JPH0710965B2 - Coating material for gap adjusting film layer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating material for a gap adjusting film layer,
More specifically, the present invention relates to a coating material used for a coating layer for allowing a movable member and a fixed member that move relatively close to each other to bring these gaps closer to 0 during operation.

[Prior Art] As a movable member and a fixed member that move close to each other and relatively move, an automobile turbocharger shown in FIG. 6 will be described as an example. This turbocharger has a turbo rotor 100 and an impeller 200 as movable members, and has a turbo housing 101 and a compressor housing 201 as fixed members. In such a turbocharger, the turbo rotor 100 rotates by the exhaust energy of the engine (not shown) to rotate the shaft 300, and the rotation of the shaft 300 causes the impeller 200 to rotate and supercharge air to the engine.

By the way, these turbo rotor 100 and turbo housing 1
It is known that the efficiency of the turbocharger is improved by making the gap C100 with 01 and the gap C200 between the impeller 200 and the compressor housing 201 as small as possible. However, if these gaps C100 and C200 are reduced, the shaft
Due to a slight eccentricity in manufacturing 300, the turbo rotor 100 may come into contact with or collide with the turbo housing 101 during operation, or the impeller 200 may be compressed by the compressor housing 201.
The turbo rotor 100 and the impeller 200 may be damaged due to contact with or collision with. Therefore, in the conventional turbocharger, there is a limit to the reduction of the clearances C100 and C200, and the efficiency is insufficient.

In a turbocharger or a jet engine having a movable member and a fixed member that move relatively close to each other in this way, the gap between the movable member and the fixed member can be reduced as much as possible, and the efficiency can be improved. It has been desired to develop a technique capable of preventing damage to the movable member. In recent years, a coating layer is formed on a portion of the fixed member in the vicinity of the movable member by thermal spraying, and the coating layer is ground by relative movement of the movable member to prevent damage to the movable member and A gap adjusting film layer that makes the gap between the movable member and the movable member close to 0 is being put to practical use.

As the conventional thermal spray material for the gap adjusting coating layer, a mixed powder of heat-resistant polyester plastic (trade name Econol) and Al disclosed in JP-B-52-4494,
A thermal spray material composed of a soft metal and a resin or graphite having lubricity such as Ni-graphite powder and Al-graphite powder disclosed in Japanese Patent Publication No. 60-18746 is known. These thermal spray materials have already been implemented in aircraft jet engine compressors, shroud covers, and the like.

[Problems to be Solved by the Invention] However, the conventional thermal spray material for the gap adjusting coating layer has been developed mainly for jet engines for aircraft, and therefore has the following problems.

That is, since these thermal spray materials form a machinable coating layer with a relatively hard movable member such as a Ti alloy having a hardness of about Hv200, an Al alloy having a hardness of about Hv120 or a hardness of Hv70. When the coating layer is cut with a movable member that is softer than a Ti alloy such as a Mg alloy, the movable member is easily damaged and a large torque is required in the initial stage of the cutting.

Further, since these thermal spray materials form a coating layer by thermal spraying for small-quantity production products and custom-made products, the material cost and the thermal spraying equipment cost increase, and the coating efficiency at the time of thermal spraying is poor, so that the coating film layer is not formed. The cost will be high.

The present invention has been made in view of the above-mentioned conventional problems, and provides a coating material for a gap adjusting coating capable of forming a coating layer that can be machined even with a relatively soft movable member with low torque at low cost. With the goal.

[Means for Solving the Problem] The coating material for a gap adjusting coating layer of the present invention comprises 20 to 80% by volume of a hollow balloon made of a ceramic material, and a matrix remainder containing a resin for binding the hollow balloon. It is a feature.

The hollow balloon is made of a ceramic material. As this hollow balloon, silica balloon, alumina balloon, magnesia balloon, glass balloon, zirconia balloon, carbon balloon, pearlite, etc. can be adopted.

Hollow balloon is 20 in the coating material for the gap adjustment coating layer
Occupy ~ 80% by volume. If it is less than 20% by volume, the hollow balloon is hard to be cut, so that the machinability of the coating layer is not sufficiently improved, and if it exceeds 80% by volume, the hollow balloon is hard to be bonded and the coating layer lacks strength.

The particle diameter of the hollow balloon is preferably 3 to 20 μm. If the thickness is less than 3 μm, the hollow balloons are firmly bonded in the matrix, so that the machinability of the coating layer is not sufficiently improved.
If it exceeds, the opponent's aggression becomes large and the movable member as the opponent material is easily damaged.

The shell thickness of the hollow balloon is preferably 0.5 to 5 μm. 0.5μ
When it is less than m, the strength of the hollow balloon is insufficient, so that the strength of the coating layer is insufficient, and when it exceeds 5 μm, the aggressiveness against the opponent is increased and the movable member is easily damaged.

The matrix occupies the balance in the coating material for the gap adjusting coating layer. The matrix includes a resin that binds the hollow balloon. The resin has a hardness lower than that of the hollow balloon, and is selected according to heat resistance, bonding strength, type of hollow balloon, and the like. For example, siloxane resins such as polymethylphenylsiloxane, polyphenylene sulfide (PPS), polyether sulfone (PES),
Resins such as ethylene tetrafluoride ethylene copolymer (PETFE) can be adopted.

The matrix may contain a reinforcing material such as glass fiber in an amount of less than 30% by volume based on the resin. If it exceeds 30% by volume, the reinforcing material tends to have a bad influence on machinability and opponent aggressiveness.

The coating material for the gap adjusting coating layer in the present invention,
The invention is applicable to a turbocharger for automobiles, a jet engine for aircraft, and the like, which have a movable member and a fixed member that move close to each other and relatively move. The relative movement between the movable member and the fixed member may be rotational movement or direct movement.

A coating layer is formed by coating the portion of the fixed member adjacent to the movable member with the coating material for a gap adjusting coating layer of the present invention. The coating can be performed by a method such as spraying or dipping using an organic solvent that dissolves the matrix. Such coating may be performed directly on the portion of the fixed member that is close to the movable member, but in order to improve the adhesion between the coating layer and the fixed member, surface treatment is performed on that portion of the fixed member by a method such as shot blasting. It is preferably performed after the application or / and after coating the resin as the intermediate layer on that portion of the fixing member. After coating, the organic solvent of the resin may be removed by natural evaporation to form a film layer, but if the organic solvent is forcibly removed by heating at a predetermined temperature, a porous film layer is likely to be formed. Machinability is further improved.

[Function] In the coating layer formed of the coating material for a gap adjusting coating layer of the present invention, hollow balloons that are destroyed by a weak force exist in the matrix, and the destroyed hollow balloons are considered to be separated while scraping the matrix. To be Therefore, it is considered that the coating material of the present invention can form a coating layer that can be machined with a low torque even with a relatively soft movable member. Further, in the present invention, since the coating is adopted, the coating layer can be formed at a low cost as compared with the thermal spraying.
By using a resin having excellent heat resistance, a coating layer that can be used even at high temperatures can be formed.

[Examples] Hereinafter, the present invention will be described by Tests 1 to 4 using Examples and Comparative Examples.

<Test 1> Here, a coating layer obtained from the coating material of the present invention was compared with a coating layer obtained from a conventional thermal spray material.

(Example 1) First, a commercially available silica balloon (Sumitomo 3M, trade name: Glass Bubble) was prepared. This silica balloon was obtained by a general heat-foaming method including steps of raw material, mixing (slurrying), drying, crushing, sieving (particle size adjustment), heat-foaming and collecting, and an average particle size of 50 ~ 100μ
m, and an average shell thickness of 1 to 3 μm. In addition, commercially available glass fiber was prepared. This glass fiber is 100wt% SiO
Consisting of ₂ , average diameter 0.5 to 5 μm, average length 10 to 100 μm
belongs to. Further, polymethylphenylsiloxane having the chemical formula shown below was prepared.

50% by volume of these silica balloons, 15% by volume of glass fibers,
A slurry was prepared by mixing 30 to 35% by volume of polymethylphenylsiloxane with a thinner as a solvent.

On the other hand, a flat plate (30 × 50 × 5 mm) made of S45C was prepared, and the surface thereof was shot blasted with a calcined alumina powder having a particle size of 500 to 1500 μm, and then coated with polymethylphenylsiloxane as an intermediate layer of about 10 μm.

The surface of the flat plate having the intermediate layer was coated with the slurry to a thickness of 0.5 μm using a spray gun. Then, this was put in a heating furnace and heated in the atmosphere at 200 ° C. for 1 hr to remove the thinner. Thus, the test piece of Example 1 was obtained.

(Comparative Example 1) The above flat plate was shot-blasted in the same manner as in Example 1, and a plasma spray gun (METCO7MB) was used on the surface of the plate to spray current: 400 A, working gas: argon 180 psi, hydrogen 2.
60 wt% Al-Si + 40 wt% heat resistant polyester (METCO601) was sprayed under the condition of 0 psi. Thus, the test piece of Comparative Example 1 was obtained.

Comparative Example 2 54 wt% Al-Si + 46 wt% graphite (METCO313NS) was sprayed in the same manner as in Comparative Example 2 above. Thus, a test piece of Comparative Example 2 was obtained.

Comparative Example 3 75 wt% Ni + 25 wt% graphite (METCO307NS) was sprayed in the same manner as in Comparative Example 2 above. Thus, the test piece of Comparative Example 3 was obtained.

(Evaluation) The test piece of Example 1 has an intermediate layer on a flat plate and a coating layer on the intermediate layer, as shown in the cross section of FIG. 2 in a micrograph. On the other hand, the test pieces of Comparative Examples 1 to 3 have a coating layer formed by thermal spraying on a flat plate. The machinability and opponent attack of the coating layer in each of the test pieces of Example 1 and Comparative Examples 1 to 3 were evaluated. Evaluation,
As shown in FIG. 3, Mg alloy (JISMC2-T ₆₎ made of the rotating disk 4 formed with external teeth 3 relative to the coating layer 2 on the specimen 1
While continuously pressing while pressing from the direction of the arrow in the figure, check the film cutting depth (mm) as an index of machinability, and measure the amount of wear (mg) of the turntable as an index of opponent attack. Went by. The pressing force is 50 g / mm ² , the rotation speed is 1
The test time is 000 rpm and the test time is 60 seconds. The results are shown in Fig. 1.

As shown in FIG. 1, the test piece of Example 1 has a small amount of wear of the rotating disk and a large depth of film cut, despite the fact that the mating material is a soft Mg alloy. It can be seen that it has a coating layer that is hard to wear and has excellent machinability. on the other hand,
It can be seen that the test pieces of Comparative Examples 1 to 3 have a large amount of wear on the rotating disk and a small depth of work for cutting the coating, so that the mating material easily wears and has a coating layer with poor machinability.

Moreover, the average hardness at a plurality of positions was measured as a wide-area hardness of the coating layer of each test piece of Example 1 and Comparative Examples 1 to 3 using a micro Vickers hardness meter with a load of 1 kg. As a result, the test piece of Example 1 is Hv7 to 10, the test piece of Comparative Example 1 is Hv15, the test piece of Comparative Example 2 is Hv21, the test piece of Comparative Example 3 is Hv25, and the test piece of Example 1 is It had the lowest Hv value.

The coating layers in the test pieces of Comparative Examples 1 to 3 are formed by thermal spraying of soft metal and resin or graphite, and cannot be said to be so hard. But,
The coating layer of the test piece of Example 1 has a lower apparent hardness including the matrix than the coating layers of Comparative Examples 1 to 3. This is a hollow balloon that is easily broken in the coating layer of Example 1 even though it is made of a ceramic material such as silica, contains polymethylphenylsiloxane of about Hv3 to 6 and forcibly removes the thinner by heating. Therefore, it is considered that this is because it is a porous film layer that is soft enough to be scraped by a nail. in this way,
Since the coating layer of the test piece of Example 1 is softer than the coating layer of the test piece of Comparative Examples 1 to 3,
It is considered that the coating layer of the test piece of No. 2 had the most excellent machinability and opponent attacking property.

Since the test piece of Example 1 uses polymethylphenyl siloxane as the resin, it decomposes.
If it is about 0 ° C. or lower, heat resistance can be expected.

<Test Piece> Here, the optimum blending amount of the hollow balloon with respect to the matrix was measured.

The blending amount of the silica balloon as a hollow balloon is 0
A test piece was obtained in the same manner as in Example 1 of <Test 1> except that the content was changed at 90% by volume, and each test piece was evaluated in the same manner as in <Test 1>.

As a result, when the content was less than 20% by volume, the matrix content was large and the mating material was slippery due to the low friction coefficient, and the coating cut depth decreased. On the other hand, when it exceeds 80% by volume, the hollow balloon cannot be supported due to the small amount of matrix, and the coating layer peels off, and the evaluation was stopped.

From this result, it was confirmed that the optimum content of the hollow balloon in the coating material of the present invention was 20 to 80% by volume.

<Test 3> Here, the optimum particle diameter of the hollow balloon was measured.

Examples 2 to 9 were performed in the same manner as in Example 1 of <Test 1> except that the particle diameter of the silica balloon was changed variously as shown in Table 1.
The test piece of 1 was obtained, and each test piece was evaluated in the same manner as in <Test 1>. Results are shown in FIG.

From Table 1 and FIG. 4, it can be seen that when the particle diameter of the hollow balloon is extremely small as in Example 2, the depth of cut of the coating becomes small. This is probably because the hollow balloon having a small particle size is easily fixed in the matrix and the hollow balloon is difficult to be separated due to the movement of the mating material. On the contrary, when the particle diameter of the hollow balloon is extremely large as in the case of Example 9, it is found that the opponent attacking property is increased. It is exposed on the surface of the coating layer as the particle size of the hollow balloon increases. This is probably because the hollow balloon has a large surface area and behaves like a lump of silica with a hardness of Hv500 to 700, and the mating material is easily worn.

From this result, it is understood that the coating material of the present invention exhibits substantially the same machinability and opponent attacking property in the range of the particle diameter of the hollow balloon of 3 to 200 μm.

<Test 4> Here, the adhesion of the coating layer was measured.

The evaluation was performed by using the test pieces of Example 1 and Comparative Examples 1 to 3 of <Test 1> and measuring the magnitude of the load causing the peeling of the coating layer by a shear test.

As a result, the test pieces of Comparative Examples 1 to 3 caused peeling of the coating layer at 1 to ² kgf / mm ² , whereas the test piece of Example 1 was 2 to 2.
At 3 kgf / mm ² , peeling occurred in the coating layer. Further, in the test piece obtained without providing the intermediate layer in Example 1, peeling occurred at 1 to ² kgf / mm ² , and the adhesion was similar to that of the test pieces of Comparative Examples 1 to 3.

From this result, it is understood that the coating material of the present invention can form a film layer having good adhesion by providing the intermediate layer.

If the coating material for a gap adjusting coating of the present invention is applied to the turbocharger, for example, as shown in FIG.
A film layer 400 is formed by coating on a portion P adjacent to. The coating layer 400 is abraded by the rotation of the turbo rotor 100 and prevents damage to the turbo rotor 100, while improving the efficiency by bringing the gap between the turbo housing 101 and the turbo rotor 100 close to zero. .

[Effects of the Invention] As described in detail above, since the coating material for a gap adjusting coating layer of the present invention has a hollow balloon in the matrix, it has a low coating layer that can be machined even with a relatively soft movable member at a low torque. It can be formed at a cost.

That is, the coating layer formed of the coating material for the gap adjusting coating layer of the present invention is an Al alloy having a hardness of about Hv120 or a hardness of Hv120.
Even when a soft movable member such as a v70 Mg alloy is used, the movable member will not be damaged and large torque will not be required even in the initial stage of machining. .

Further, the coating material for the gap adjusting film layer of the present invention,
The coating layer can be formed with good coating efficiency without burdening the material cost and the equipment cost, and can be applied to mass-produced products and distribution-produced products.

[Brief description of drawings]

1 to 3 relate to Test 1, FIG. 1 is a graph for comparing the characteristics of the test pieces of Examples and Comparative Examples, and FIG. 2 is a 200 × micrograph showing the particle structure of the test pieces of Example, Third
The figure is a schematic side view showing a test method for each test piece. Fourth
The figure is a graph comparing the characteristics of the test pieces of the example according to Test 3. FIG. 5 is a sectional view of a main part of a turbocharger having a coating layer. FIG. 6 is a vertical sectional view of a conventional turbocharger.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hitoshi Hemi 3210-103 Notsuda-cho, Machida-shi, Tokyo (72) Inventor Minoru Sonoda 79-14, Eiga Nishidaine, Toyoake-shi, Aichi

Claims (1)

[Claims] 1. A hollow balloon 20 comprising a ceramic material.
A coating material for a gap adjusting film layer, which comprises 80% by volume and the rest of a matrix containing a resin for binding the hollow balloon.