JP2010084821A - Bearing structure of rotary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide bearing structure of a rotary machine capable of preventing damage due to a heat load applied when starting and stopping the rotary machine and a high-load condition of the rotary machine, having excellent sliding characteristics, stabilized in strength, and capable of improving reliability of a bearing. <P>SOLUTION: Bearing structure of a rotary machine, which pivotally supports a rotor 11 of the rotary machine, is structured by laminating metal layers 16A and 16B, intermediate layers 20A and 20B and DLC layers 19A and 19B in order on inside surfaces 14A and 14B of bearing base metals 12A and 12B. The bearing base metal is a structural steel and a soft Fe group metal. The metal layer is formed from Cu, Al or a Cu-based or Al-based alloy. The intermediate layers have first intermediate layers 17A and 17B and second intermediate layers 18A and 18B connected to the DLC layers, and the first intermediate layer is mainly composed of Cr. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a bearing structure of a rotating machine that supports a rotor such as a rotor in a rotating machine such as a generator and a turbine, and more particularly to a bearing structure of a rotating machine that can withstand frequent start / stop and high load conditions.

  Since rotating machines such as generators and turbines are heavy and rotate at high speed, a rotor such as a rotor is usually supported by a bearing for high load and high rotation. This bearing has a structure in which a bearing alloy (bearing metal) called white metal is lined by casting on the inner surface of a bearing base made of structural steel divided into two in the circumferential direction. It has become. Since this bearing metal is moderately soft and excellent in wear resistance, it is widely used not only for power generation equipment but also for ships.

  Conventionally, a thermal power plant combining a boiler, a generator, and a turbine has been operated as a base power and has been operated in a steady state for a long period of time. However, in recent years, nuclear power plants have become base power, and thermal power plants tend to be used more frequently for load adjustment. As a result, thermal power plants change to operations that are repeatedly started and stopped on a daily basis, and the bearing metal of the bearings is repeatedly subjected to the thermal stress associated with starting and stopping, and there is also an event that causes damage due to thermal fatigue. It is supposed to occur.

  As a method for reducing the thermal stress acting on such a bearing metal, in Patent Document 1, as shown in FIG. 9, between the bearing base metal 101A, 101B made of structural steel and the bearing metal 102A, 102B, Copper layers 103A and 103B having an intermediate thermal expansion coefficient between the bearing metal and the structural steel are provided. According to the bearing 100 of this structure, it is possible to reduce the thermal stress acting on the bearing metals 102A and 102B.

  Further, in Patent Document 2, as shown in FIG. 10, the bearing metal 106 is attached to the pad base metal 105 that is point-supported by using the pivot 104 on the bearing base metals 101A and 101B. In this way, the thermal stress acting on the bearing metal 106 is reduced. According to the bearing 107 of this structure, the temperature of the bearing metal 106 can be reduced by the stress acting on the bearing metal 106 due to the thermal stress deformation of the entire bearing and the improvement of the cooling efficiency by the pad base metal 105.

  In the bearing 100, sliding surfaces 109 and 110 are formed on the inner side of the bearing metals 102A and 102B, and on the inner side of the bearing metal 106 in the bearing 107, and are in sliding contact with the rotor 108 via lubricant.

  On the other hand, Patent Documents 3 to 6 disclose bearings using diamond-like carbon (DLC) that is excellent in low friction, wear resistance, and heat resistance instead of bearing metal.

  The bearing described in Patent Document 3 is configured by providing a Cu-based or Al-based soft metal on a surface layer of a bearing base metal, and sequentially laminating a Ni layer, a Cr layer, and a DLC layer on the surface.

  The bearing described in Patent Document 4 is configured by sequentially laminating a hard ceramic layer such as TiAlN, a hard intermediate layer such as Ti or Cr, and a DLC layer on the surface of the bearing base.

  The bearing described in Patent Document 5 is configured by sequentially laminating a hard metal layer such as TiN or TiC and a DLC layer on the surface of a bearing base.

The bearing described in Patent Document 6 has a structure in which a hard metal layer such as Cr or W, a hard composite layer composed of metal and C constituting this metal layer, and a DLC layer are sequentially laminated on the surface of the bearing base metal. Has been.
JP 2005-337396 A JP 2006-234147 A JP 2004-76756 A JP 2001-316800 A JP 2000-8155 A JP 2007-127263 A

  Incidentally, in the bearing 100 described in Patent Document 1 shown in FIG. 9, although the thermal stress acting on the bearing metals 102A and 102B can be reduced by the interposition of the Cu layers 103A and 103B, the bearing metals 102A and 102B have remarkably high temperature strength. Since it is low, it is difficult to completely prevent the damage when it is subjected to many repeated cycles accompanying the start / stop of the rotating machine or exposed to high temperatures during long-term use.

  Further, in the bearing 107 described in Patent Document 2 shown in FIG. 10, although the cooling efficiency is increased by the pad structure and the temperature rise of the bearing metal 106 can be suppressed, the bearing metal 106 and the structural steel pad base metal 105 The thermal stress at the bonding interface due to the difference in thermal expansion cannot be sufficiently reduced.

  Further, in the bearings 100 and 107 described in Patent Documents 1 and 2, the characteristics of the bearing metals 102A, 102B, and 106 manufactured by the casting method are greatly affected by the casting conditions and the cooling conditions after casting, so that the strength varies. However, there is a problem that it is large and lacks reliability.

  Furthermore, as a result of detailed evaluation of the strength characteristics of the bearing metal by the present inventors, it was found that the strength of the bearing metal is very high in strain rate dependency. That is, the strain rate acting on the bearing metal is very slow based on the difference in thermal expansion that occurs between the bearing metal and the bearing base metal as the actual thermal power plant starts up, compared to the strain rate used in the normal strength test. . Since the strength of the bearing metal becomes lower as the strain rate becomes smaller, the strength characteristics of the ordinary bearing metal shown in various literatures, etc., under low strain rate conditions such as in an actual thermal power plant, It was found that the yield stress and elastic modulus both decreased to less than half.

  The bearing metal has a melting point of about 513 K (240 ° C.), and it is generally said that creep deformation occurs at a temperature exceeding 60% of the melting point. In the case of a bearing metal, 308K (35 ° C.) is 60% of the melting point, and it has been found that the plastic strain increases at low loads even near room temperature. That is, the damage mechanism of the bearing metal is caused by compressive plastic deformation at the start of the rotating machine, the amount of compressive plastic deformation increases even during the subsequent steady operation, and conversely, when the rotating machine is stopped, it undergoes tensile plastic deformation. I understand. It became clear that bearing metal was damaged by thermal fatigue by this repetition. The strength characteristics of the bearing metal as described above are difficult to improve because the base of the alloy is Sn.

  In the bearing described in Patent Document 3, since a soft Ni layer is interposed between the soft metal layer and the hard Cr layer on the surface of the bearing base metal, the DLC is applied when a high load is applied to the bearing. The deformation of the layer cannot be suppressed, and this DLC layer may be damaged.

  In the bearings described in Patent Documents 4 to 6, a hard layer is interposed between the bearing base and the DLC layer, but since no soft layer is provided, vibrations and impacts acting on the DLC layer are not generated. It is not absorbed and the DLC layer may be damaged by vibration or impact.

  In addition, soft metals such as Cu and Al have high thermal conductivity, so that heat generated in the DLC layer can be diffused well. However, since the soft metal layer does not exist in the bearings described in Patent Documents 4 to 6, the temperature increase of the DLC layer cannot be suppressed. As a result, the thermal stress of the DLC layer increases due to the thermal load associated with the start / stop of the rotating machine, and this DLC layer may be damaged.

  The object of the present invention has been made in consideration of the above-mentioned circumstances, and is excellent in sliding characteristics and strength without being damaged even with respect to thermal load and high load conditions accompanying start / stop of a rotating machine. It is an object of the present invention to provide a bearing structure for a rotating machine that can improve the reliability of the bearing by stabilizing it.

  The present invention is a bearing structure of a rotating machine that supports a rotor of a rotating machine, wherein a metal layer, an intermediate layer, and a diamond-like carbon layer are sequentially laminated on a base material, and the base material is structural steel, The metal layer is made of Fe-based metal such as mild steel, the metal layer is made of Cu, Al, or an alloy containing these as a main component, the intermediate layer is a first intermediate layer bonded to the metal layer, and the diamond-like carbon And a second intermediate layer bonded to the layer, wherein the first intermediate layer is mainly composed of Cr.

  According to the present invention, the portion in sliding contact with the rotor is not a bearing metal, but is a diamond-like carbon layer having excellent sliding properties (low friction, wear resistance and heat resistance), and Cu, Al, or A metal layer made of an alloy containing these as a main component absorbs vibrations and impacts acting on the diamond-like carbon layer to prevent damage to the diamond-like carbon layer, and further stabilizes the strength of the diamond-like carbon layer. Therefore, the reliability of the bearing can be improved.

  Further, since the thermal conductivity of the metal layer is high, it is possible to reduce the thermal stress by suppressing the temperature rise of the diamond-like carbon layer. As a result, the diamond-like carbon layer is also resistant to the thermal load associated with starting and stopping of the rotating machine. Damage to the carbon layer can be prevented.

  Furthermore, since the first intermediate layer is mainly composed of Cr that is harder than the metal layer, the deformation of the diamond-like carbon layer can be prevented even under high load conditions, and the damage can be prevented.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, the present invention is not limited to these embodiments.

[A] First embodiment (FIGS. 1 to 3)
FIG. 1 is a cross-sectional view showing a bearing to which a first embodiment of a bearing structure for a rotating machine according to the present invention is applied. FIG. 2 is a cross-sectional view schematically showing the structure of the sliding member in the bearing of FIG.

  A bearing 10 shown in FIG. 1 supports a rotor 11 as a rotor in a rotating machine such as a generator or a turbine with a lubricating oil (not shown) interposed therebetween, and is a bearing for high load and high rotation. It is. The bearing base as a base material of the bearing 10 has a substantially cylindrical shape, but is divided into two in the circumferential direction of the rotor 11, and the divided substantially semi-cylindrical bearing bases 12 </ b> A and 12 </ b> B are formed by bolts 13. It is concluded. The bearing bases 12A and 12B fastened by the bolt 13 allow the rotor 11 to pass through the lubricating oil by sliding members 15A and 15B (described later) provided on the inner arcuate inner surfaces 14A and 14B of the respective inner circular arc surfaces. Pivot. Here, each bearing base 12A and 12B is comprised from Fe-type metals, such as structural steel and mild steel.

  As shown in FIGS. 1 and 2, the sliding member 15A includes a metal layer 16A, a first intermediate layer 17A, a second intermediate layer 18A, and a diamond-like carbon layer (hereinafter simply referred to as DLC) on the inner surface 14A of the bearing base 12A. 19A) (hereinafter abbreviated as layers) are sequentially stacked. The sliding member 15B is configured by sequentially laminating a metal layer 16B, a first intermediate layer 17B, a second intermediate layer 18B, and a DLC layer 19B on the inner side surface 14B of the bearing base 12B. The first intermediate layer 17A and the second intermediate layer 18 constitute an intermediate layer 20A, and the first intermediate layer 17B and the second intermediate layer 18B constitute an intermediate layer 20B.

  The DLC layers 19A and 19B are excellent in sliding characteristics, that is, low friction, wear resistance, and heat resistance, and have high strength and high hardness (for example, Vickers height 2000 to 3000). As described above, since the DLC layers 19A and 19B have high strength, even if they are repeatedly subjected to thermal stress as the rotating machine is started and stopped, plastic deformation does not occur. Sliding surfaces 24A and 24B are formed on the inner sides of the DLC layers 19A and 19B so as to be in sliding contact with the rotor 11 through the lubricating oil. The DLC layers 19A and 19B are usually formed to a thickness of about 0.1 μm to 3 μm by a sputtering method or the like.

  The metal layers 16A and 16B are made of Cu, Al, or an alloy mainly containing these. As the alloy, a Cu—Cr alloy, a Cu—Cr—Zr alloy, a Cu—Be alloy, an Al—Si alloy, an Al—Si—Mg alloy, an Al—Si—Cu alloy, and the like are preferable. The metal layers 16A and 16B are formed to a thickness of about 1 to 3 mm on the inner side surface 14A of the bearing base metal 12A and the inner side surface 14B of the bearing base metal 12B by thermal spraying.

  The DLC layers 19A and 19B are excellent in low friction, wear resistance, and heat resistance, but are fragile and difficult to thicken, and thus are easily damaged by vibration and impact. Therefore, by providing the soft and highly ductile metal layers 16A and 16B, vibrations and shocks acting on the DLC layers 19A and 19B are absorbed and alleviated, and damage to the DLC layers 19A and 19B due to vibrations and shocks is prevented. The

  Further, since the metal layers 16A and 16B have high thermal conductivity, heat generated in the DLC layers 19A and 19B due to sliding with the rotor 11 can be efficiently released to the bearing base metals 12A and 12B and the lubricating oil. It becomes possible. Thereby, the temperature rise of the DLC layers 19A and 19B is suppressed, and the generation of thermal stress is reduced. As a result, damage to the DLC layers 19A and 19B is prevented even with respect to the thermal load associated with the start / stop of the rotating machine.

  In addition, since Cu alloy or Al alloy is harder and stronger than pure Cu or pure Al, it is effective when a large impact force acts on the DLC layers 19A and 19B. Even if a large impact force acts on the DLC layers 19A and 19B, the deformation is suppressed if the metal layers 16A and 16B are Cu alloy or Al alloy. Therefore, the DLC layers 19A and 19B are deformed from the metal layers 16A and 16B. The situation where it cannot be followed and it breaks is avoided.

  The first intermediate layers 17A and 17B are composed mainly of Cr, and the second intermediate layers 18A and 18B are composed mainly of at least one of W, Mo, and Ti. The first intermediate layers 17A and 17B and the second intermediate layers 18A and 18B are more ductile than the DLC layers 19A and 19B, and are harder than the metal layers 16A and 16B. Accordingly, even when a high load is applied to the DLC layers 19A and 19B, the deformation of the DLC layers 19A and 19B can be suppressed, so that the DLC layers 19A and 19B can be prevented from being damaged or separated.

  In addition, since the first intermediate layer 17A is composed mainly of Cr, the first intermediate layer 17A and the metal layers 16A and 16B have good adhesion because the first intermediate layer 17A is familiar with the metal layers 16A and 16B and is easily bonded. Can be increased. Furthermore, since W, Mo, and Ti constituting the second intermediate layers 18A and 18B are familiar and easily combined with the DLC layers 19A and 19B, the adhesion between the second intermediate layers 18A and 18B and the DLC layers 19A and 19B. Can be increased. The first intermediate layers 17A and 17B and the second intermediate layers 18A and 18B are formed to a thickness of about 0.5 μm to 5 μm by sputtering.

  Further, W, Mo, and Ti constituting the second intermediate layers 18A and 18B have smaller thermal expansion coefficients than the first intermediate layers 17A and 17B and the metal layers 16A and 16B, and are similar to the DLC layers 19A and 19B. Therefore, even if a thermal load is applied to the DLC layers 19A and 19B as the rotating machine is started and stopped, the thermal stress generated in the DLC layers 19A and 19B can be reduced, and damage such as cracks can be prevented.

  As shown in FIG. 1, the bearing base metals 12 </ b> A and 12 </ b> B are fastened using bolts 13. At this time, as shown in FIG. 3, the coupling surfaces 21A and 21B of the bearing base metals 12A and 12B come into contact with each other, but the sliding members 15A and 15B formed on the inner side surfaces 14A and 14B of the bearing base metals 12A and 12B. They are configured in a non-contact manner. That is, curved surfaces 22A and 22B having a radius of curvature R are formed at the inner ends of the coupling surfaces 21A and 21B in the bearing bases 12A and 12B. Since the curved surfaces 22A and 22B are formed continuously with the inner side surfaces 14A and 14B, sliding members 15A and 15B are formed on the curved surfaces 22A and 22B as well as the inner side surfaces 14A and 14B. Accordingly, portions of the sliding members 15A and 15B formed on the curved surface 22A of the bearing base 12A and the curved surface 22B of the bearing base 12B are brought into a non-contact state when fastened by the bolt 13.

  Thus, when the bearing members 12A and 12B are fastened by the bolts 13, the sliding members 15A and 15B are brought into a non-contact state, so that the distortion due to the thermal expansion of the sliding members 15A and 15B accompanying the start / stop of the rotating machine is caused. The absorbed thermal stress acting on the DLC layer 19A of the sliding member 15A and the DLC layer 19B of the sliding member 15B can be reduced, and the DLC layers 19A and 19B can be prevented from being damaged such as cracks.

  Next, a sliding test using the bearing 10 of the present embodiment will be described.

  In this test, pure Cu metal layers 16A and 16B are formed on the inner surfaces 14A and 14B of the bearing bases 12A and 12B made of structural steel by thermal spraying, and the first intermediate layer is formed on the surfaces of the metal layers 16A and 16B. A Cr layer as layers 17A and 17B and a W layer as second intermediate layers 18A and 18B are sequentially formed by sputtering, and DLC layers 19A and 19B are further formed by sputtering on the surfaces of second intermediate layers 18A and 18B. It was. The bearing bases 12A and 12B to which the sliding members 15A and 15B were applied in this way were fastened by the bolts 13 to obtain the bearing 10 (Example 1).

  A shaft 23 simulating the rotor 11 was inserted between the pair of bearings 10 and a sliding test was performed by rotating the shaft 23 in lubricating oil. At this time, a load is applied to the central portion of the shaft 23 to cause the surface pressure simulating an actual machine to act on the sliding members 15A and 15B of the bearing 10, and the surface pressure acting on the sliding members 15A and 15B is instantaneously applied. The test was carried out by changing the pressure to ½ times and 1.5 times the predetermined surface pressure. After the test, the presence or absence of damage occurring in the sliding members 15A, 15B, etc. was visually confirmed.

  A similar test was performed on the bearing 100 (Comparative Example 1) shown in FIG. 9 in which Sn-based bearing metals 102A and 102B were formed by centrifugal casting on the inner surfaces of the bearing bases 101A and 101B made of structural steel. A similar test was performed on the bearing 10 (Example 2) using a Cu alloy as the metal layers 16A and 16B and the bearing 10 (Example 3) using an Al-Mg-Si alloy.

  The test results are shown in Table 1. In Comparative Example 1 using the Sn-based bearing metals 102A and 102B, no abnormality was found on the sliding surface 109 of the bearing metals 102A and 102B until the number of repetitions of starting and stopping of the rotating machine was 200 cycles. In the cycle, remarkable plastic deformation marks were observed on the sliding surface 109.

  On the other hand, in Example 1, due to the effect of the metal layers 16A and 16B having excellent thermal conductivity, the temperature rise of the sliding surfaces 24A and 24B of the DLC layers 19A and 19B is suppressed, and the starting and stopping of the rotating machine is repeated. No damage such as peeling was observed in the DLC layers 19A and 19B up to 500 cycles, but damage due to peeling was observed in a part of the DLC layers 19A and 19B in 1000 cycles.

In Examples 2 and 3, by using a highly hard Cu alloy or Al alloy as the metal layers 16A and 16B, the DLC layers 19A and 19B can be applied to the DLC layers 19A and 19B even when the number of times of starting and stopping the rotating machine is 1000 cycles. It was found that no damage such as peeling was observed, and deformation of the DLC layers 19A and 19B could be suppressed.

  As described above, according to the present embodiment, the following effects (1) to (5) are obtained.

  (1) Since the portions in contact with the rotor 11 are the DLC layers 19A and 19B, they have excellent sliding characteristics such as low friction, wear resistance and heat resistance, are high in strength and stable, and are plastically deformed. Is unlikely to occur. Furthermore, since the metal layers 16A and 16B absorb and mitigate vibrations and shocks acting on the DLC layers 19A and 19B, damage to the DLC layers 19A and 19B due to vibrations and shocks can be prevented. From these things, the reliability of the bearing 10 can be improved.

  (2) Cu, Al constituting the metal layers 16A and 16B, or an alloy containing these as a main component has a significantly higher thermal conductivity than the conventional bearing metals 102A, 102B and 106, so that the DLC layers 19A and 19B By releasing the generated heat to the bearing bases 12A and 12B and the lubricating oil, the temperature rise of the DLC layers 19A and 19B can be suppressed, and the thermal stress generated in the DLC layers 19A and 19B can be reduced. Further, W, Mo, and Ti constituting the second intermediate layers 18A and 18B have smaller thermal expansion coefficients than the metal layers 16A and 16B and the first intermediate layers 17A and 17B, and are comparable to the DLC layers 19A and 19B. The generation of thermal stress in the DLC layers 19A and 19B can be suppressed. As a result, even if the heat load accompanying the start / stop of the rotating machine acts on the DLC layers 19A and 19B, the DLC layers 19A and 19B can be prevented from being damaged.

  (3) Since Cr constituting the first intermediate layers 17A and 17B and W, Mo and Ti constituting the second intermediate layers 18A and 18B are harder than the metal layers 16A and 16B, the bearing 10 has a high load. Since the deformation of the DLC layers 19A and 19B can be suppressed even under the conditions where the above acts, the peeling and damage of the DLC layers 19A and 19B can be prevented.

  (4) In the case where the metal layers 16A and 16B are Cu alloy or Al alloy harder than pure Cu or pure Al, the metal layers 16A and 16B are also formed even when a large impact force acts on the DLC layers 19A and 19B. Since it is difficult to deform, it is possible to prevent damage caused by the DLC layers 19A and 19B being unable to follow the deformation of the metal layers 16A and 16B.

  (5) When the bearing bases 12A and 12B are fastened by the bolts 13, the sliding members 15A and 15B of the bearing 10 are in a non-contact state, and therefore the heat of the sliding members 15A and 15B accompanying the start / stop of the rotating machine Distortion due to expansion is absorbed, thermal stress acting on the DLC layer 19A of the sliding member 15A and the DLC layer 19B of the sliding member 15B can be reduced, and damage such as cracks can be prevented in the DLC layers 19A and 19B.

[B] Second embodiment (FIGS. 4 and 5)
FIG. 4 is a cross-sectional view corresponding to FIG. 2 schematically showing the structure of the sliding member in the bearing to which the second embodiment of the bearing structure of the rotating machine according to the present invention is applied. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The bearing 25 of the present embodiment is different from the bearing 10 of the first embodiment in that instead of the second intermediate layers 18A and 18B mainly composed of W, Mo and Ti, TiC, TiN, TiCN, The second intermediate layer 26A, 26B made of ceramics containing at least one of SiC as a main component is provided.

  The ceramics of the second intermediate layers 26A and 26B are also easily familiar with the DLC layers 19A and 19B, and have high adhesion to the DLC layers 19A and 19B. Further, the ceramics constituting the second intermediate layers 26A, 26B are harder than W, Mo, Ti constituting the second intermediate layers 18A, 18B of the first embodiment. For example, the Vickers hardness is about 300 to 400 for W, Mo, and Ti, and about 1500 for the ceramics. Therefore, when the second intermediate layers 26A and 26B are used, the second intermediate layers 26A and 26B are not easily deformed even when a high load is applied to the DLC layers 19A and 19B, and thus the DLC layers 19A and 19B are not deformed. Peeling and damage are prevented.

  The second intermediate layers 26A and 26B are formed by sputtering together with the first intermediate layers 17A and 17B. In one embodiment, the second intermediate layers 26A and 26B are configured to have a continuous structure with respect to the first intermediate layers 17A and 17B. In this embodiment, the first intermediate layers 17A and 17B are coupled via the gradient composition layers 27A and 27B (FIG. 5). In the graded composition layers 27A and 27B, the composition ratio between Cr, which is the main component of the first intermediate layers 17A, 17B, and ceramics, which is the main component of the second intermediate layers 26A, 26B, gradually changes. The intermediate layer 17A, 17B gradually decreases toward the second intermediate layer 26A, 26B, and the ceramic gradually increases from the first intermediate layer 17A, 17B toward the second intermediate layer 26A, 26B.

  When forming the second intermediate layer 26A, 26B of one embodiment, three evaporators are installed in the same chamber, Cr is attached as a target to the first evaporator, and the target is attached to the second evaporator. C (carbon) is attached to the third evaporation device, for example, using Ti as a target. Next, the first evaporator is energized to evaporate Cr and deposit it on the surfaces of the metal layers 16A and 16B, thereby forming the first intermediate layers 17A and 17B. After the current supply to the first evaporator is cut off, the second and third evaporators are supplied to evaporate Ti and C, and TiC is deposited on the surfaces of the first intermediate layers 17A and 17B. Intermediate layers 26A and 26B are formed.

  As described above, the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B are continuously formed in the same chamber, so that Cr as the main component of the first intermediate layers 17A and 17B and the second intermediate layer are formed. 26A and 26B main component ceramics (for example, TiC) become a continuous structure, and the bond strength at the interface between them increases.

  When the second intermediate layers 26A and 26B are formed according to the other forms, first, as in the case of the one form, three evaporators are installed in the same chamber, and the first evaporator is used as a target. Cr is attached, C is attached as a target to the second evaporator, and Ti is attached as a target to the third evaporator. Next, the first evaporator is energized to evaporate Cr and deposit it on the surfaces of the metal layers 16A and 16B, thereby forming the first intermediate layers 17A and 17B.

  Next, the current and voltage to the first evaporator are gradually decreased, and the current and voltage to the second and third evaporators are gradually increased to evaporate Cr, Ti, and C together. The gradient composition layers 27A and 27B are formed by vapor deposition on the surfaces of the first intermediate layers 17A and 17B. Thereafter, the energization to the first evaporator is cut off, the rated energization to the second and third evaporators is performed to evaporate only Ti and C, and TiC is deposited on the surfaces of the gradient composition layers 27A and 27B. The second intermediate layers 26A and 26B are formed by vapor deposition.

  As described above, when the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B are formed in the same chamber, the gradient composition layers 27A and 27B are formed between the first intermediate layer 17A and the second intermediate layer 26A and 26B. It is possible to reduce the thermal stress caused by the difference in thermal expansion between the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B.

  Next, a sliding test using the bearing 25 of the present embodiment will be described.

  In this test, pure Cu metal layers 16A and 16B are formed on the inner surfaces 14A and 14B of the bearing bases 12A and 12B made of structural steel by thermal spraying, and the first intermediate layer is formed on the surfaces of the metal layers 16A and 16B. A Cr layer as layers 17A and 17B and a TiC layer as second intermediate layers 26A and 26B are sequentially formed by sputtering, and DLC layers 19A and 19B are further formed by sputtering on the surfaces of second intermediate layers 26A and 26B. It was. The bearing bases 12A and 12B to which the sliding members 15A and 15B were applied in this way were fastened by the bolts 13 to obtain a bearing 25 (Example 4).

  A sliding test was conducted by inserting a shaft 23 simulating the rotor 11 between the pair of bearings 25 and rotating the shaft 23 in lubricating oil. At this time, a load is applied to the central portion of the shaft 23 to cause the surface pressure simulating an actual machine to act on the sliding members 15A and 15B of the bearing 25, and the surface pressure acting on the sliding members 15A and 15B is instantaneously applied. The test was carried out by changing the pressure to ½ times and 2.0 times the predetermined surface pressure. After the test, the presence or absence of damage occurring in the sliding members 15A and 15B was visually confirmed.

  A similar test was performed when the graded composition layers 27A and 27B were formed between the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B (Example 5). Further, the same test was performed for Example 1 in which the second intermediate layer was W, and this was designated as Comparative Example 2.

  The test results are shown in Table 2. In this test, as a result of increasing the surface pressure acting on the sliding members 15A and 15B, the deformation amount of the sliding surfaces 24A and 24B of the DLC layers 19A and 19B increases, and the frictional heat causes the sliding surfaces 24A and 24B to be deformed. The temperature rises and the thermal stress becomes severe. As a result, in Comparative Example 2 in which W was used for the second intermediate layer, the DLC layers 19A and 19B were not damaged such as peeling until the number of repetitions of starting and stopping of the rotating machine was 200 cycles, but 500 cycles Then, damage due to peeling was observed in a part of the DLC layers 19A and 19B.

  On the other hand, in Example 4, the use of TiC that is harder than W and higher in rigidity as the second intermediate layers 26A and 26B suppresses deformation of the DLC layers 19A and 19B, and repeatedly starts and stops the rotating machine. No damage such as peeling was observed in the DLC layers 19A and 19B up to 500 cycles, but damage due to peeling was observed in a part of the DLC layers 19A and 19B in 1000 cycles.

In Example 5, as a result of reducing the thermal stress by forming the gradient composition layers 27A and 27B between the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B, It was found that even when the number of start / stop cycles was 1000 cycles, no damage such as peeling was observed in the DLC layers 19A and 19B, and deformation suppression and thermal stress reduction of the DLC layers 19A and 19B could be realized.

  According to this embodiment, in addition to the same effects (1), (2), (4) and (5) as in the above embodiment, the following effects (6) and (7) are obtained.

  (6) As the second intermediate layer, the second intermediate layers 26A and 26B, which are mainly composed of TiC, TiN, TiCN, and SiC and are harder than the second intermediate layers 18A and 18B, are formed. Even when a high load is applied to the layers 19A and 19B, the second intermediate layers 26A and 26B are not easily deformed, and as a result, peeling and damage of the DLC layers 19A and 19B can be prevented.

  (7) Cr is used as the first intermediate layers 17A and 17B, and hard ceramics mainly composed of TiC, TiN, TiCN, and SiC are used as the second intermediate layers 26A and 26B, and the first intermediate layers 17A and 17B Since the gradient composition layers 27A and 27B are formed at the boundaries between the second intermediate layers 26A and 26B, the thermal stress concentration at the boundaries between the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B is reduced. Even if the temperature of the sliding surfaces 24A and 24B of the DLC layers 19A and 19B rises due to an increase in the surface pressure acting on the sliding members 15A and 15B, the DLC layers 19A and 19B and the second intermediate layers 26A and 26B can be relaxed. Can be prevented from peeling.

[C] Third embodiment (FIG. 6)
FIG. 6 is a cross-sectional view corresponding to FIG. 2 schematically showing the structure of the sliding member in the bearing to which the third embodiment of the bearing structure of the rotating machine according to the present invention is applied. In the third embodiment, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description is simplified or omitted.

  The bearing 30 of the present embodiment is different from the bearings 10 and 25 of the first and second embodiments in that the first intermediate layers 17A and 17B mainly composed of Cr, TiC, TiN, TiCN, SiC The third intermediate layers 31A and 31B containing W, Mo and Ti as main components are formed between the second intermediate layers 26A and 26B containing as a main component.

  The third intermediate layers 31A and 31B have the same configuration as the second intermediate layers 18A and 18B of the first embodiment, and are formed on the surface of the first intermediate layer 17A by a sputtering method. The second intermediate layers 26A and 26B are formed by sputtering on the surfaces of the third intermediate layers 31A and 31B. At this time, as in the second embodiment, the second intermediate layers 26A and 26B are formed on the third intermediate layers 31A and 31B. On the other hand, in the case of a continuous structure, and in the case of the same continuous structure, the composition is formed through a gradient composition layer (not shown in FIG. 6) similar to the gradient composition layers 27A and 27B. There is.

  Next, a sliding test using the bearing 30 of the present embodiment will be described.

  In this test, pure Cu metal layers 16A and 16B are formed on the inner surfaces 14A and 14B of the bearing bases 12A and 12B made of structural steel by thermal spraying, and the first intermediate layer is formed on the surfaces of the metal layers 16A and 16B. A Cr layer as layers 17A and 17B, a W layer as third intermediate layers 31A and 31B, and a TiC layer as second intermediate layers 26A and 26B are sequentially formed by sputtering, and the surfaces of second intermediate layers 26A and 26B are further formed. DLC layers 19A and 19B were formed by sputtering. The bearing bases 12A and 12B to which the sliding members 15A and 15B were applied in this way were fastened by the bolts 13 to obtain a bearing 30 (Example 6).

  A shaft 23 simulating the rotor 11 was inserted between the pair of bearings 30 and a sliding test was performed by rotating the shaft 23 in lubricating oil. At this time, a load is applied to the central portion of the shaft 23 to cause the surface pressure simulating an actual machine to act on the sliding members 15A and 15B of the bearing 30, and the surface pressure acting on the sliding members 15A and 15B is instantaneously applied. Then, the temperature of the sliding surfaces 24A and 24B of the DLC layers 19A and 19B was increased by increasing the rotational speed of the shaft 23 to 1.2 times and changing the shaft pressure to 1/2 and 2.0 times the predetermined surface pressure. The test was carried out in the state. After the test, the presence or absence of damage occurring in the sliding members 15A and 15B was visually confirmed. A similar test was also performed when a gradient composition layer was formed at the boundary between the second intermediate layers 26A and 26B and the third intermediate layers 31A and 31B (Example 7). Further, the same test was performed for Example 4 as Comparative Example 3.

  The test results are shown in Table 3.

  In Example 4 using the hard ceramic TiC as the second intermediate layer 26A, 26B, as described in the second embodiment, it is good for the increase in the surface pressure acting on the sliding members 15A, 15B. Showed a good result. However, as shown in Comparative Example 3 in Table 3, the number of repetitions of starting and stopping of the rotating machine with respect to the temperature rise of the sliding surfaces 24A and 24B of the DLC layers 19A and 19B due to the increase in the rotational speed of the shaft 23 However, no damage such as peeling was observed in the DLC layers 19A and 19B up to 100 cycles. However, when the number of repetitions was 200 cycles or more, the DLC layers 19A and 19B and the second intermediate layers 26A and 26B were partially peeled off. Damage was observed.

In Example 6 in which W is provided as the third intermediate layers 31A and 31B, the third intermediate layers 31A and 31B having a small thermal expansion coefficient are replaced with the first intermediate layers 17A and 17B and the second intermediate layers 26A and 26B. Is provided between the first intermediate layer 26A and the second intermediate layer 26A and the DLC layers 19A and 19B, and compressive residual stress is induced in the second intermediate layers 26A and 26B and the DLC layers 19A and 19B which are brittle in strength. Can be made. As a result, in the case of Example 6, the DLC layers 19A and 19B were not damaged such as peeling until the number of repetitions of starting and stopping of the rotating machine was 500 cycles, and the second intermediate layers 26A and 26B In Example 7, in which a gradient composition layer was formed at the boundary between the third intermediate layers 31A and 31B to further reduce thermal stress, no damage due to peeling or the like was observed in the DLC layers 19A and 19B even after 1000 cycles. .

  According to the present embodiment, in addition to the same effects as the effects (1) to (7) of the first and second embodiments, the following effect (8) is achieved.

  (8) W, Mo, Ti third intermediate layers 31A, 31B having a smaller thermal expansion coefficient than the second intermediate layers 26A, 26B between the first intermediate layers 17A, 17B and the second intermediate layers 26A, 26B. Is provided to induce compressive residual stress in the second intermediate layers 26A, 26B and DLC layers 19A, 19B, which are brittle in strength, in the coating process of the third intermediate layers 31A, 31B and DLC layers 19A, 19B. As a result, the repetitive cycle characteristics associated with the start / stop of the rotating machine can be greatly improved.

[D] Fourth embodiment (see FIGS. 1 and 2)
In the fourth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The bearing 35 of the fourth embodiment is different from the bearing 10 of the first embodiment in that the hydrogen content of the DLC layers 36A and 36B is set to 10 to 30 at%. The hydrogen content in the DLC layers 36A and 36B is adjusted by changing the hydrogen composition ratio of the atmospheric gas introduced into the chamber when the DLC layers 36A and 36B are formed by sputtering.

  Next, a sliding test using the bearing 35 of the present embodiment will be described.

  In this test, the metal layers 16A and 16B of Cu-Cr alloy are sprayed on the inner side surfaces 14A and 14B of the bearing bases 12A and 12B made of structural steel, and the surfaces of the metal layers 16A and 16B are sprayed. A Cr layer as the first intermediate layers 17A and 17B and a W layer as the second intermediate layers 18A and 18B are sequentially formed by sputtering, and the DLC layers 36A and 36B are sputtered on the surfaces of the second intermediate layers 18A and 18B. The film was formed by the method. Bearing bearings 12A and 12B coated with such a coating were fastened with bolts 13 to obtain a bearing 35.

  In this bearing 35, the DLC layers 36A and 36B having a hydrogen content of 10 at% were designated as Example 8, 20 at% as Example 9, and 30 at% as Example 10. The DLC layers 36A and 36B having a hydrogen content of 5 at% were used as Comparative Example 4, and the one with 40 at% was used as Comparative Example 5.

  A shaft 23 simulating the rotor 11 was inserted between the pair of bearings 35, and a sliding test was performed by rotating the shaft 23 in lubricating oil. In this test, as described above, a load is applied to the central portion of the shaft 23 between the pair of bearings 35 to apply a surface pressure simulating an actual machine to the sliding surfaces 24A and 24B of the DLC layers 36A and 36B. The surface pressure applied to the sliding surfaces 24A and 24B was instantaneously changed to 1/2 times and 1.5 times the predetermined surface pressure.

The test results are shown in Table 4. In Comparative Example 4 in which the hydrogen content was too low, the DLC layers 36A and 36B were hard and brittle, so that cracks and partial omissions occurred after 100 cycles of the start / stop cycle of the rotating machine. On the contrary, in Comparative Example 3 in which the hydrogen content was too high, the DLC layers 36A and 36B were soft and thus worn or peeled off. On the other hand, in Examples 8 to 10 in which the hydrogen content is in the range of 10 to 30 at%, the DLC layers 36A and 36B were not damaged even when the number of repeated cycles was 500, and in particular, Examples 9 and 10 Thus, it can be seen that the DLC layers 36A and 36B are not damaged even after 1000 cycles.

  Therefore, according to the present embodiment, in addition to the same effects (1) to (5) as in the first embodiment, the following effect (9) is achieved.

  (9) By using the DLC layers 36A and 36B having a hydrogen content of at 10 to 30%, the wear resistance, toughness and ductility of the DLC layers 36A and 36B can be optimized. That is, the lower the hydrogen content, the higher the hardness and the wear resistance of the DLC layer, but the toughness and ductility are reduced and become brittle and easily broken. In addition, the DLC layer has higher ductility and toughness as the hydrogen content increases, but the hardness decreases and the wear resistance decreases. Therefore, by setting the hydrogen content to 10 to 30 at%, it is possible to achieve both wear resistance, toughness, and ductility of the DLC layers 36A and 36B.

[E] Fifth embodiment (FIG. 7)
FIG. 7 is a cross-sectional view showing a bearing to which the fifth embodiment of the bearing structure for a rotating machine according to the present invention is applied. In the fifth embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is simplified or omitted.

  The bearing 40 of the present embodiment is different from the bearing 10 of the first embodiment in that the inner side surfaces 14A and 14B of the bearing base metals 12A and 12B divided into two in the circumferential direction of the rotor 11 are arranged on the rotor 11 side. Are formed in a segment structure in which a plurality of segments 41 are formed in the circumferential direction. The metal layer 16, the first intermediate layer 17, the second intermediate layer 18, and the DLC layer 19 are formed on the inner surface 42 of each segment 41. Are sequentially laminated to form the sliding member 15, and the bearing bases 12 A and 12 B are fastened by the bolts 13.

  Each segment 41 is formed in a region sandwiched between the grooves 43 by forming a plurality of grooves 43 extending in the axial direction of the bearing 40 on the inner side surfaces 14A and 14B of the bearing bases 12A and 12B. The inner side surface 42 of the segment 41 is substantially synonymous with the inner side surfaces 14A and 14B. Similarly, the sliding member 15, the metal layer 16, the first intermediate layer 17, the second intermediate layer 18, the DLC layer 19, and the sliding surface 24 are respectively the sliding members 15A and 15B and the metal layer of the first embodiment. 16A and 16B, the first intermediate layers 17A and 17B, the second intermediate layers 18A and 18B, the DLC layers 19A and 19B, and the sliding surfaces 24A and 24B.

  Therefore, according to this embodiment, in addition to the same effects (1) to (5) as in the first embodiment, the following effect (10) is achieved.

  (10) A plurality of segments 41 are formed on the inner side surfaces 14A and 14B of the bearing bases 12A and 12B, and the metal layer 16, the first intermediate layer 17, the second intermediate layer 18, and the DLC layer are formed on each segment 41. Since 19 is sequentially laminated to form the sliding member 15, the sliding member 15 on the inner surface 42 of each segment 41 is separated from each other in the circumferential direction of the rotor 11. For this reason, it is possible to reduce the thermal strain caused by the thermal expansion generated in the sliding member 15 with the start / stop of the rotating machine, and to reduce the concentration of the thermal strain. As a result, the thermal stress acting on the DLC layer 19 can be reduced, and the lifetime and high reliability can be realized.

[F] Sixth embodiment (FIG. 8)
FIG. 8 is a cross-sectional view showing a bearing to which the sixth embodiment of the bearing structure for a rotating machine according to the present invention is applied. In the sixth embodiment, the same parts as those in the first and fifth embodiments are denoted by the same reference numerals, and the description will be simplified or omitted.

  The difference between the bearing 45 of the present embodiment and the bearing 10 of the first embodiment is that the inner surfaces 14A and 14B of the bearing base metals 12A and 12B divided into two in the circumferential direction of the rotor 11 have Fe, A plurality of pad bases 46 made of Cu alloy or Al alloy are point-supported using a pivot 47, and the metal layer 16, the first intermediate layer 17, and the second intermediate layer 18 are formed on the inner surface 48 of each pad base 46. The DLC layer 19 is sequentially laminated to form the sliding member 15, and the bearing bases 12 A and 12 B are fastened by the bolts 13.

  Therefore, according to this embodiment, in addition to the effects (1) to (5) of the first embodiment, the following effects (11) and (12) are obtained.

  (11) The metal layer 16, the first intermediate layer 17, the second intermediate layer 18, and the DLC layer 19 are sequentially formed on each of the plurality of pad base metals 46 point-supported on the inner side surfaces 14A and 14B of the bearing base metals 12A and 12B. Since the sliding members 15 are formed by being laminated, the sliding members 15 are separated from each other. For this reason, it is possible to reduce the thermal strain caused by the thermal expansion generated in the sliding member 15 with the start / stop of the rotating machine, and to reduce the concentration of the thermal strain. This tendency is that when the thickness of the pad base metal 46 is thin or the pad base metal 46 is made of Cu alloy or Al alloy having high thermal conductivity, the cooling performance is improved and the temperature rise of the DLC layer 19 is increased. Since it is suppressed, it becomes remarkable. Therefore, as a result of these, the thermal stress acting on the DLC layer 19 can be reduced, and its life extension and high reliability can be realized.

  (12) The pad base metal 46 on which the metal layer 16, the first intermediate layer 17, the second intermediate layer 18, and the DLC layer 19 are stacked is a small component compared to the bearing base metals 12A and 12B. The apparatus for thermally spraying, the apparatus for depositing the first intermediate layer 17, the second intermediate layer 18, and the DLC layer 19 by the sputtering method can be reduced in size, and the cost can be reduced.

Sectional drawing which shows the bearing to which 1st Embodiment in the bearing structure of the rotary machine which concerns on this invention was applied. Sectional drawing which shows typically the structure of the sliding member in the bearing of FIG. The III section expanded sectional view of FIG. Sectional drawing corresponding to FIG. 2 which shows typically the structure of a sliding member in the bearing to which 2nd Embodiment in the bearing structure of the rotary machine which concerns on this invention was applied. The V section expanded sectional view of FIG. Sectional drawing corresponding to FIG. 2 which shows typically the structure of a sliding member in the bearing to which 3rd Embodiment in the bearing structure of the rotary machine which concerns on this invention was applied. Sectional drawing which shows the bearing to which 5th Embodiment in the bearing structure of the rotary machine which concerns on this invention was applied. Sectional drawing which shows the bearing to which 6th Embodiment in the bearing structure of the rotary machine which concerns on this invention was applied. Sectional drawing which shows the conventional bearing. Sectional drawing which shows the other conventional bearing.

Explanation of symbols

10 Bearing 11 Rotor (Rotor)
12A, 12B Bearing base metal 13 Bolt 15, 15A, 15B Sliding member 16, 16A, 16B Metal layer 17, 17A, 17B First intermediate layer 18, 18A, 18B Second intermediate layer 19, 19A, 19B DLC layer 20 20A , 20B Intermediate layer 22A, 22B Curved surface 25 Bearing 26A, 26B Second intermediate layer 27A, 27B Gradient composition layer 30 Bearing 31A, 31B Third intermediate layer 35 Bearing 36A, 36B DLC layer 40 Bearing 41 Segment 42 Inner side surface 45 Bearing 46 Pad base metal 47 Pivot 48 Inside surface

Claims (10)

A bearing structure for a rotating machine that supports the rotor of the rotating machine,
A bearing base made of Fe-based metal;
A metal layer, an intermediate layer, and a diamond-like carbon layer are sequentially laminated on the bearing pedestal,
The metal layer is made of Cu, Al, or an alloy mainly containing at least one of these,
The intermediate layer has a first intermediate layer on the metal layer side and a second intermediate layer on the diamond-like carbon layer side,
A bearing structure for a rotating machine, wherein the first intermediate layer is composed mainly of Cr. The bearing structure for a rotating machine according to claim 1, wherein the second intermediate layer is composed mainly of at least one of W, Mo, and Ti. 2. The bearing structure for a rotating machine according to claim 1, wherein the second intermediate layer is made of a ceramic mainly containing at least one of TiC, TiN, TiCN, and SiC. 4. The bearing structure for a rotating machine according to claim 3, wherein the ceramic of the second intermediate layer has a continuous structure with respect to the first intermediate layer. A gradient composition layer in which a composition ratio of Cr of the first intermediate layer and ceramic of the second intermediate layer gradually changes is formed between the first intermediate layer and the second intermediate layer. The bearing structure for a rotating machine according to claim 3. The third intermediate layer mainly comprising at least one of W, Mo, and Ti is formed between the first intermediate layer and the second intermediate layer mainly containing ceramics. 4. A bearing structure for a rotating machine according to 3. The bearing structure for a rotating machine according to claim 1, wherein the diamond-like carbon layer has a hydrogen content of 10 to 30 at%. The base material is divided in the circumferential direction of the rotor, and when the divided base materials are bolted, the base materials are in contact with each other, and a metal layer laminated on each base material, 2. The bearing structure for a rotating machine according to claim 1, wherein the intermediate layer and the diamond-like carbon layer are configured so as not to contact each other. The base material is divided in the circumferential direction of the rotor, the inner surface side of each of the divided substantially semi-cylindrical base materials is divided into a plurality of segments, and a metal layer is formed on the inner surface of each segment. 2. The bearing structure for a rotating machine according to claim 1, wherein an intermediate layer and a diamond-like carbon layer are sequentially laminated, and each of the divided base members is bolted. The base material is divided in the circumferential direction of the rotor, and a plurality of pad bases made of Fe, Cu alloy or Al alloy are point-supported on the inner surface of each of the divided substantially semi-cylindrical base materials, The metal layer, the intermediate layer, and the diamond-like carbon layer are sequentially laminated on the inner side surface of each pad base metal, and each of the divided base members is bolted and configured. Rotating machine bearing structure.

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