JPH0627761Y2 - Coupling shaft structure of ceramic turbine rotor and metal shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a coupling shaft structure of a ceramic turbine rotor and a metal compressor impeller rotating shaft.

(Prior Art) A conventional turbine rotor of this type is used for connecting a shaft portion 32 of a ceramic turbine rotor 31 and a metal rotating shaft 33 to each other as shown in FIG. 3 or FIG. The shaft portion 32 is fixed to a hole 34 formed on the rotary shaft 33 side of the metal sleeve 35 by a method such as press fitting, shrink fitting, or brazing. In actual use, bearings 36 and 37 are provided on the outer circumference of the metal sleeve 35 to support the turbine rotor 31. As the bearings 36 and 37, floating bearings, ball bearing bearings and the like are used.

However, in the above-described turbine rotor coupling shaft structure, when the turbine rotor is rotated by exhaust gas or when the rotation is suddenly stopped, heat flows in axially from the turbine rotor portion exposed to high temperature. The shank sometimes became hot. As a result, the lubricating oil existing between the bearing and the shaft portion deteriorates due to heat, and the bearing or the shaft portion wears, which impedes normal rotation of the turbine rotor.

(Problems to be solved by the invention) In order to avoid such a problem, an example in which a heat insulating layer is provided inside the journal shaft is disclosed in Japanese Utility Model Publication No. 59-67539 and Japanese Utility Model Publication No. 59-67539.
No. 60-114201.

However, in the technique disclosed in Japanese Utility Model Laid-Open No. 59-67539, the journal shaft is formed into a cylindrical shape to provide an air layer for the purpose of the heat insulating layer effect, but the manufacturing cost is high due to the insertion of the reinforcing member and the manufacturing process is complicated. There was a problem that became.

Further, in the technology disclosed in Japanese Utility Model Laid-Open No. 60-114201,
An air layer is provided in the journal shaft of the part that abuts the bearing part, but the air layer is provided by scraping the ceramic side, the ceramic shaft diameter becomes smaller, the thermal insulation coefficient becomes smaller, and the air layer becomes the bearing part. There is a problem that the ceramic shaft is easily broken at the end of the air layer when a bending load acts on the journal shaft, and the ceramic shaft is easily broken.

An object of the present invention is to solve the above-mentioned problems and to provide a highly reliable ceramic turbine rotor in which breakage of a ceramic shaft due to provision of a heat insulating layer is prevented and wear of a bearing portion is reliably prevented. To do.

(Means for Solving the Problems) The coupling shaft structure of the ceramic turbine rotor and the metal shaft of the present invention is provided with a ceramic shaft portion integrally with the ceramic turbine rotor, and this shaft portion and the metal rotary shaft of the compressor impeller. A metal sleeve formed integrally with the metal shaft portion, the bearing metal on the metal sleeve side of the coupling boundary surface between the ceramic shaft portion and the metal sleeve surrounding the ceramic shaft portion is A heat insulating layer is provided in a portion corresponding to the abutting portion, and both ends of the heat insulating layer in the axial direction are in contact with the ceramic shaft portion of the ceramic turbine rotor within the same shaft diameter.

(Operation) In the above-mentioned configuration, since the ceramic is fixed within both ends of the heat insulating layer corresponding to the bearing metal on the turbine side within the same shaft diameter, the span l is short even when a bending load acts on the rotor. The bending moment acting on the portion A of FIG. 2 is smaller than that of the conventional example having the heat insulating layer, and the ceramic shaft is a ceramic turbine rotor which is hard to be broken.
By providing the heat insulating layer directly below the journal shaft with which the bearing metal abuts, heat conduction to the bearing is reliably prevented, and the manufacturing can be performed at low cost. Further, when the shaft portion is short, a similar effect can be achieved by providing the heat insulating layer only on the portion corresponding to the bearing on the side closer to the turbine rotor.

(Embodiment) FIG. 1 is a diagram showing an embodiment of the coupling shaft structure of the present invention. In this embodiment, the ceramic shaft portion is long, and therefore two heat insulating layers are provided. The ceramic turbine rotor 1 has an integrally formed shaft portion 2, and the shaft portion 2 is press-fitted into a metal sleeve 4 of a metal rotating shaft 3, shrink-fitted, bonded with an adhesive, or bonded with a brazing material. Join in one way. Floating bearings 5-1 for supporting the turbine rotor 1 are provided at both ends of the metal sleeve 4.
Provide 5-2. A space is provided on the metal sleeve 4 side of the boundary surface between the bearing 2 and the metal sleeve 4 corresponding to the floating bearings 5-1 and 5-2 to form a heat insulating layer 6-1, 6-2, and the bearing metal on the turbine side is formed. The both ends in the axial direction of the heat-insulating layer with which the are in contact with each other are fixed within the same shaft diameter. A seal ring groove 7 and an oil slinger 8 are provided at the end of the metal sleeve 4.

FIG. 2 is a diagram showing another embodiment of the coupling shaft structure of the present invention. In this embodiment, the ceramic shaft portion is short, so that the heat insulating layer is provided only at one location on the turbine rotor side. The shaft portion 12 formed integrally with the ceramic turbine rotor 11 is composed of a large diameter portion 13 on the turbine rotor 11 side and a small diameter portion 14 at the other end. The metal sleeve 17 of the metal rotary shaft 15 is composed of a large diameter sleeve 18 and a small diameter sleeve 19 having diameters corresponding to the large diameter portion 13 and the small diameter portion 14, respectively. The shaft portion 12 is joined into the metal sleeve 17 by any of the methods of press fitting, shrink fitting, joining with an adhesive, and joining with a brazing material. Ball bearing bearings 20-1 and 20-2 for supporting the turbine rotor 11 are provided at both ends of the small-diameter sleeve 19 of the metal sleeve 17. Also the turbine rotor 1
A space is provided on the thin sleeve 19 side of the boundary surface between the thin portion 14 of the shaft portion 12 and the thin sleeve 19 of the metal sleeve 17 corresponding to the ball bearing bearing 20-1 on the first side, and a heat insulating layer 21 is formed. Then
Both ends of the heat insulating layer in the axial direction are fixed within the same shaft diameter. Also,
A seal ring groove 22 and an oil slinger 23 are provided on the outer circumference of the large-diameter sleeve 18 of the metal sleeve 17. Further, at the boundary between the large-diameter portion 13 and the small-diameter portion 14, a void portion 24 is provided between the large-diameter portion 13 and the metal sleeve 17 surrounding the outer circumference of each of these portions to avoid excessive stress concentration on that portion.

The present invention is not limited to the above-described embodiments, but various modifications and changes can be made. For example, in the above-described embodiments, the air layer formed by the voids is used as the heat insulating layer, but the voids may be filled with a heat insulating material or the like as needed.

(Effect of the Invention) As is clear from the above description, in the coupling shaft structure of the ceramic turbine rotor and the metal shaft of the present invention, the ceramic shaft portion and the metal corresponding to the portion where the bearing of the ceramic rotor abuts. By providing a heat insulating layer on the metal sleeve side of the boundary surface of the sleeve, and fixing both axial ends of the heat insulating layer corresponding to the bearing metal on the turbine side within the same shaft diameter, when a bending force acts on the rotor, ceramic The shaft becomes a ceramic turbine rotor that does not easily break, and further blocks the heat flow from the turbine rotor into the bearings.
It was possible to prevent deterioration of the lubricating oil between the bearing and the rotating shaft and to reliably prevent wear of the bearing portion, and as a result, it was possible to significantly improve the reliability of the ceramic turbine rotor.

[Brief description of drawings]

1 and 2 are diagrams showing an embodiment of the connecting shaft structure of the present invention, and FIGS. 3 and 4 are diagrams showing an embodiment of the connecting shaft structure of a conventional turbine rotor. is there. 1,11 …… Turbine rotor, 2,12 …… Shaft 3,15 …… Metal rotating shaft, 4,17 …… Metal sleeve 5-1,5-2 …… Floating bearing 6-1,6-2 , 21 …… Insulation layer, 7,22 …… Seal ring groove 8,23 …… Oil slinger 13 …… Large diameter part, 14 …… Narrow diameter part 18 …… Large diameter sleeve, 19 …… Thin diameter sleeve 20- 1,20-2 …… Bearing bearing

Claims (3)

[Scope of utility model registration request] 1. A structure in which a ceramic shaft portion is provided integrally with a ceramic turbine rotor, and the shaft portion and a metal rotating shaft portion of a compressor impeller are connected by a metal sleeve integrally formed with the metal shaft portion. A heat insulating layer is provided in a portion corresponding to a portion of a coupling boundary surface between the ceramic shaft portion and the metal sleeve surrounding the ceramic shaft portion, the bearing metal on the metal sleeve side is in contact with,
A combined shaft structure in which both axial ends of the heat insulating layer are in contact with the ceramic shaft portion of the ceramic turbine rotor within the same shaft diameter. 2. The coupling shaft structure according to claim 1, wherein the heat insulating layer is provided only in a portion corresponding to the bearing metal on the ceramic turbine rotor side, and is registered as a utility model. 3. A utility model registration claim according to claim 1, wherein the ceramic shaft portion and the metal sleeve are connected by press fitting, shrink fitting, bonding by an adhesive, or bonding by brazing. Bond axis structure.