JPH03156103A - Relative displacement device - Google Patents

Abstract

PURPOSE:To improve machined property even under a high temperature by providing a coating layer which is flame-coated at a portion near a moving element for a fixing member, contains 10vol% or more ceria and has the face machined and created by the moving element. CONSTITUTION:A coat layer 85 is provided which is flame-coated at a portion P near a turbo rotor 82 for a turbo housing 81, contains 10vol% or more ceria and has the face machined and created by the turbo rotor 82. As a result, the machined property can be made excellent even under a high temperature. The turbo rotor 82 is therefore hard to be damaged and even when it is used under a high temperature for a long time, the coating layer 85 is prevented from separation, falling or corrosion, so that a gap between the turbo rotor 82 and the turbo housing 81 can be brought rear to zero.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a relative movement device, such as a turbocharger or a gas turbine, which has a movable member and a fixed member that move relatively to each other in close proximity at high temperatures. Specifically, the present invention relates to a relative displacement device that can bring the gap between a fixed member and a movable member close to zero during operation.

[Prior Art] A conventional relative displacement device will be described by taking, for example, an automobile turbocharger shown in FIG. 12 as an example. This turbocharger has a turbo rotor 100 and an impeller 200 as movable members, and a turbo housing 101 and a compressor housing 201 as fixed members. Such a turbocharger has a turbo rotor 1
00 is rotated by the exhaust energy of an engine (not shown) to rotate a shaft 300, and the rotation of the shaft 300 rotates an impeller 200, thereby supercharging air to the engine.

In this way, the turbo rotor 100 and the turbo housing 10
1 and impeller 200 and compressor housing 20
1 move close to each other under high temperature and move relative to each other during operation of the turbocharger.

By the way, it is known that the efficiency of the turbocharger can be improved by making the gap C100 between the turbo rotor 100 and the turbo housing 101 and the gap C200 between the impeller 200 and the compressor housing 201 as small as possible. However, these gaps C100, C200
If it is made small, the turbo rotor 100 may come into contact with or collide with the turbo housing 101 during operation, or the impeller 200 may come into contact with or collide with the compressor housing 201, due to slight eccentricity caused during the manufacturing of the shaft 300. There was a possibility that the turbo rotor 100 and the impeller 200 would be damaged.

Therefore, in the conventional turbocharger, the gap C10 between the turbo rotor 100 and the turbo housing 101 is
0 is approximately 0.6 to 0.8 mm, and the gap C200 between the inhaler 200 and the compressor housing 201 is approximately 0.3 to 0.8 mm.
It needed to be 0.5 mm, which was insufficient in terms of efficiency.

Relative transfer like this! For the 7I device, it has been desired to develop a technique that can improve efficiency by reducing the gap between the movable member and the fixed member as much as possible, and prevent damage to the movable member. Conventionally, as such a technique, a technique has been disclosed in which a coating layer containing a mixture of soft metal and resin or graphite is formed on the compressor housing side by thermal spraying. In this conventional technology, the formed film layer is easily scraped off when the impeller comes into contact with the compressor housing due to eccentricity of the shaft, etc., so the gap between the impeller and the compressor housing after being scraped off can be made close to O. can. Note that this will not damage the impeller. Other techniques for making the gap between the movable member and the fixed member close to O by utilizing the machinability of such a film layer are disclosed in Japanese Patent Application Laid-Open No. 18085/1985 and US Patent No.

There are 4405284. These disclose techniques for coating Ni-graphite and NiCrFeAl-BN.

Further, US Patent No. 4,269,903 discloses a technique for coating a porous stabilized zirconia layer with a porosity of 20 to 33% as an invention related to a ceramic seal. This technique is basically the same as the above invention, and also with this technique, the gap between the movable member and the fixed member in the relative displacement device can be made close to O due to the machinability of the porous stabilized zirconia layer.

[Problems to be Solved by the Invention] However, even if the relative displacement device is manufactured using the above-mentioned conventional technology, there are various drawbacks.

That is, the technology disclosed in US Pat. No. 4,269,903 uses zirconia, which is resistant to thermal shock, as a coating layer in consideration of high-temperature use, and makes the zirconia porous to ensure machinability of the coating layer. However, in this technique only zirconia was sprayed.
In a coating layer with a porosity of ~33%, zirconia is HV
Since it has a high hardness of 100O or more, it has the disadvantage that the movable member that is the counterpart of the coating layer is easily abraded by the coating layer. In addition, if the coating layer is made of zirconia with a porosity of 33% or more, for example 40%, in order to further improve the machinability of the coating layer, the thermal shock resistance will decrease and the coating layer may peel or fall off. There is a disadvantage that it occurs.

Also, Japanese Patent Application Laid-Open No. 18085/1985, US Patent No.
In the technology of 4405284, since the coating layer is metal-based, it is impossible to withstand the high temperature of 1000°C, which is the highest temperature found in aircraft jet engines (gas turbine engines), for a long time, and it will eventually oxidize and corrode, so it cannot be repaired. The drawback is that you have to do it.

The present invention has been made in view of the above-mentioned difficulties in the conventional art.
The object of the present invention is to provide a relative movement device equipped with the following.

Although Japanese Patent Publication No. 50-690 is not a technology that utilizes the rigidity of the coating layer, it is an invention related to gas turbine engines in which the turbine casing is molded and sintered from a ceramic material that is softer than the turbine blades. Discloses a technology to prevent blade damage. However, this technique has the drawback that the bonding strength of the ceramic material is weak and durability is lacking.

Furthermore, Japanese Patent Application Laid-Open No. 62-1'68926 discloses coating the inner surface of the turbo housing or compressor housing with a composite material to optimize the gap between the turbo housing and the turbo rotor or the gap between the compressor housing and the impeller during operation. Discloses technology to do so. However, this does not disclose the material of the coating layer.

[Means for Solving the Problems] A relative movement device of the present invention is a relative movement device having a movable member and a fixed member that move relatively to each other in close proximity under high temperature, wherein the movable member of the fixed member The portion adjacent to the movable member is characterized by having a coating layer formed by thermal spraying, containing 10% by volume or more of ceria, and having a generated surface created by being cut by the movable member.

The relative displacement device according to the present invention is a turbocharger for an automobile or an aircraft, a gas turbine, or the like, and has a movable member and a fixed member that move relatively to each other in close proximity under high temperature. For example, if a turbocharger is a relative moving device, the impeller and turbo rotor correspond to movable parts.
A compressor housing and a turbo housing correspond to fixed members. If the gas turbine is a relative moving device, the turbine blades correspond to the movable member, and the turbine casing corresponds to the fixed member. Furthermore, the relative movement between the movable member and the fixed member may be rotational movement or linear movement.

A portion of the fixed member adjacent to the movable member is provided with a film layer. The film layer contains ceria (Ce02) as a cutting aid.
) Formed by thermal spraying with an abradable material containing 10% by volume or more of powder.

If the ceria content in the coating layer is less than 10% by volume, the machinability of the coating layer will not be improved sufficiently, but if the ceria volume content is high, the machinability will be improved. Among oxides, ceria is extremely suitable as an ablable material for gap adjustment in relative displacement devices, as shown in Table 1, which shows the Mohs hardness and coefficient of thermal expansion of major oxide powders. This is because it has a coefficient of thermal expansion close to that of metal, considering that it is soft compared to other materials and is sprayed onto parts that are used at high temperatures of 800 to 1000°C. However, among oxides, cao and sa
o, 5rot, tThe Mohs hardness shows a good value, but because it reacts with moisture in the atmosphere and produces hydroxide,
It is not preferable for the abradable material to contain this first surface. In addition, the particle size of the ceria powder is practically preferably 10 to 100 μm.

Examples of powders that can be included in the abradable material together with ceria include oxide powders such as alumina (Al2O2>, zirconia (ZrO2), and yttria (Y2O2)), hexagonal (hereinafter omitted) boron nitride (BN) powder, graphite powder, Mica powder can be used. BN powder, blyphite powder, and mica powder are used as machining aids that improve machinability. For example, when BN is mixed into ceria, the laminated structure of BN improves machinability. The particle size of these powders is 10 to 100% for oxide powders.
For μTW, BN powder, etc., 5 to 50 μm is practically preferable.

As the thermal spraying method, a plasma jet melting method or a gas spraying method can be adopted.

The film layer has a generated surface. Such a generated surface is created by being cut by a movable member during operation of the relative displacement device.

[Function] The relative displacement device of the present invention includes a film layer containing 10% by volume or more of ceria on a portion of the fixed member that is close to the movable member. In such a film layer, as schematically shown in FIG. 10, cutting aid particles 52 such as BN or graphite exist in a layered structure at the boundaries of oxide particles 51, and the oxide particles 5
Pores 53 also exist at the boundaries between the particles 1 and the cutting aid particles 52. In addition, the fixing member is indicated by the reference numeral 61 in the figure.

As schematically shown in FIG. 11, the present inventor has discovered that there are four types of mechanisms in which the film layer of the above structure is abraded by the movable member 62 that moves relative to the fixed member 61. I consider that there is.

■ Shear failure of the oxide particles 51 (a-1>■ Falling off of the oxide particles 51 with the boundaries of the pores 53 (a-2>) Falling off of the oxide particles 51 with the boundaries of the cutting aid particles 52 (a -3) ■ Shear failure of the cutting aid particles 52 (a-4> Among the above mechanisms, the oxide particles 51 fall off at the boundaries of the pores 53 (a-2>) It is thought that the oxide particles 51 are adhered with a weak adhesion force,
It is believed that moderate force is required. In addition, the oxide particles 51 fall off with the cutting aid particles 52 as a boundary (a-3)
The oxide particles 5 are reduced by the cutting aid particles 52 having low thermal properties.
1. Since it is thought that they are bonded with a weak bonding force, it is thought that a small force is sufficient. Therefore, the shear fracture of the oxide particles 51 (
a-1) and shear failure of the cutting aid particles 52 (a-4>
If other conditions are the same, the smaller the force required for these shear fractures @ (a-1, a-4), the easier it is to cut the skin #! This will be layer A. It is thought that the force required for shear fracture <a-1) of the oxide particles 51 is approximately proportional to the hardness of the oxide particles 51 themselves, so the soft oxide particles 5
1, it is thought that if ceria is included in the coating layer, the force required for cutting can be reduced.

Therefore, in the relative displacement device of the present invention, the movable member can cut the coating layer without requiring much force. Therefore, the coating layer is easily abraded to create a generated surface without damaging the movable member.

By creating this generated surface, the gap between the movable member and the fixed member is brought closer to O, thereby minimizing gas leakage and improving efficiency.

Furthermore, in the relative displacement device of the present invention, the porosity of the film layer is not increased, and the film layer is not formed of a metal-based material. Therefore, the coating layer does not peel off, fall off, or corrode at high temperatures.

[Example] Hereinafter, an example embodied in a turbocharger will be described together with a comparative example.

<Embodiment 1> As shown in a partial sectional view in FIG. 1, this turbocharger is basically the same as the conventional one (see FIG. 12), and includes a turbo housing 81 with an inner diameter of 55 mm,
The turbo rotor 82 is connected to a shaft 80. This turbocharger includes a coating layer 85 on a portion P of the turbo housing 81 that is close to the turbo rotor 82 . The steps for making this turbo housing are shown below.

(2) As shown in FIG. 2, in this turbocharger, the gap CO between the turbo housing 81 and the tarp roller 82 was approximately 0.8 mm before the coating layer 85 and the like were formed.

(2) A portion P of the turbo housing 81 adjacent to the turbo rotor 82 was subjected to shot blasting using calcined alumina powder having a particle size of 1200 to 1400 μm.

,■ As shown in Fig. 3, in order to improve adhesion to the shot-blasted portion P, N i CrA I (94 (8ON 120Cr
) -6A I) The alloy was plasma sprayed to a thickness tl of 0.08 to 0.1 mm to form an alloy layer 84.

(2) CeO2 powder (manufactured by Showa Denko) with a particle size of 10 to 74 μm was prepared and used as an abradable material.

(2) Approximately 1. Plasma sprayed with a thickness t2 of Omm,
A film layer 85 was formed.

■After forming the film layer 85, the gap C1 between the turbo housing 81 and the turbo rotor 82 is reduced to 0.05 by NC machining.
The film layer 85 was processed to have a thickness of mm. Note that the porosity of the formed film layer 85 was 23%.

In this way, the turbocharger of Example 1 was created.

<Example 2> This turbocharger uses C as an abradable material.
The turbocharger was the same as the turbocharger of Example 1, except that a mixture of eO2 powder 7 and Y203 powder 25% by volume was used. In addition, ZrO2 20Y203 powder (manufactured by Showa Denko) has a particle size of 1.
0-44 μm. The CeO2 powder was the same as in Example 1, and the porosity of the formed film layer was 21%.

<Example 3> This turbocharger uses C as an abradable material.
The turbocharger was the same as the turbocharger of Example 1, except that the turbocharger was composed of 3 eO2 powder, 30% Y203 powder, and 70% by volume of Y203 powder. Note that the ZrO2.20Y2 03 powder and CeO2 powder are the same as in Example 1, and the porosity of the formed film layer is 1.
It was 9%.

Comparative Example 11> This turbocharger uses Z as an abradable material.
The turbocharger was the same as that of Example 1 except that rO2.20Y203 powder was used. In addition, ZrO2
・20Y2 03 powder is the same as grain large flow side 1,
The porosity of the formed film layer was 30%.

Comparative Example 12> This turbocharger uses A as an abradable material.
The turbocharger was the same as that of Example 1 except that l2O3 powder was used. Note that the Al2O3 powder (Meteco 1 01 B>) had a particle size of 35 to 74 μm, and the porosity of the formed film layer was 28%.

Evaluation〉 Using the turbochargers of Examples 1, 2, and 3 and Comparative Examples 11 and 12, a 300-hour actual machine durability test was conducted to investigate abnormal noises, investigate the state of the film layer after operation, and examine the turbo rotor after operation. In addition to conducting a condition investigation, the weight loss (g) of the turbo rotor after operation was measured. Based on this, a comprehensive evaluation was given by marking "○" to those considered to be superior and "X" to those considered to be inferior. The results are shown in Table 2.

As shown in the results, in the turbochargers of Examples 1 and 2, even if the turbo rotor 82 contacts or collides with the film layer 85 during operation, the film layer 85
is easily cut by the turbo rotor 82, and the coating layer 8
Since the generation surface 851 was created on the surface of the engine 5, there were no abnormal noises, no abnormalities in the condition of the film layer, or in the condition of the turbo rotor. Further, the turbocharger of Example 3 had no particular problems other than a slight abnormal noise.

On the other hand, in the turbochargers of Comparative Examples 11 and 12, the coating layer had poor machinability, so a large noise was generated when the turbo rotor came into contact with the turbochargers during operation. In addition, in the state of the film layer after operation, in the turbocharger of Comparative Example 11, when the turbo rotor contacts the film layer, the film layer is peeled off rather than scraped, resulting in deformation of the rotor field after operation.
There was also a weight loss due to wear. Furthermore, Comparative Example 12
The turbocharger has a maximum turbo operating temperature of 950'
Because the thermal shock resistance of the film layer provided in C is poor,
1/3 of the coating layer peeled off, and the rotor blades were deformed and cracked, which is thought to be caused by the poor machinability of the coating layer and collisions between the peeled coatings, and the amount of wear was 1/2.
It was the biggest in 2Q.

Using the turbocharger of Example 1.2, when the evaluation of single unit performance was measured as overall efficiency (%) under the condition of rotor rotation speed of 100,000 rpm, it was 51% compared to the turbocharger without a film layer. In comparison, the one of Example 1 is 5
．． The efficiency was improved by 3%, and the efficiency of Example 2 was improved by 5.1%.

This is because, as shown in FIG. 4, the gap between the generating surface 851 and the turbo rotor 82 is almost zero, so that gas leakage can be minimized.

Therefore, Examples 1.2 with a film layer containing ceria.
The turbocharger No. 3 can prevent damage to the turbo rotor and improve efficiency.

[Test example] Next, the present invention will be explained using test examples.

(1) Test pieces of Examples 4 to 8 and Comparative Examples 13 to 20 were prepared using abradable materials whose compositions are shown in Table 3, and comparative tests were conducted on these abradable materials.

Each test piece is a flat plate made of 345C (30X30X5mm)
Each abradable material was obtained by plasma spraying to a thickness of 1.0 mm. In addition, BN powder (Shoden U
HP-EX) has a particle size of 35 to 45 μm, CeO2 powder, A
The l2O3 powder and ZrO2.20Y203 powder are the same as those described above.

The machinability of the film layer in each test piece of Examples 4 to B and Comparative Examples 13 to 20 was evaluated. In the evaluation, as shown in Fig. 5, a Φ10 Inconel ring 90 made of the same material as the turbo and rotor was placed on each test piece under the conditions of a surface load of 150Q/mm2, a rotation speed of ``loooorpm'', and a rotation time of 1 minute. This was done by rotating the ring 90 in the direction of the arrow in the figure.The depth at which the film layer of each test piece was scraped by the ring 90 was defined as the cutting depth (mm), and the aggressiveness of the specimen was expressed as the ring wear amount (mm). mci>.The results are shown in FIG.

From FIG. 6, the test pieces of Examples 4 to 8 containing ceria are different from the test pieces of Comparative Example 14 containing ZrO2.20Y203 with high porosity.
It can be seen that this test piece is easier to scrape and is more preferable than the test piece of Comparative Example 17, which is currently used in aircraft.

In addition, when comparing the test pieces of Comparative Examples 13.14 and 15.16, it can be seen that the machinability of the ZrO2.20Y203-based film layer is improved by the inclusion of BN. However, it can be seen that even these materials are highly aggressive and are still insufficient as abradable materials for adjusting gaps in relative displacement devices. On the other hand, it can be seen that the CeO2-based coating layers in the test pieces of Examples 4 to 8 exhibited small mating aggressiveness and excellent machinability even without mixing other machining aids such as BN.

(2) Vickers hardness (1-I
V) was measured. The results are shown in FIG.

From FIG. 7, the film layers of Examples 4 to 8 containing CeO2 are as follows:
It is determined that the coating layer is particularly soft and easily scraped compared to the coating layers of Comparative Examples 13 to 20. Further, by comparing Example 4 and Examples 5 and 6, it can be seen that machinability is further improved by including BN.

(3) When a coating layer was thermally sprayed with an abradable material containing CeO2, the coating layer had good machinability.
The optimum value of CeO2 was investigated from the viewpoint of machinability and thermal shock resistance.

Tests from machinability> CeO2 and ZrO2・20 as abradable materials
The proportion of CeO2 in the mixed powder with Y203 is O~1
Test pieces were prepared in the same manner as in the test (1) above, with various changes within the range of 0.00% by volume. Here, ZrO2.20Y203 and CeO2 are the same as above. Then, the cutting depth (mm) of the coating layer and the ring wear amount (
mq> was measured in the same manner as in the test (1) above. The results are shown in FIG.

As shown in Figure 8, Ce in the abradable material
The coating layer with more O2 has better machinability. When CeO2 was 10% by volume, the machinability deteriorated to the same extent as the test piece in Comparative Example 4 of the US patent (1) above (see Figure 6). If it is less than that, machinability is markedly deteriorated. Therefore, if you want to obtain a film layer with good machinability, it is necessary to
It turns out that eO2 is required.

Test based on thermal shock resistance> The thermal shock resistance of the film layer containing CeO2 was measured by a thermal cycle test. First, test pieces were prepared in substantially the same manner as in the test (1) above, with the ratio of CeO2 in the mixed powder with ZrO2.8Y203 or Al2O3 as an abradable material being varied in the range of O to 100% by volume. In addition, a test piece using the same abradable material as in Comparative Example 4.17 of (1) above was also prepared in the same manner.

In this test, before spraying each abradable material, 0.1 m of the alloy consisting of NiCr, A, and L was coated.
Plasma sprayed to a thickness of m. Here ZrO2・8Y20
3 (Shoden 90) has a particle size of 10 to 74 μm, Al2O3
and CeO2 are the same as above.

Then, as one cycle, each test piece was
They were heated to about 1000°C for 32 seconds with a burner, and then quenched by placing them in water. The cycle was repeated until part or all of the film layer peeled off or fell off, and thermal shock resistance was evaluated based on the number of cycles until peeling. Note that confirmation was performed every 50 cycles, and up to a maximum of 2000 cycles. The results are shown in Figure 9.

From Figure 9, the thermal shock resistance of Comparative Example 14.1
Although it is almost the same as Comparative Example 14.17, it can be seen that if CeO2 is 10% by volume or more, it is equivalent to or higher than Comparative Example 14.17. In addition, as the oxide powder, ZrO2.8
It can be seen that Y203 has better thermal shock resistance than Al2O3.

From the above machinability and thermal shock resistance tests,
As shown in FIGS. 8 and 9, it was confirmed that 10% by volume or more of CeO2 can form an effective film layer in terms of machinability and thermal shock resistance.

From the above tests (1), (2), and (3), it can be said that an abradable material containing 10% by volume or more of ceria powder is optimal as a thermal spray material for gap adjustment in a relative displacement device.

[Effects of the Invention] As detailed above, in the relative displacement device of the present invention, the portion of the fixed member adjacent to the movable member is formed by thermal spraying, contains 10% by volume or more of serifs, and is not cut by the movable member. Since it has a film layer with a generated surface created by the process, it has excellent machinability even at high temperatures. Therefore, in the relative displacement device of the present invention, the movable member is less likely to be damaged, and even when used for a long time at high temperatures, the film layer does not peel, fall off, or corrode, and the gap between the movable member and the fixed member is reduced. It has excellent efficiency and long life.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a turbocharger according to an embodiment. FIG. 2, FIG. 3, and FIG. 4 are partially enlarged sectional views of the turbocharger of the embodiment. FIG. 5 is a perspective view showing the test method for the test piece. FIG. 6, FIG. 7, FIG. 8, and FIG. 9 are characteristic diagrams comparing the characteristics of the example and the comparative example. FIGS. 10 and 11 are schematic sectional views showing the reason for the effect of the present invention. FIG. 12 is a sectional view of a conventional turbocharger. 82... Turbo rotor (movable member) 81... Turbo housing (fixed member) P... Adjacent part

Claims (1)

[Claims] (1) A relative movement device having a movable member and a fixed member that move relatively close to each other under high temperature, wherein a portion of the fixed member that is close to the movable member is formed by thermal spraying,
1. A relative displacement device comprising a film layer containing 10% by volume or more of ceria and having a created surface created by being cut by the movable member.