JPH078801Y2 - Ceramic turbine rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a ceramic turbine rotor that constitutes a turbine, a turbocharger, or the like.

(Problems to be solved by conventional techniques and devices) Nowadays, in order to reduce weight and improve running performance of automobiles to reduce fuel consumption, ceramics of internal combustion engines are being actively used, and turbine rotors of turbochargers are also being used. Practical trial production of ceramics is in progress. However, when foreign matter (for example, unburned carbon particles, metal particles, debris, etc.) is mixed in the exhaust gas of the turbine, especially when the size of the foreign matter is large with respect to the clearance between the turbine rotor and the turbine scroll. However, due to the nature of ceramics, there is a problem that the edge of the turbine blade is easily damaged by the inclusion of foreign matter. Therefore, a chamfered rounded edge of the turbine blade has been devised (Actual development 60-26204, 61-94201). It was found that the pressure side of the blade was easily damaged.

(Means and Actions for Solving Problems) The present invention has been made to solve the above problems, and forms slopes or roundness on the positive pressure side and the negative pressure side of the turbine shroud side edge of the turbine blade. Provided is a turbine rotor which is chamfered, has a radius of curvature of a positive pressure chamfer of 0.3 to 0.6 mm, and has a larger value for the positive pressure chamfer than for the negative pressure chamfer. Damage due to foreign matter on the edge of the turbine blade occurs when foreign matter caught from the negative pressure side of the turbine blade escapes to the positive pressure side, so it can be prevented by chamfering the edge on the positive pressure side, but the chamfering is not so much. The smaller the effect, the smaller the effect. However, if the chamfer is too large on the negative pressure side, foreign matter is likely to be caught, and since the turbine blade is thin, chipping and damage are likely to occur due to the impact when the foreign matter collides. Therefore, chamfering is performed on the positive pressure side more than on the negative pressure side.

(Example) FIG. 1 is an axial cross-sectional view of a turbine rotor and a turbine shroud. 1 is a turbine rotor, 2 is a turbine turbine blade of a turbine rotor, 4 is a turbine shroud, and 3 is a shroud side edge of the turbine blade. The shroud side edge portion is chamfered, and FIG. 2 is a partial perspective view of the turbine rotor 1 of the radial turbine, and FIG. 3 is a perspective view of the turbine blade of the axial flow turbine. Show. FIG. 4 shows the AA ′ of the turbine blade 2 in FIGS. 2 and 3.
A cut sectional view is shown. In the turbine blade 2 in these figures, 2-1 indicates the positive pressure side and 2-2 indicates the negative pressure side. Figure 4 (a)
Is an embodiment in which a chamfer is formed, and in the figure, the corner portion between the suction side 2-2 of the turbine blade 2 and the edge portion 3 has a large chamfer as described above, so that foreign matter is caught. Since the turbine blade 2 is thin, it is liable to chip and break due to the impact of foreign matter collision.
~ 0.3 mm is preferred. On the positive pressure side, if the chamfer is small, the effect is small, so 0.3 or more is desirable. Since the thickness of the tip of the turbine blade is about 1 mm, it is not preferable to increase the chamfer too much. Therefore, the chamfer on the positive pressure side is preferably 0.3 to 0.6 mm. The chamfer angle θ is generally 45 °, but 60 to 20
If it is °, the same effect can be obtained. FIG. 4B shows another embodiment in which chamfering with a roundness, that is, a radius (R), is shown.
~ 0.3 mm is preferable, and the radius (R) on the positive pressure side may be 0.3 mm or more.

Therefore, in a radial turbine, the outer diameter is 60 mm and the thickness is 1.2 m.
0.6 mm on the pressure side of the shroud side edge of the turbine blade 2 of m,
For the example in which the negative pressure side was chamfered to form a slope of 0.1 mm and the comparative example in which the positive pressure side and the negative pressure side were chamfered to form a slope of 0.1 mm, the clearance with the turbine scroll was set to 0.7 mm and 120,000. φ0.8m when rotated at rpm
As a result of throwing m foreign matter into the exhaust manifold, in the comparative example, the shroud side positive pressure side of the turbine blade was chipped and damaged, but the example was not damaged.

(Effect of the Invention) As described above, the positive pressure side and negative pressure side of the turbine shroud side edge of the ceramic turbine blade of the turbine rotor are chamfered, and the radius of curvature of the positive pressure side chamfer is 0.3 to 0.6 mm, and its value is By making the chamfer on the positive pressure side larger than the chamfer on the negative pressure side, it is possible to prevent chipping and damage due to foreign matter in the turbine blade, and it is possible to provide a long-life rotor.

[Brief description of drawings]

1 is an axial sectional view of a turbine rotor and a shroud, FIG. 2 is a partial perspective view of a turbine rotor of a radial turbine, FIG. 3 is a perspective view of turbine blades of an axial turbine, and FIG. ) Is a cross-sectional view of an embodiment of chamfering which forms a slope in the AA ′ cutting cross section shown in FIGS. 2 and 3, and FIG.
FIG. 2B is a cross-sectional view of an embodiment of chamfering with a rounded shape on the AA ′ cut step surface shown in FIGS. 2 and 3. 1: turbine rotor, 2: turbine blade, 2-1: positive pressure side of turbine blade, 2-2: negative pressure side of turbine blade, 3: shroud side edge,
4: Turbine shroud.

Claims (1)

[Scope of utility model registration request] 1. A ceramic turbine rotor for a turbocharger of an internal combustion engine, wherein a positive pressure side and a negative pressure side of a turbine shroud side edge portion of a turbine blade of the turbine rotor are chamfered so that a positive pressure chamfer has a radius of curvature. A ceramic turbine rotor having a diameter of 0.3 to 0.6 mm and a radius of curvature of a negative pressure chamfer of 0.1 to 0.2 mm.