JP2008169787A - Sliding member for compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor sliding member having a base material principally composed of aluminum and a sliding layer, which is formed on the surface of the base material by an electroless plating method and principally composed of nickel while containing phosphorus and can exhibit higher adherence and crack resistance, for improving durability of a compressor. <P>SOLUTION: The shoe 21 of this invention is formed of the base material 21a and a sliding layer 21b formed on the surface of the base material 21a by an electroless plating method. The base material 21a is formed of a material principally composed of aluminum. The sliding layer 21b is principally composed of nickel and contains phosphorus and at least one of indium and thallium. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sliding member for a compressor.

  Patent Document 1 discloses a conventional compressor sliding member. This sliding member for a compressor is formed by a base material made of a material mainly composed of aluminum and an electroless plating method on the surface of the base material, and is composed mainly of nickel (Ni) and phosphorus (P). Including a sliding layer.

  This sliding member for a compressor can be embodied in a shoe of a swash plate type compressor. For example, the shoe of a swash plate compressor has a substantially hemispherical shape, and the hemispherical surface exhibits excellent slidability with respect to a piston seat, and the substantially flat surface is in contact with the front and rear surfaces of the swash plate. Excellent slidability.

JP 2003-161259 A

  However, a large load can act on the sliding member for the compressor in the shear direction and the vertical direction because the compressor can be driven at a high speed. And the operating environment of the compressor has become increasingly severe in recent years, such as driving the compressor at a higher speed. For this reason, the sliding member for compressors is required to exhibit superior adhesion and crack resistance compared to conventional sliding layers.

  That is, if a large load acts on the sliding layer of the sliding member for a compressor in the shear direction, the sliding layer is easily peeled off from the base material. When the substrate is made of a material mainly composed of aluminum, it is necessary to consider the followability of the sliding layer due to deformation of the substrate. For this reason, the sliding layer is required to have excellent adhesion. In addition, when foreign matter such as wear powder is present between the mating material, a large load is locally applied to the sliding layer in the vertical direction, and the sliding layer may be cracked. For this reason, the sliding layer is also required to have excellent crack resistance.

  The present invention has been made in view of the above-described conventional situation, and is formed of a base material made of a material mainly composed of aluminum, and the surface of the base material by an electroless plating method. In the sliding member for a compressor having a sliding layer containing phosphorus, an object to be solved is to make the sliding layer capable of exhibiting better adhesion and crack resistance. And it is also made into the problem which should be solved to raise the durability of a compressor more by this sliding member for compressors.

  The inventors have intensively studied to solve the above problems, and in order to improve the adhesion and crack resistance of the sliding layer, the sliding layer may contain at least one of indium and thallium. It was discovered that it was necessary and the present invention was completed.

  That is, the sliding member for a compressor of the present invention includes a base material made of a material containing aluminum as a main component, and a slide formed on the surface of the base material by an electroless plating method, containing nickel as a main component and containing phosphorus. In the sliding member for a compressor having a moving layer, the sliding layer includes at least one of indium and thallium.

  The sliding layer disclosed in Patent Document 1 includes boron (B) in addition to phosphorus, and boron, together with aluminum (Al), gallium (Ga), indium (In), and thallium (Tl), group 3 (3B) in the periodic table. Belonging to. For this reason, it is expected that the sliding layer containing boron is preferably in close contact with a base material mainly composed of aluminum of the same family. According to the test results of the inventors, the sliding layer containing at least one of indium and thallium not only exhibits excellent adhesion with a base material mainly composed of aluminum of the same family, but also excellent. Demonstrate crack resistance.

  Therefore, this sliding member for a compressor is embodied in a shoe or the like of a swash plate type compressor and exhibits excellent durability.

  U.S. Pat. No. 3,674,447 discloses a sliding layer containing phosphorus and thallium in addition to nickel. However, this document does not consider the adhesion between the sliding layer and the base material, and only discloses that the sliding layer is formed on a base material containing iron (Fe) as a main component.

  Japanese Patent Laid-Open Nos. 2003-268558 and 2005-194562 disclose plating baths containing indium and thallium. However, these documents only disclose that the plating bath is stabilized by adding indium or the like to the plating bath.

  A base material consists of material which has aluminum as a main component, such as A4032, AC3A, ADC1.

  The sliding layer is formed on the surface of the substrate by an electroless plating method. Employing the electroless plating method is advantageous in manufacturing because it is possible to form a sliding layer having a suitable thickness only by performing post-processing such as barrel polishing, and it is difficult to waste the sliding layer. According to the knowledge of the inventors, the thickness of the sliding layer is suitably 5 to 100 μm.

  The sliding layer is mainly composed of nickel, contains phosphorus, and contains at least one of indium and thallium. According to the test results of the inventors, it is preferable that the sliding layer has 0.05% by mass or more of thallium and the balance is substantially nickel. In the present specification, “substantially” means that unavoidable impurities can be included. In particular, it is preferable that the sliding layer has a thallium content of 3.00% by mass or less and the balance is substantially nickel.

  When thallium is 0.05% by mass or more, the crack generation load is sufficiently large and excellent adhesion is exhibited. If thallium exceeds 3.00% by mass, the adhesion decreases. Moreover, when thallium exceeds 3.00 mass%, slidability will also fall.

  Further, according to the test results of the inventors, it is also preferable that the sliding layer has 0.01% by mass or more and 1.00% by mass or less of indium, and the balance is substantially nickel. In this case, if indium is 0.01% by mass or more and 1.00% by mass or less, the crack generation load is sufficiently large and excellent adhesiveness is exhibited. Even if the electroless plating bath is configured so that indium is 3.00% by mass or more, the sliding layer does not adhere to the substrate.

  In the sliding layer, indium is 0.01% by mass or more and 1.00% by mass or less, thallium is 0.01% by mass or more and 3.00% by mass or less, and the balance is substantially nickel. It is also preferable that there is. In this case, the crack generation load is sufficiently large and exhibits excellent adhesion.

  The sliding layer preferably contains phosphorus in an amount of 4% by mass or less. A sliding layer containing no phosphorus cannot be formed by electroless plating. When hypophosphorous acid is reduced to produce phosphorus, it is also difficult to reduce phosphorus to 0.5% by mass or less.

  Further, a sliding layer made of Ni-P was formed on a base material made of an aluminum alloy by an electroless plating method, and the relationship between the phosphorus content (% by mass) and the hardness (Hv) of the sliding layer was determined. However, the results in Table 1 were obtained.

  As is apparent from Table 1, a sliding layer in which phosphorus exceeds 4% by mass, more precisely, 3.8% by mass has a reduced hardness and is likely to be deformed during long-term use, causing a practical problem.

  First, a variable displacement swash plate compressor in which the compressor sliding member of the embodiment is embodied as a shoe will be described. As shown in FIG. 1, the compressor has a front housing 2 joined to the front end of the cylinder block 1 and a rear housing 4 joined to the rear end of the cylinder block 1 via a valve unit 3. . The cylinder block 1 and the front housing 2 are provided with shaft holes 1a and 2a extending in the axial direction, and a drive shaft 5 is rotatably supported in the shaft holes 1a and 2a via bearings or the like. . Note that the left side in FIG. 1 is the front side, and the right side is the rear side.

  The inside of the front housing 2 is a crank chamber 6. In the crank chamber 6, a lug plate 7 is fixed to the drive shaft 5 through a bearing device between the crank chamber 6 and the front housing 2. Further, a swash plate 8 is provided in the crank chamber 6 behind the lug plate 7. The swash plate 8 is inserted through the drive shaft 5, and the inclination angle is changed by the link mechanism 9 provided between the swash plate 8 and the lug plate 7 in this state.

  The cylinder block 1 is provided with a plurality of cylinder bores 1b extending concentrically extending in the axial direction. A single-headed piston 10 is accommodated in each cylinder bore 1b so as to be able to reciprocate. The side of the crank chamber 6 of each piston 10 is a neck portion, and a receiving seat 10a that is recessed in a spherical shape is provided on the neck portion of each piston 10 so as to face each other.

  A pair of front and rear shoes 21 is provided between the swash plate 8 and each piston 10. As shown in FIG. 2, each shoe 21 has a substantially hemispherical shape, the hemispherical surface of each shoe 21 abuts on the receiving seat 10 a of the piston 10, and the substantially flat surface abuts on the front and rear surfaces of the swash plate 8. Yes.

  Each shoe 21 includes a substantially hemispherical base material 21a made of A4032, and a sliding layer 21b formed on the surface of the base material 21a by an electroless plating method. The sliding layer 21b contains nickel as a main component, contains phosphorus, and contains at least one of indium and thallium.

  As shown in FIG. 1, the rear housing 4 is formed with a suction chamber 4a and a discharge chamber 4b. The cylinder bore 1 b can communicate with the suction chamber 4 a via the suction valve mechanism of the valve unit 3 and can communicate with the discharge chamber 4 b via the discharge valve mechanism of the valve unit 3.

  A capacity control valve 11 is accommodated in the rear housing 4. The capacity control valve 11 communicates with the suction chamber 4a through the detection passage 4c, and connects the discharge chamber 4b with the crank chamber 6 through the air supply passage 4d. The capacity control valve 11 detects the pressure in the suction chamber 4a, thereby changing the opening degree of the air supply passage 4d and changing the discharge capacity of the compressor. The crank chamber 6 and the suction chamber 4a communicate with each other through an extraction passage 4e. A condenser 13, an expansion valve 14 and an evaporator 15 are connected to the discharge chamber 4 b by a pipe 12, and the evaporator 15 is connected to the suction chamber 4 a by a pipe 12.

  A pulley 16 is rotatably provided at the front end of the front housing 2 via a bearing device, and the pulley 16 is fixed to the drive shaft 5. A belt 18 that is rotationally driven by an engine 17 is wound around the pulley 16.

  The shoe 21 is manufactured as follows. First, a substantially hemispherical base material 21a is prepared by casting, cutting and forging.

  On the other hand, a plating bath in which Ni supply source is nickel sulfate, reducing agent is hypophosphorous acid, complexing agent is malic acid, pH adjusting agent is sodium hydroxide, indium supply source is indium nitrate, and thallium supply source is thallium nitrate. prepare. The plating bath has a Ni concentration of 25 g / L, a pH of 6.2, and a temperature of 82 ° C.

  And the base material 21a is immersed in the plating bath which adjusted the amount of indium nitrate and / or thallium nitrate for a predetermined time, and after taking out, it wash | cleans with water. Thereafter, barrel polishing is applied to the entire surface. In this way, as shown in FIG. 2, the sliding layer 21b having a thickness of 5 to 100 μm is formed on the base material 21a by the electroless plating method, and the shoe 21 is obtained.

  In the compressor configured as described above, the swash plate 8 rotates synchronously when the drive shaft 5 shown in FIG. 1 rotates, and the piston 10 reciprocates in the cylinder bore 1 b via the shoe 21. Thereby, the volume of the compression chamber formed on the head side of the piston 10 changes. For this reason, the refrigerant gas in the suction chamber 4a is sucked into the compression chamber and compressed, and then discharged into the discharge chamber 4b. In this way, the refrigeration operation is performed by the refrigeration circuit including the compressor, the condenser 13, the expansion valve 14, and the evaporator 15. During this time, the shoe 21 exhibits excellent slidability between the hemispherical surface and the receiving seat 10 a of the piston 10, and an approximately flat surface between the front and rear surfaces of the swash plate 8. Demonstrate.

  In order to evaluate the durability of the compressors of the examples, the following crack resistance evaluation test and adhesion evaluation test were performed.

(Crack resistance evaluation test)
A specimen is prepared in which a sliding layer is formed on a plate-like test piece made of the same material as the base material 21a by the electroless plating method in the same manner as described above. In addition, a nanotech scratch tester having an indenter of 0.2R diamond is prepared.

  The indenter was moved at a speed of 10 mm / min while gradually increasing the load at 100 N / min with respect to the specimen, and cracks in the sliding layer of the specimen were observed (n = 2). The maximum load was 200N.

(Adhesion evaluation test)
A shoe 21 having a sliding layer 21b formed by electroless plating is prepared in the same manner as described above. Then, as shown in FIG. 3, the shoe 21 is bonded to the iron plate 71 with an adhesive (“Araldite Powder AT-1” manufactured by Ciba-Geigy Japan), and the iron plate 71 is sheared while fixing the shoe 21 with the fixing jig 72. Pulled on. When the adhesive layer was peeled off from the iron plate 71 (about 60 N), the adhesion was evaluated as ◯, and when the sliding layer 21b was peeled off from the shoe 21, the adhesion was marked as x.

  Table 2 shows the relationship between the thallium content (% by mass), the cracking load (N), and the adhesiveness when the sliding layer 21b does not contain indium but contains thallium in various proportions. Table 3 shows the relationship between the indium content (% by mass), the crack generation load (N), and the adhesiveness when the sliding layer 21b does not contain thallium but contains indium in various proportions. Show. Furthermore, when the sliding layer 21b contains indium at 0.01% by mass and thallium is contained in various proportions, the relationship between the thallium content (% by mass) and the crack generation load (N) is as follows. Table 4 shows.

  From Table 2, it can be seen that the sliding layer 21b not containing indium exhibits excellent crack resistance when thallium is 0.05% by mass or more. Further, since the adhesiveness of the sliding layer 21b containing 5.00% by weight of thallium is lowered, the sliding layer 21b also exhibits excellent adhesiveness if the thallium is 3.00% by weight or less. is doing.

  Moreover, it can be seen from Table 3 that the sliding layer not containing thallium exhibits excellent crack resistance and adhesion when indium is 0.01 mass% or more and 1.00 mass% or less. When indium exceeded 1.00% by mass, the adhesion was also slightly lowered. Moreover, when indium was 3.00 mass%, the sliding layer did not adhere to the substrate.

  Furthermore, it can be seen from Table 4 that if the sliding layer containing indium and thallium has a thallium content of 0.01 mass% or more and 3.00 mass% or less, the crack generation load is sufficiently large. In addition, it is clear from Table 3 that when the indium content is 0.01% by mass or more and 1.00% by mass or less, the crack generation load is sufficiently large and excellent adhesiveness is exhibited. Moreover, it turns out that a big improvement in cracking resistance is seen by less thallium content by containing 0.01 mass% of indium compared with Table 2.

(Slidability evaluation test)
A slidability evaluation test was also conducted. At this time, as shown in FIG. 4, a shoe 21 in which a sliding layer is formed by an electroless plating method as described above and a swash plate specimen 88 simulating the swash plate 8 are prepared. The swash plate specimen 88 is obtained by forming a sliding layer 88b containing MoS ₂ on the upper surface of a base material 88a of the same type as the swash plate 8. The surface of the sliding layer 88b constitutes a flat sliding surface 88c on which each shoe 21 slides. The shoe 21 is placed so that a substantially flat surface is brought into contact with the sliding layer 88 b of the swash plate specimen 88. Then, the shoe 21 is pressed against the swash plate specimen 88 with a predetermined load by the pressing jig 99 in which the shoe seat 38 a corresponding to the hemispherical surface of the shoe 21 is recessed. In this way, the swash plate specimen 88 and the shoe 21 are in contact with each other, and the swash plate specimen 88 is rotated under the conditions of a peripheral speed of 7.8 m / sec, a load of 5800 N, and a refrigerator oil of 75 mg / min. The time until seizure occurred was measured.

  When the thallium exceeds 3.00% by mass, the sliding layer 21b not containing indium showed a tendency to decrease in slidability. Moreover, the sliding layer which does not contain thallium showed the same tendency when indium exceeded 1.00 mass%.

  From the above confirmation, it can be seen that the compressor sliding member of the example improves the durability of the variable displacement swash plate compressor.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments and can be appropriately modified and applied without departing from the spirit thereof.

  The sliding member for a compressor of the present invention can be used for a shoe of a swash plate compressor, a vane of a vane compressor, a movable scroll of a scroll compressor, or the like.

The compressor may use a CO ₂ refrigerant in addition to a general refrigerant such as R134a. In particular, when CO ₂ is used as the refrigerant, the effects of the present invention can be remarkably enjoyed. This is because when CO ₂ is a refrigerant, the pressure at the time of compression becomes a very high pressure of about 15 MPa, and the compression reaction force becomes very high. Further, CO ₂ as a refrigerant has a very low lubrication performance compared with other general refrigerants even if a lubricating component is added.

It is a longitudinal cross-sectional view of the capacity | capacitance variable swash plate type compressor which materialized the sliding member for compressors of the Example in the shoe. It is an expanded sectional view of a shoe of an example. It is sectional drawing which shows the method of an adhesive evaluation test. It is sectional drawing which shows the method of a slidability evaluation test.

Explanation of symbols

21 ... Shoe (sliding member for compressor)
21a ... base material 21b ... sliding layer

Claims (6)

In a sliding member for a compressor having a base material made of a material containing aluminum as a main component and a surface of the base material formed by an electroless plating method, and having a sliding layer containing nickel as a main component and containing phosphorus,
The sliding member for a compressor, wherein the sliding layer contains at least one of indium and thallium.   2. The sliding member for a compressor according to claim 1, wherein the sliding layer has a thallium content of 0.05% by mass or more and the balance is substantially nickel.   The sliding member for a compressor according to claim 2, wherein the thallium is 3.00 mass% or less.   2. The sliding member for a compressor according to claim 1, wherein the sliding layer contains 0.01 mass% or more and 1.00 mass% or less of indium, and the balance is substantially nickel.   In the sliding layer, indium is 0.01% by mass or more and 1.00% by mass or less, thallium is 0.01% by mass or more and 3.00% by mass or less, and the balance is substantially nickel. The sliding member for a compressor according to claim 1.   The sliding member for a compressor according to any one of claims 1 to 5, wherein the sliding layer contains 4 mass% or less of phosphorus.

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