JPH0622082Y2 - Turbin rotating body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine rotating body such as a gas turbine or a turbocharger on which a high temperature gas fluid acts.

[Conventional technology]

In recent years, turbine rotors that are exposed to high-temperature gas fluids in various industrial machinery are limited in heat resistance by conventional rotor rotors made of heat-resistant and corrosion-resistant metal materials. Various ceramic turbine rotating bodies have been studied and proposed by applying ceramic bodies having excellent wear resistance and small specific gravity, especially sintered bodies such as zirconia, silicon nitride, sialon, and silicon carbide.

The turbine rotor incorporated in the industrial machine is made of a ceramic having a hub portion, a plurality of blades provided on an outer peripheral portion of the hub portion, and a protrusion portion integrally formed on an axial core portion of the bub portion. A rotating shaft made of carbon steel, tool steel, heat-resistant alloy steel, or the ceramic sintered body is joined to the rotating body by means such as shrink fitting or brazing, and is rotatably supported.

Since such a rotary rotor rotates at a high speed of several hundreds of thousands of revolutions per minute, even if there is a very slight imbalance in the mass around the rotational axis of the rotary rotor, very large vibration and bearing Uneven wear occurs, and as a result, not only vibration noise is generated and the life of the bearing is shortened, but
A large bending moment acts on the turbine rotor and the rotating shaft integrated with the turbine rotor, and the ceramic rotor comes into contact with the wall of the turbine chamber to damage the ceramic rotor itself, and also the entire device. It will cause a situation.

Therefore, a turbine rotating body that rotates at high speed requires highly accurate dynamic balance.

Generally, the correction of the dynamic balance of the turbine rotating body having the above-mentioned structure is performed by the measuring device after the centering finish processing of the joined body of the ceramic rotating body and the rotating shaft is completed. The direction and amount in which the mass is unbalanced are found, and based on this, as shown in FIG. 7, one end of the protruding portion 15 integrally formed on the small diameter side of the hub portion 14 of the ceramic rotating body 13 and the above-mentioned This is done by grinding and removing the back surface 16 of the hub portion 14, respectively.

[Problems to be solved by the invention]

However, when the back surface 16 of the hub portion 14 is rotated at a high speed, an extremely large stress is generated. When the back surface 16 is ground and removed to correct the dynamic balance as described above, the stress is concentrated on the ground and removed portion, and the rotation of the ceramic rotation is made. The body itself may be destroyed.

Therefore, by avoiding the grinding of the back surface 16, the blade end surface 17 of the ceramic rotating body 13 on the back surface 16 side is obliquely ground and removed from the blade root portion 18 to the blade tip portion 19, or the maximum outer diameter of the ceramic rotating body 13 is increased. The blade tip portion 19 of the portion 20 is ground and removed.

However, in such a dynamic balance correction method, as shown in FIG. 8, among the plurality of blades 21 provided on the outer peripheral portion of the hub portion 14, some outer peripheral portions of the blades 21 are ground and removed. As a result, the combustion gas flow is disturbed and the ceramic rotor 13 is easily broken from the back surface 16 of the hub portion 14 following the blade root portion 18 in the low speed rotation range, resulting in a reduction in the breaking rotation speed of the turbine rotor. Not desirable.

[Means for solving problems]

The present invention has been made in view of the above situation, and in a turbine rotating body in which a rotating shaft made of metal or the like is joined to a ceramic rotating body, it is surrounded by a hub between the blade end faces on the back side of the ceramic rotating body and a hub. The scalloped portion at the periphery of the opened opening has a curved surface or a tapered surface that has been ground away for correction of dynamic balance.

In the present invention, the dynamic balance can be achieved by grinding and removing the back surface of the hub portion of the ceramic rotating body, or by grinding and removing the back end surfaces of the plurality of blades of the ceramic rotating body and the outer peripheral tip of the blade. Since there is no portion where stress concentrates on the back surface of the hub portion because there is no correction of combustion gas flow because all of the blade outer peripheral tip portions have the same shape, It acts to increase the breaking speed to a higher speed.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 4 show an embodiment of a turbine rotating body according to the present invention, in which the back surface 8 of the hub portion 2 has a tapered shape, and FIGS. 5 and 6 show the back surface 8 respectively. Another embodiment having a straight shape and a stepped taper shape will be shown.

In these drawings, reference numeral 1 denotes a turbine rotating body, and the turbine rotating body 1 has a cone-shaped hub portion 2,
A plurality of blades 3 provided on the outer peripheral portion of the hub portion 2,
A ceramic rotating body 5 made of a silicon nitride sintered body having a protrusion 4 formed integrally with the shaft core of the hub 2 is attached to a protrusion 4 on the large diameter side of the hub 2 from heat-resistant alloy steel. The rotating shaft 6 is integrally joined by means such as shrink fitting or brazing.

After the centering finish processing of the turbine rotor 1 having the above-described structure is completed, the measuring machine finds out the direction and amount in which the mass around the rotation axis of the turbine rotor 1 is unbalanced, and based on this, As a balance correction point, a scallop portion 7 between the blade end faces 11 on the rear surface 8 side of the ceramic rotating body 5 and the peripheral edge of the opening 12 surrounded by the hub portion 2.
Is a tapered surface 9 that is chamfered to 1/2 or less of the thickness of the blade 3, or a curved surface 1 having a curvature of 1/2 or less of the thickness.
Grinding to 0, correcting the dynamic balance so that the unbalance amount is less than 0.02 gcm, and adjusting the exhaust gas temperature to 950
A high temperature, high speed rotation endurance test at ℃ was performed, and the results shown in Table 1 were obtained.

As a dynamic balance correction point, a turbine rotor in which the back surface of the hub portion and the tip of the outer peripheral edge of the blade were ground and removed was used as a comparative example, and the sample numbers in Table 1 are marked with *.

As is apparent from Table 1, a comparative example in which the back surface of the hub portion was ground as a dynamic balance correction point (sample numbers 1, 6,
No. 8, 10, 12, 14, 16) fractured from the ground portion of the back surface in the low speed rotation range, and the comparative example (sample Nos. 2 and 4) in which the outer peripheral tip of the blade was also ground fractured rotation The test result was obtained that the number was lower than that of the invention examples (sample numbers 3, 5, 7, 9, 11, 13, 15, 17) in which the scallop portion was ground.

[Effect of device]

As described above, according to the present invention, since the scallop portion is ground and removed so as to have a curved surface or a tapered surface to correct the dynamic balance, there is no fear that the ceramic rotating body is destroyed in the low speed rotation range, In addition, since the shape balance of the turbine rotor can be maintained well, it is possible to prevent contact between the ceramic rotor and the turbine chamber, as well as to improve the rotational stability during high-temperature and high-speed rotation. It is extremely effective in improving the rotational performance of the body.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a turbine rotor according to the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIGS. 3 and 4 are shown in FIG. 2B. FIG. 5 and FIG. 6 show another embodiment according to the present invention, FIG. 7 shows a conventional turbine rotor, and FIG. 8 shows a CC cross section of FIG. The figure is shown. 1 ... Turbine rotor 2 ... Hub part 3 ... Blade 4 ... Projection part 5 ... Ceramic rotor 6 ... Rotating shaft 7 ... Scallop part 8 ... Back surface 9 ... Tapered surface 10 ... Curved surface 11 ... Blade end face 12 ... Opening

Claims (1)

[Scope of utility model registration request] 1. A turbine rotating body comprising a hub portion and a ceramic rotating body having a plurality of blades provided on an outer peripheral portion of the hub portion, wherein a blade end surface on the back side of the ceramic rotating body and a hub. A turbine rotating body characterized in that a curved surface or a tapered surface for dynamic balance correction is formed on a scallop portion around an opening surrounded by a portion.