JPH05195942A - Rotor support bearing for straight-flow type water turbine - Google Patents

Abstract

PURPOSE:To generate no gap in a sliding part by eliminating compressive force applied to a member forming a rotor support bearing during the rotation of the runner of a straight flow type water turbine. CONSTITUTION:A flexible block 13 made of non-metallic material is provided between a rotor holding ring 8 and recessed side member 9b forming the rotor support bearing 10 of a straight flow type water turbine. The radial displacement of the rotor 2a generated in association with the rotation of the water turbine is absorbed by this flexible block 13. The flexible, block 13 reduces the wear and damage of the rotor support bearing 10 considerably without the generation of metal fatigue in the water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor support bearing for supporting a rotor in a straight flow type water turbine on a runner blade.

[0002]

2. Description of the Related Art FIG. 2 is a vertical sectional view of a straight flow type water turbine. The straight flow type turbine is an axial flow turbine with a horizontal axis applied to a point with a low head with a head of about 25 m or less and a large flow rate. In the straight flow type turbine, a plurality of runner blades 4 are attached to a runner boss 5, and a turbine shaft 6 integrated with the runner boss 5 is supported by a turbine bearing 7. The rotor 2 a is attached to the outer diameter side of the runner blade 4 via a rotor holding ring 8. The generator 3 is the rotor 2
a and a stator 2b facing the rotor 2a. In FIG. 2, the runner boss 5 movably supports respective blade axes of the plurality of runner blades 4 via a link mechanism, and hydraulically drives a servo motor to operate the link mechanism.

FIG. 3 is a longitudinal sectional view of a rotor support bearing of a conventional straight flow type water turbine. In FIG. 3, a rotor support bearing 10 is composed of a convex side member 9a attached to the outer periphery of the runner blade 4 and a concave side member 9b held inside the rotor holding ring 8, and the rotor support bearing 10 is a bearing. Case 11
It is housed in. The rotor 2a is held by the rotor holding ring 8, and the stator 2b is arranged so as to face the rotor 2a. The water turbine shaft 6 is supported by the water turbine bearings 7 in front of and behind the runner blade 4, and the head side of the water turbine shaft 6 is covered with the valve 1. Water flows in the direction of the arrow to rotate the runner blade 4. The weight of the rotor 2a is applied to the rotor support bearing 10 via the runner blade 4, the runner boss 5, and the water wheel shaft 6. Even when the angle of the blades 4 changes due to the operation of the link mechanism, the rotary holding ring 8 is supported perpendicularly to the water wheel shaft 6 via the rotor support bearing 10. Since the rotor retaining ring 8 is displaced to the outer diameter side by the centrifugal force, the rotor retaining ring 8 and the convex side member 9a of the rotor support bearing 10 are in contact with all the operating states of the water turbine (at the time of stop, rated operation, and load shedding). The concave side member 9b is pressed toward the inner diameter side by the compression spring 12 so that no gap is formed between the concave side member 9b and the concave side member 9b in the radial direction.

[0004]

In the case of a movable vane type straight flow type water turbine, the angle of the runner blade 4 with respect to the rotor retaining ring 8 changes, so that a spherical convex side is formed on the outer periphery of the runner blade 4. The member 9a is fixed by bolts, and the concave member 9b is fixed on the rotor holding ring 8 side. The total weight of the rotor 2a and the rotor holding ring 8 and the repulsive force by the compression spring 12 are applied to the 3 to 5 runner blades 4, and the load is often larger than the centrifugal force of the runner blades 4 themselves. Furthermore, the distribution of the load acting on the bearing changes significantly depending on the circumferential position of the bearing due to the rotation of the runner.
Severe rebound load acts on the convex side member 9a, the concave side member 9b, and the compression spring 12. Since the convex side member 9a, the concave side member 9b, and the compression spring 12 are in water, the compression spring is likely to be damaged by metal fatigue due to a severe bending load.

The present invention provides a rotor support bearing in which a compressive force applied to a member constituting the rotor support bearing is lost while the runner of a straight flow type turbine is rotated and a gap is not formed in a sliding portion. The purpose is to provide.

[0006]

[Means for Solving the Problems] A plurality of runner blades whose blade shafts are movably supported by a runner boss and a rotor support bearing composed of a convex side member and a concave side member are attached to the outer circumference of the runner blade. In a straight flow type water turbine including a rotor retaining ring, a rotor retained by the rotor retaining ring, and a stator facing the rotor, between the concave member and the rotor retaining ring. The above-mentioned object is achieved by providing a flexible block made of a non-metal in the above and absorbing the radial displacement of the rotor due to the rotation of the water turbine by the flexible block.

The use of annular rubber as the flexible block is suitable for preventing metal fatigue in water.

[0008]

According to the present invention, since the flexible block made of non-metal is provided between the rotor retaining ring and the concave side member of the rotor support bearing, the rotor is rotated by the centrifugal force caused by the rotation of the rotor. The repeated load applied to the support bearing can be absorbed by the flexible block. Moreover, since the flexible block is made of non-metal, even if the rotor is immersed in water, metal fatigue in water does not occur.

[0009]

1 is a vertical sectional view of a rotor support bearing of a straight flow type water turbine according to an embodiment of the present invention. 1, the same parts as those in FIG. 3 are designated by the same reference numerals. In FIG. 1, the blade shafts of a plurality of runner blades 4 are movably supported by a runner boss (not shown) via a link mechanism. The rotor 2 a attached to the rotor holding ring 8 and the stator 2 b facing the rotor 2 constitute the generator 3. A rotor support bearing 10 is composed of a convex side member 9a attached to the outer circumference of the runner blade 4 and a concave side member 9b held inside the rotor holding ring 8, and the rotor support bearing 10 is provided in the bearing case 11. It is housed. A flexible block 13 made of an annular rubber is inserted in a small space between the rotor support bearing 10 and the rotor holding ring 8 on the outer peripheral side thereof. Due to the compressive force of the flexible block 13, no gap is created between the convex side member 9a and the concave side member 9b. The flexible block 13 is held by the block retainer 14.
The compression force of the flexible block 13 is adjusted by the driving position of the taper key 15 when the rotor support bearing 10 is assembled.

[0010]

According to the present invention, since the flexible block presses the rotor support bearing toward the inner diameter side against the severe bending load applied to the rotor support bearing during operation of the water turbine, the convex side member and the concave side There is no gap between the members. Further, since the flexible block does not cause metal fatigue in water, wear damage of the bearing can be significantly reduced and the life of the rotor support bearing can be extended.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a rotor support bearing of a straight flow type water turbine according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a straight flow type water turbine.

FIG. 3 is a vertical cross-sectional view of a rotor support bearing of a conventional straight flow turbine.

[Explanation of symbols]

 2a rotor 2b stator 3 generator 4 runner blade 8 rotor retaining ring 9a convex side member 9b concave side member 10 rotor support device 11 bearing case 13 flexible block 14 block retainer 15 taper key

Claims (2)

[Claims] 1. A rotor retaining ring mounted on the outer circumference of the runner blade via a rotor support bearing composed of a plurality of runner blades whose blade shafts are movably supported by a runner boss, and a convex side member and a concave side member. And a rotor held by the rotor holding ring, and a straight flow type water turbine including a stator facing the rotor, in a non-metal between the concave member and the rotor holding ring. A rotor supporting bearing for a straight flow type water turbine, characterized in that the flexible block is provided and the radial displacement of the rotor due to the rotation of the water turbine is absorbed by the flexible block. 2. The rotor support bearing for a straight-flow water turbine according to claim 1, wherein the flexible block is made of an annular rubber.