JPH0353441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stacked rotor used in axial flow machines such as axial flow compressors and axial flow turbines.

A typical example of a conventional stacked rotor of this kind is the first rotor.
As shown in the figure, a plurality of wheels 1 each having rotor blades 3 attached to their outer peripheral surfaces are stacked in the axial direction, and these wheels 1 are connected by a plurality of stacking bolts 2 having end pieces (not shown) at both ends. It is constructed by tightening and joining together. That is, as shown in FIG. 2, the wheel 1 has an arbitrary number of stacking bolt holes 4 provided at equal intervals in the circumferential direction of the joint surface 5, and a stacking bolt 2 is inserted into each of these bolt holes 4. When the wheels 1 are tightened by penetrating the wheels 1, the joint surfaces of the adjacent wheels 1 are brought into pressure contact with each other to generate a surface pressure and are joined together. The stacked rotor is assembled in this way, and after the balance is corrected, it is assembled into an axial flow machine.

In a stacked rotor with the above structure, the driving torque of the drive machine (not shown) is transferred from one end piece to the adjacent wheel, and from this wheel to the other wheel in turn due to the frictional force of each joint. communicated.

The wheel 1 is provided with a spigot 6 for positioning in the radial direction, but due to variations in the amount of tightening of the stacking bolts 2,
Due to slight differences in machining accuracy and roughness, a large centrifugal force load during high-speed rotation causes the joining surfaces, which do not cause relative slippage from a macroscopic perspective, to slip in the radial direction from a microscopic perspective. Therefore, even if static balance correction and low-speed dynamic balance correction are performed, once high-speed operation is performed, a large imbalance may occur.

When such unbalance occurs, the radial vibration of the stacked rotor increases, increasing the risk of contact between the rotor and stator and damage to the bearings, thereby interfering with plant operation. Since the shaft vibration is the physical phenomenon most closely related to serious failures in fluid machinery, it requires a great deal of effort and skill to correct the balance of the rotor in order to reduce the vibration.

In view of the above, the present invention aims to prevent an increase in unbalance due to high-speed rotation and to reduce vibration in the radial direction.By restraining the relative displacement of each wheel in the circumferential direction, the rotation of the rotor This prevents the relative position from changing between the front and back.

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 3 and 4, the rotor blade 3 is attached to the outer peripheral surface.
The wheels 1 equipped with
Stacking bolts 2 passing through bolt holes 4 are tightened to press the joint surfaces 5 of adjacent wheels 1 together. At least three (eight in the figure) grooves 6 are formed in the joint surface 5 in the radial direction and are equally spaced in the circumferential direction, and a key 7 is inserted into each of these grooves 6. There is.

In this embodiment, eight keys 7 are provided on the joint surface 5 of the wheel 1 as described above, and they are also provided symmetrically with respect to the axis, so that even if the joint surface 5 is locally deformed, the keys 7 are not completely deformed. The relative position between both adjacent wheels 1 can be maintained even more reliably within a two-dimensional plane. However, by providing at least three keys 7, when the cross section of the wheel 1 is a two-dimensional plane, it is possible to fix the relative positions of both adjacent wheels 1 on this two-dimensional plane. .

The method of attaching the key 7 will be described in detail with reference to FIG. This figure shows the mounting portion of the key 7 viewed from the radial direction in a state before the stacking bolt is tightened.

Each joint surface 5A, 5 of adjacent wheels 1A, 1B
The inner peripheral surfaces of the grooves 6A and 6B provided in B are not perpendicular to the bonding surfaces 5A and 5B, but are formed into slightly inclined taper surfaces (angle of inclination θ).
Further, the key 7 inserted into the grooves 6A, 6B is also formed so that its outer peripheral surface has a taper similar to the tapered surface of the grooves 6A, 6B.

When the keys 7 are inserted into the grooves 6A, 6B and the wheels 1A, 1B are combined, when the key 7 contacts the grooves 6A, 6B without any pressing force, the joint surfaces 5A, 1B of the wheels 1A, 1B, Gap δ between 5B
It is configured to produce. The gap δ
is set so that the deformation and eccentricity of the grooves 6A and 6B due to centrifugal force during operation are within the range of elastic deformation of the key 7.

Since this embodiment is configured as described above, the clamping force that can transmit the transmission torque and the shaft rigidity, that is, the rigidity of the shaft, are increased to increase the natural frequency, and the clamping force required from a rigid body that does not vibrate is reduced. If the wheels 1A and 1B are tightened from the state shown in FIG. 5 using the larger tightening force, the outer circumferential surface of the key 7 and the groove 6 There is no risk of creating a gap between the inner circumferential surface of the Therefore, the relative positions of adjacent wheels can be kept the same both when stationary and when rotating, and can be prevented from shifting in the radial direction.

In this embodiment, the transmission torque is basically transmitted by the frictional force of the joint surface 5 of the wheel 1, and is not shared by the key 7. Therefore, by providing the key 7 with a slit 8 on the surface facing the bottom of the groove 6 as shown in FIG.
It is possible to alleviate the repulsive force of the key 7 due to the pushing amount δ, and to prevent the tightening surface pressure of the wheel joint surface near the key 7 from decreasing. In this case, since the central portion of the key 7 having a sufficiently large cross-sectional area guides the deformation of the wheel in the radial direction, the key 7 can prevent adjacent wheels from shifting in the radial direction.

FIG. 6 shows a main part of another embodiment of the present invention, in which one of the adjacent wheels 1A and 1B, for example, a recess 10 with an inclined inner surface formed on the joint surface 5A of the wheel 1A is provided. , the other wheel 1B
A convex portion 5A having an outer peripheral surface having the same taper as the concave portion 10 is provided on the joint surface 5B, and the convex portion 5A is inserted into the concave portion 5B. The rest of the structure is the same as that of the embodiment shown in FIGS. 3 and 4, so drawings and explanations will be omitted. According to this embodiment configured in this way, the same effects as those of the previous embodiment can be obtained.

As explained above, according to the present invention, by restraining the relative displacement of each wheel in the circumferential direction,
It is possible to prevent adjacent wheels from being relatively displaced in the radial direction before and after the rotation of the rotor. Furthermore, since it is possible to prevent an increase in unbalance due to high-speed rotation and to reduce vibrations in the radial direction of the rotor, it is possible to prevent contact between the rotor and stator and damage to the bearings and rotor blades, thereby improving safety.

[Brief explanation of drawings]

1 and 2 are a cutaway perspective view of a conventional stacked rotor and a front view of the same wheel, and FIGS. 3 and 4 are a longitudinal sectional view and a front view of the same wheel showing an embodiment of the stacked rotor of the present invention,
FIG. 5 is a radially perpendicular sectional view of the wheel joint surface of the same embodiment, and FIG. 6 is a radially perpendicular sectional view of the wheel joint surface of another embodiment according to the present invention. 1...Wheel, 2...Stucking bolt,
5...Joint surface, 6...Groove, 7...Key, 8...Slit.

Claims (1)

[Scope of Claims] 1. A stacked rotor in which a plurality of wheels each having rotor blades attached to the outer circumferential surface are stacked in the axial direction, and these wheels are connected by a plurality of stacking bolts having end pieces at both ends. At least three grooves arranged at equal intervals in the circumferential direction on both adjacent wheels and on each joint surface of the end piece and the wheel, and at least three keys inserted into each of these grooves. What is claimed is: 1. A stacked rotor comprising: an inclined surface formed on the inner circumferential surface of these grooves and an outer circumferential surface of the key; and a slit provided on the outer circumferential surface of the key facing the groove bottom. 2. In a stacked rotor in which a plurality of wheels each having rotor blades attached to the outer circumferential surface are stacked in the axial direction and these wheels are connected by stacking bolts having end pieces at both ends, both of the adjacent wheels and the end Protrusions are provided on one side of each joint surface of the piece and the wheel, and recesses are provided at equal intervals in the circumferential direction on the other side, and inclined surfaces are formed on the inner peripheral surface of these recesses and the outer peripheral surface of the projections, and A stacked rotor characterized in that a slit is provided on the top surface of the convex portion.