JPH071033B2 - Straight-flow turbine runner blade support device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a runner blade support device for a straight flow type water turbine.

[Conventional technology]

The straight-flow turbine is a horizontal-axis turbine that is applied to the point of low head and large flow with a head of about 25m or less.
FIG. 6 is a schematic vertical sectional view of a straight flow type water turbine, and FIG. 6 is an internal detailed view of a runner blade supporting device of the straight flow type water turbine of FIG. In FIG. 5 or FIG. 6, the runner boss 4 has a blade shaft 5 for each of the plurality of runner blades 3.
Are movably supported via a link mechanism 6, and hydraulically drive a servo motor to operate the link mechanism 6.

A rotor 2a is provided on the outer circumference of the runner blade 3 via a rotor retaining ring 9.
And has a stator 2b facing the rotor 2a. The water turbine shaft 7 is supported by bearings 8 at the front and rear of the runner blade 3, and the head side of the water turbine shaft 7 is covered by the valve 1. Water flows in the direction of the arrow to rotate the runner blade 3 and The weight is applied to the bearing 8 via the runner blade 3, the runner boss 4, and the water wheel shaft 7. Since these blade shafts are rotated, there is a slight radial gap between them.

In the case of a tubular turbine, even if this gap exists, each part inside the runner boss is constantly pressed to the outer peripheral side due to the centrifugal force that acts on the blade during rotation of the runner, so the runner blade There is no rattling. On the other hand, in the case of a straight flow type water turbine, the weight of the rotor 2a is applied to the runner blades 3, and this load is often larger than the centrifugal force of the runner blades. Therefore, every time the runner blade makes one revolution, the runner blade shaft repeatedly moves in and out of the gap of the runner boss fitting portion, which may cause wear or damage of the water turbine shaft or the runner boss fitting portion.

[Problems to be solved by the invention]

In order to eliminate such a gap in the fitting part, a cotter-shaped pin 10 has been provided in the center of the conventional turbine shaft, and the runner blade shaft end is pressed from the inside via the collar 11 and the runner blade is constantly pressed against the thrust bearing surface. I was configured to be. The pin is urged by a spring 12 in a direction parallel to the turbine shaft, which pushes the pin so that the runner vanes are pushed radially through the collar 11 with respect to the turbine shaft. However, the runner blade or the thrust collar surface on the runner boss side and the pin itself generally have a processing error, and when the pin is formed into a conical shape, the pin and the collar come into contact with each other only at a certain point on the center of the water turbine shaft.

An object of the present invention is to keep the thrust collar and the pin in full contact by being pushed by the spring even if there is a processing error between the thrust collar and the pin.

[Means for solving problems]

The present invention provides a tapered pin that is movably arranged along the turbine axis and has a center line that is inclined with respect to the turbine axis, and that has the same number of cylindrical surfaces as the runner blades, and the turbine axis side of each of the blade shafts. A curved surface that is attached to the end and has a center line that faces each cylindrical surface of the pin end and inclines at the same angle as the cylindrical surface of the pin with respect to the water turbine axis and that has the same radius of curvature as the cylindrical surface of the pin. And a spring fixed to the runner boss so as to press the pin.

[Action]

According to the present invention, the tapered pin having the same number of cylindrical surfaces as the blade shaft and the curved surface having the same radius of curvature as the cylindrical surface of the pin attached to the water turbine shaft center side end of each blade shaft are pressed by the spring. And they make full contact with each other.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a pin of a runner blade support device for a straight flow type water turbine according to an embodiment of the present invention. FIG. 1 (a) is an external view of a pin end portion, and FIG. 1 (b) is FIG. 1 (a). FIG. 1 (c) is a partial view of the VV cross section of FIG. 1 (a). In FIG. 1, the end of the pin 10 has three cylindrical surfaces, which is the same number as the runner blade, as shown in FIG. 1 (a), and tapers toward the tip. The -U cross section has three identical cylindrical surfaces as shown in Fig. 1 (b). However, as shown in FIG. 1 (b), the VV cross section perpendicular to the surface of the cylindrical surface has the center of the circular arc of the cylindrical surface on the surface of the cylindrical surface, that is, the center of the pin of the straight flow type water turbine. It is out of alignment. A collar 12 having a curved surface that comes into contact with the cylindrical surface of the pin 10 is provided at the end of each blade shaft facing the pin 10 on the water turbine shaft center side.

FIG. 2 is an explanatory view of a cylinder forming the cylindrical surface of the pin end,
FIG. 2 (a) is an explanatory view of the cylinder A, and FIG. 2 (b) is an explanatory view taken in the direction of the arrow W in FIG. 2 (a). In FIG. 2, the axis of the pin 10 is the X-axis, the center line of the cylinder A that intersects the X-axis and the P-point is K _A, and the plane passing through K _A and the X-axis is the A plane, and the same diameter as the cylinder A. Of the cylinder B-C so that the center line K _B · K _C intersects the X axis at the point P and has an inclination angle θ, and the plane passing through K _B and the X axis is the plane B and the plane passing through K _C and the X axis is As the C surface, the B surface,
Cylinder so that C surface is 120 ° to A surface respectively
Set A, B, C.

FIG. 3 is an explanatory diagram showing the relationship between the center lines of the cylinders A, B and C forming the cylindrical surface of the pin end and the A surface, B surface and C surface. The center lines K _A , K _B , K _C is the P point on the X axis and θ axis and θ, respectively.
A plane that intersects at the corner of and intersects with K _A and the X axis,
The B plane passing through K _B and the X axis and the C plane passing through K _C and the X axis are 12 each other.
0 ° apart.

FIG. 4 is an explanatory view showing a cross section of the cylindrical surface of the pin end portion.
Indicates an intersection of the center lines K _A , K _B , K _C of the cylinders A, B, C and the X axis, and a cross section S passing through a point Q on the X axis and perpendicular to the center lines K _A , K _B , K _{C. When the} cylinders A, B, and C are cut by _A , S _B , and S _C , the arc that is the line of intersection of the cross section S _A and the cylinder A is R _A and the cross section S _B
Intersection line at which arc _{R B} between the cylindrical B, section _S and _C and an arc _{R C} is a line of intersection between the cylinder C, and the intersection of the cross-section _{S A} and the center line _{K A} R _KA Tosureba arc _{R A} radius R around the point RK _a is
Draw an arc of R, and R _B and R _C likewise draw an arc of radius R.

The cylindrical surface of the end portion of the pin 10 configured as described above is pushed in the horizontal direction by the spring, and the entire facing surface of the collar 12 at the end of the runner blade shaft is brought into contact with the cylindrical surface.

〔The invention's effect〕

According to the present invention, the center line between the cylindrical surface of the end of the pin, which is arranged so as to be movable along the turbine shaft center, and the curved surface of the collar, which is attached to the end of the blade shaft on the turbine shaft center side, has a center line. Since they have the same inclination with respect to the center and have the same radius of curvature, they are entirely pressed against each other at a certain position by a spring and the blade axes do not rattle.

[Brief description of drawings]

FIG. 1 shows a pin of a runner blade support device for a straight flow type water turbine according to an embodiment of the present invention. FIG. 1 (a) is an external view of a pin end portion, and FIG. 1 (b) is FIG. 1 (a). 2 is a U-U cross-sectional view, FIG. 1 (c) is a partial view of the V-V cross-section of FIG. 1 (a), and FIG. 2 is an explanatory view of a cylinder forming the cylindrical surface of the pin end portion. (A) is an explanatory view of the cylinder A, and FIG. 2 (b) is a second view.
FIG. 3A is an explanatory view showing the relationship between the center lines of the cylinders A, B and C forming the cylindrical surface of the pin end and the A surface, B surface and C surface, 4 is an explanatory view showing a cross section of the cylindrical surface of the pin end portion, FIG. 5 is a schematic vertical sectional view of a straight flow type water turbine, and FIG. 6 is an inside of a runner blade supporting device of the straight flow type water turbine of FIG. FIG. 3: Runner blade, 4: Runner boss, 5: Blade axis, 7: Water wheel axis, 1
0: Pin, 11: Color, 12: Spring, A, B, C cylinder, K _A , K _B ,
K _C : center line, R _A , R _B , R _C : arc.

Claims (1)

[Claims] 1. A plurality of runner blades having a blade shaft movably supported by a runner boss, a rotor mounted on the outer periphery of the runner blade via a rotor retaining ring, and a stator facing the rotor. In a straight-flow turbine, a tapered pin that is movably arranged along the axis of the turbine and has a center line that is inclined with respect to the axis of the turbine and that has the same number of cylindrical surfaces as the runner blade, and a turbine of each of the blade axes. It has a center line that is attached to the end on the axial center side and faces each cylindrical surface of the end of the pin and inclines at the same angle as the cylindrical surface of the pin with respect to the water turbine axis, and has the same radius of curvature as the cylindrical surface of the pin. A runner impeller supporting device for a straight flow type water turbine, comprising: a collar having a curved surface and a spring fixed to a runner boss so as to press the pin.