) and zirconium (Zr), and the addition of Cr can increase the strength of the alloy by causing precipitation hardening. However, since excessive addition of Cr makes the entire alloy brittle, the appropriate blending ratio of Cr required to improve the strength during precipitation hardening is 3% or less. Furthermore, Ti has the effect of strengthening the alloy through heat treatment, and its precipitation can increase the hardness of the alloy. The appropriate proportion of Ti required to improve the strength during precipitation hardening is 3% or less. Furthermore, Zr can form intermetallic compounds with other alloying elements to strengthen the alloy, and such strengthening by intermetallic compounds can be achieved by introducing the elements separately in equal amounts into the composition of the intermetallic compound. It is even more effective than However, the amount of Zr added is 3%
If the amount exceeds 3%, the thermal conductivity will drop sharply, so in the present invention, the amount of Zr added is appropriately determined within a range not exceeding 3%. Note that these examples do not mean that the group a and group a elements according to the present invention are limited to the above three types, and other elements such as molybdenum and tungsten can be used as well, and such group a elements can also be used. , part a
When two or more elements of the same group are used, the total amount should be within 3%. This is because addition of more than 3% in total may cause problems such as embrittlement of the entire alloy. Also,
Although it is difficult to unambiguously determine the lower limit of the amount of these Group A and Group A elements, since even a small amount of these elements can have some effect, it is generally Approximately 0.1 even if two or more elements are added
% (total amount), thereby achieving a sufficient improvement in mechanical strength. In addition, along with the elements of group a and group a,
Lead (Pb) added to Cu is a low melting point material (melting point below 400℃) that does not solidify into the Cu base material, and by adding such Pb or a Pb alloy mainly composed of Pb, which is a low melting point material. , Furthermore, the sliding characteristics of the shoe,
In particular, conformability and slipperiness can be significantly improved. With this effect, various troubles caused by sliding of the shoe under no lubrication during start-up and under boundary lubrication during operation, which are particular to high-performance swash plate type compressors, can be more effectively resolved. It happens. In addition, in order to fully exhibit the effect of adding Pb, it is necessary to add an amount of 0.5 to 15%, and if the amount added is less than 0.5%, the desired compatibility cannot be obtained, and 15 %, it is difficult to uniformly disperse it in the alloy, and special manufacturing methods are required.
Furthermore, this is undesirable because it reduces the strength of the matrix. Furthermore, in addition to these additive elements, Sn, which is added to Cu, has a different effect from that of Pb, and Cu
Not only does it strengthen the matrix by solid solutioning it, but it also lowers the friction coefficient in terms of sliding properties, and this friction coefficient remains stable even at high temperatures. It exhibits excellent seizure resistance under various conditions.
However, since such added Sn dissolves in Cu as a solid solution as described above, it tends to reduce the thermal conductivity of the alloy, and therefore the range of its addition is limited. In this sense, 5% is adopted as the upper limit of Sn addition, and therefore the amount of Sn to be added is determined as appropriate within the range of less than 5% (of course, zero is not included), and the appropriate amount of Sn to be added is The most desirable content is about 1 to 3%. Therefore, the alloy according to the present invention, in which Cu is used as the base material and to which the above-mentioned Group A and Group A elements and Pb are respectively added, has an alloy composition that has excellent characteristics as a shoe material. . However, when using a swash plate compressor sash for a car cooler when the amount of lubricating oil is small, the most important issue is the thermal conductivity of the sew, and the elements that have the greatest effect on that thermal conductivity are the added elements. Furthermore, a large increase in the coefficient of friction is a direct cause of heat generation, so it is important to strengthen the matrix and improve conformability with as few additive elements as possible for a swash plate type compressor sash for high-performance car coolers. This is because it is a key point in determining whether or not it can be adapted to the current situation. During normal operation, a certain amount of lubricating oil is supplied, although it is relatively small.In particular, as a shoe material, rather than emphasizing compatibility, it is important to have good thermal conductivity, effectively dissipate heat, and high temperature. The sliding performance of the shoe is influenced by minimizing the decrease in hardness and structural changes at the bottom. In this sense, Group A and Group A elements have important effects, but on the other hand, Pb, which is a low melting point material added mainly for the purpose of improving compatibility, is not very noticeable during normal operation. It does not have any effect. However, on the other hand, when the engine is operated under conditions that are closer to no lubrication than at the time of startup, the conformability effect of the low melting point material Pb is greatly exhibited. Furthermore, even if the swash plate type compressor for high-performance car coolers is designed to eliminate the problem in a short time by improving the no-lubrication situation at startup, it will not be possible to eliminate it completely. Moreover, reductions in the amount of oil and refrigerant gas occur occasionally even during normal operation, and the material of the shoe is required to have various performances to be able to cope with these various conditions. Therefore, the selection and amount of additive elements according to the invention,
The degree of reinforcement and thermal conductivity resulting from this must be fully considered, and the most appropriate combination is Cu.
It is desirable to add at least one element selected from Group A and Group A, as well as Pb and Sn. In particular, in order to eliminate the harmful effects of having too many solid-solution elements, such as structural heterogeneity and decreased thermal conductivity due to intermetallic compounds, and brittleness caused by over-hardening of the matrix, we have developed a method that does not cause the above-mentioned harmful effects. By using the additive element by precipitation according to the present invention, which can be strengthened by precipitation, it is possible to expect resistance to seizure and wear resistance due to the precipitates, and it is possible to achieve this without significantly lowering the thermal conductivity. In addition,
Normally, when selecting a sliding material, the selection of the mating material is also important, and especially when the conditions are severe, the selection is more limited than the mating material. Under such circumstances, conventional sliding materials are relatively good when the mating material is Cr steel, Mn steel, etc., but when used with spheroidal graphite cast iron, the sliding properties are poor and it is unsuitable as a mating material. Become. however,
It has been confirmed that the shoe material made of the Cu alloy according to the present invention can withstand even when the mating material is spheroidal graphite cast iron. In addition, according to the studies of the present inventors, the thermal conductivity required for a shoe material that can be used in a swash plate type compressor for a high-performance car cooler is 0.2 cal/cm ³ .
It is desirable that the temperature is sec・℃ or higher, and
It is more preferable that the hardness is 0.4 cal/cm ²・sec・℃ or more, and even if the hardness is 300℃
It has become clear that it is desirable to have a Vickers hardness (Hv) of 80 or more at high temperatures, and all Cu alloys according to the present invention have such desirable thermal conductivity and hardness, This results in excellent effects. Next, preferable alloy structures according to the present invention include those in which Pb and at least one of Cr, Ti, and Zr are added to Cu. By adding Pb, a material with improved conformability and good sliding properties under boundary lubrication can be obtained.
When one or more precipitate additive elements are added (for example, when Ti and Pb are added to Cu), the above-mentioned
In addition to the effect of Pb, the mechanical strength improvement effect by refining the structure, which is a characteristic of precipitate additive elements, results in a more stable coefficient of friction at higher temperatures, which in turn results in materials that are less likely to seize. You can get it. In this case, the preferred range of addition ratios is group a and group a element Ti,
The total amount of one or more of Cr, Zr, etc. is 0.3~
2.0%, Pb is 5-10%. In addition, when Sn is further added to the combination of these elements (that is, an alloy in which Ti, Pb, and Sn are added to Cu), Sn is extremely easy to form a solid solution in Cu. In addition to the effects of Cu alloys, it is possible to obtain a Shu material that has sufficient mechanical strength, is more stable even at high temperatures, and has a lower coefficient of friction. In this case, the preferred range of addition ratios is 0.3 to 2% in total of group a and one or more of group a elements such as Ti, Cr, Zr, etc., 5 to 10% of Pb, and Sn is 1~
It is 3%. It is also effective to add Sn and to improve castability. As a result, the following effects can be recognized in the Cu alloy according to the present invention. In other words, since the amount of added elements is significantly smaller than that of conventional shoe materials, it has good thermal conductivity and can easily dissipate the frictional heat generated even in long periods without lubrication. There is no softening of the material, which makes it less likely to cause seizure.
In addition, in the case of the present invention, there are fewer additive elements for strengthening compared to conventional materials, so at first glance it seems that sufficient strengthening is not achieved compared to conventional materials. We attempted to solve the problem of seizure caused by poor heat dissipation due to the large amount of Pb (20 to 40%) by adding a large amount of Pb, and therefore Although it was somewhat superior at room temperature, the overall strength was lower.
On the other hand, in the present invention, the number of reinforcing additive elements is small, but the conformability improving material (elements) is also small, so as a result, there is not much difference in strength compared to conventional materials. Moreover, especially at high temperatures, the copper alloy of the present invention exhibits better values than conventional materials. Furthermore, in the present invention, there is a small amount of conformability improving material, and in addition, Sn has a small decrease in hardness even at high temperatures.
Due to the addition of solid solution elements, the strength and hardness of the matrix do not decrease even when the shoe becomes high temperature due to frictional heat, etc., and is in an extremely stable state. Therefore, this extremely stable matrix state Therefore, the compatibility-improving effect of Pb, etc., which is uniformly dispersed, can be more effectively exerted. The Cu alloy of the present invention also contains nickel (Ni), iron (Fe), tellurium (Te),
Phosphorus (P), antimony (Sb), arsenic (As), etc. can be added in small proportions, and this mainly has the effect of improving strength or making the matrix finer, but these do not affect the effect of addition. It has its advantages and disadvantages, and it has been confirmed that its performance is considerably lower than that of Cr, Zr, Ti, Pb, and Sn. However, it has been confirmed that it can withstand use under certain conditions. Below, specific examples of the present invention will be shown in order to further facilitate understanding of the present invention. First, samples 1 to 5 were obtained by a casting method using the composition ratios shown in Table 1. The casting method is approximately 1250℃.
A method was adopted in which Cu was added, followed by alloying elements (Cr, Zr, Ti, Sn), and the resulting material was heat-treated at approximately 700°C for 2 hours to prevent segregation to obtain a Cu alloy material. In order to conduct actual machine tests using these materials, each was processed to a diameter of 18 mm and a thickness of 4.5 mm to obtain a shoe. Further, this shoe has a spherical concave surface with a depth of about 3 mm so that a part of a ball with a diameter of about 14 mm is inscribed in the center. Incidentally, samples 10 to 17 having the alloy compositions shown in Table 2 were prepared as comparative materials by the same method as above, and samples 10 to 17 according to the present invention were prepared.
A comparison was made between Cu alloy and Shu. In addition, the hardness of Samples 1 to 5 at the time of final processing at room temperature was all Hv100 or higher. Furthermore, the thermal conductivity of each of the obtained samples was measured and shown in Table 3. As is clear from the sample table, each sample made of the Cu alloy of the present invention had excellent thermal conductivity. -ing

【table】

【table】

[Table] Experiment 1 Using each sample in Tables 1 and 2, an experiment was conducted to measure the friction coefficient and the exothermic temperature at that time. The measurement method was to rotate a disc, press a shoe against it, and gradually increase the pressing load while measuring the coefficient of friction and the heat generation temperature of the shoe.

[Table] The results obtained are shown in Figures 2 and 3. In addition,
Figures 2 and 3 are part of the experimental results. Similar results were obtained for other samples 1, 3, and 5, although the performance was somewhat lower than that of samples 2 and 4. As is clear from FIG. 2, the sample based on the present invention has a lower coefficient of friction in all regions than the comparative material, and is stable even when the load is increased. Also, looking at the heat generation temperature of the shoe from Figure 3,
In the case of the sample according to the present invention, compared to the comparative sample,
It is declining in all areas. Furthermore, when these results are compared with the thermal conductivity of each sample in Table 3, all the samples of the present invention having a thermal conductivity above a certain level are good. Based on these facts, if the load is increased, the frictional resistance will naturally increase and heat will be generated.This heat generation will change the structure of the material, and the increase in the coefficient of friction will cause seizures.Thermal conduction Although this occurs in comparison samples with poor performance, even if heat is generated in the samples of the present invention, it has excellent heat dissipation properties, so the temperature of the entire shoe or the temperature near the sliding surface does not rise too much. Therefore, there are no phenomena such as structural changes or increases in the coefficient of friction, and it is stable in all areas. What is particularly noteworthy here is that although the oil lubrication was not sufficient, the samples of the present invention performed well, which is of great significance. Experiment 2 Next, an actual machine test was conducted under the most severe conditions for lubricating oil supply, and the results are shown in Table 4. The test conditions are as follows. (1) Compressor Swash plate type compressor (total displacement 150c.c.) (2) Rotation speed 4000r.pm (3) Discharge side gas pressure Pd = 4 to 5Kg/cm ² (4) Suction side gas pressure Ps = approx. 50mmHg (5) Operating time 20Hrs (6) Lubricating oil Refrigerator oil 150c.c. (7) Compatible material Spheroidal graphite cast iron (8) Gas amount 100g (approx. 10% of regular)

[Table] As is clear from Table 4, all of the samples according to the present invention showed no seizure at all and were all in good condition. In particular, since this experiment was performed under the most severe lubrication conditions that occur under normal operating conditions, the fact that it was satisfactory even under such conditions is proof of the superiority of the Cu alloy sample according to the present invention. It is. Experiment 3 Next, as a load life experiment, an experimental test was conducted under conditions that particularly tend to cause poor lubrication, and the results are shown in Table 5. The test conditions are as follows. (1) Compressor Swash plate compressor (total displacement 150c.c.) (2) Rotation speed 5500r.pm (3) Discharge side gas pressure Pd=20Kg/cm ² (4) Suction side gas pressure Ps=3Kg/cm ² (5) Operating time 400Hrs (6) Lubricating oil and amount Refrigerator oil 150c.c. (7) Continuous operation 25 seconds operation, 5 seconds rest (8) Compatible material Spheroidal graphite cast iron (9) Gas amount 1Kg

[Table] As is clear from Table 5, sample 1 according to the present invention
It was found that Samples No. 5 to No. 5 had no seizure phenomenon and had less wear than Comparative Samples Nos. 10 to 17, and were sufficiently usable. Since this experiment was conducted in a situation where almost no lubricating oil was present, the fact that it performed well indicates that seizure is unlikely. As detailed above, the present invention provides a compressor,
Particularly in swash plate type compressors for car coolers, lubricating oil is extremely low, and even if sufficient oil is not supplied to the sliding parts of the swash plate and shoe, or even if there is no lubrication for several minutes, the sliding properties of the mating material will improve. Even if the material is made of spheroidal graphite cast iron, which has poor wear and tear, it can withstand use for an extremely long time by using a shew material made of a specific Cu alloy that has little wear and tear and excellent thermal conductivity. This invention has great significance in that it provides a swash plate type compressor with a long life, and it has contributed greatly to improving the performance of compressors for car coolers in particular.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view for explaining the swash plate type compressor, and FIGS. 2 and 3 are graphs showing the friction coefficient and heat generation temperature results obtained in Experiment 1, respectively. 1: Cylinder block, 2: Cylinder bore,
3: Piston, 4: Shaft, 5: Swash plate, 6: Shoe, 7: Ball.

Claims (1)

[Scope of Claims] 1. A swash plate that is rotated by a rotating shaft within a cylinder block, and a piston that is moored to the swash plate via a shoe, and as the swash plate rotates, the piston moves into the cylinder bore. In the swash plate type compressor, the swash plate is mainly made of copper, and one or more elements selected from the group consisting of Group A elements and Group A elements of the periodic table. A swash plate compressor comprising a copper alloy containing the following elements in a total amount not exceeding 3% and further containing 0.5 to 15% lead. 2 It has a swash plate that is rotated by a rotating shaft within a cylinder book, and a piston that is moored to the swash plate via a shoe, and the piston reciprocates around the cylinder borer as the swash plate rotates. In the swash plate type compressor, the shoe is mainly made of copper, and contains a total of 3 or more elements selected from the group consisting of elements of Group A and Group A of the periodic table. %, and further contains 0.5 to 15% lead and 5% lead.
A swash plate type compressor characterized in that it is made of a copper alloy containing less than or equal to tin.