JPS59213249A - Rotor for turbine generator - Google Patents

Abstract

PURPOSE:To improve the fatigue strength of a rotor for a turbine generator by forming slots at least at one side of the slot side and the wedge end side substantially at the center of the contacting part of the head of the slot with adjacent wedge end, thereby preventing the rotor from occurring with a fretting damage due to a bending deflection of the rotor. CONSTITUTION:A slot 10 is formed along the contacting surface 7A which contacts a slot on the end 9 of a wedge 9 inserted into the slot formed on a rotor core. When thus constructed, the rigidity of radial direction near the contacting end of the wedge 5, i.e., of perpendicular direction to the contacting surface 7A is reduced to set substantially uniformly the surface pressure of the contacting surface 7 near the contacting end, thereby moderating the concentration of the surface pressure of the contacting surface. The distribution of the surface pressure can be regulated by suitably setting a depth (l) of the slot 10 and a distance (h) from the contacting surface 7A.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a rotor with a plurality of slots provided in the axial direction on the outer peripheral surface of the rotor.
The present invention relates to a turbine generator rotor in which a coil and an arbitrary number of wedges are inserted into the lower and upper portions of these slots, and the coils are fixed in the slots by these wedges.

[Background of the invention]

As shown in FIGS. 1 to 3, a conventional rotor of this type has a slot 3 in a rotor core 2 formed integrally with a shaft 1.
A large number of coils 4 are provided in the axial direction, and a coil 4 is inserted into the lower part of these slots 3, and a spacer 6 is placed on this coil 4.
It has a structure in which an arbitrary number of wedges 5A are inserted into the upper part of the slot 3 so that an arbitrary number of wedges 5A are positioned through the wedges 5A.
This prevents the AK coil 4 from escaping from the slot 3 due to the force exerted by the rotation of the rotor.

The wedge 5A is formed in the shape of a ridge, but is generally formed in a dovetail shape as shown in FIGS. 2 and 3, and other shapes such as a single character shape and a Christmas tree shape are also used. Since an arbitrary number of these wedges 5AI'i can be inserted into the slots 3, a contact end 8 where the end surfaces of the adjacent wedges 5A touch each other is always formed on the contact surface 7' between the wedge 5A and the slot 3. Not only is surface pressure concentrated on this contact end 8 due to centrifugal force, but also when the rotor core 2 rotates with a curvature r due to its own weight or bending motion, as shown in FIG. A relative slippage δ occurs between the slot (rotor core 2) and the wedges 5A and (7). For this reason, large tensile and compressive stresses are concentrated in all nine directions on the rotor core 2 side of the contact end 8, which has the drawback of causing fretting damage and making fatigue cracks more likely to occur in this area.

In FIG. 4, the radius of the rotor is r. , when the length of the wedge 5A is t, the rotor core 2 has an upper point A and a lower point B.
When reaching , the edge 5A corresponding to the wedge end does not expand or contract because it is divided in the longitudinal direction. Therefore, each rotation of the rotor generates a relative slip 2δ (=-1) at the contact end 8 between the wedge 5A and the rotor core 2.

As mentioned above, the contact pressure is concentrated at the contact end 8, and it is well known that if a contact surface with high contact pressure is accompanied by relative slip, the fatigue strength will be significantly reduced due to fretting damage. That's a problem.

The surface pressure distribution on the contact surface 7' between the rotor core 2 and the wedge 5A is -1 as shown in FIG. 5, and it is clear from this figure that the surface pressure increases rapidly at the contact end m8. be.

If the corner pressure ends undergo relative sliding, as shown in FIG. I understand that. The relationship between the contact surface pressure and the fretting fatigue strength is shown in Figure 7. From this figure, the contact surface pressure has a large effect on the fretting fatigue position, and when the contact surface decreases to a certain extent, the fatigue strength increases. It can be seen that the strength decreases rapidly and the strength improves by '1'.

[Purpose of the invention]

In view of the above, the present invention alleviates the concentration of surface pressure at the contact surface between the slot and the ends of adjacent wedges inserted into the slots of the rotor core, and prevents the occurrence of fretting damage due to bending deflection of the rotor. The purpose of this invention is to provide a turbine engine rotor with high fatigue strength.

[Summary of the invention]

In order to achieve the above object, the present invention provides a turbine generator rotor in which a large number of slots are provided in the axial direction on the outer circumference of the rotor, and a coil and an arbitrary number of wedges are inserted into the lower and upper parts of these slots, respectively. The present invention is characterized in that a groove is provided on at least one side of the slot side and the wedge end surface side approximately at the center of the contact portion between the slot head and the adjacent wedge end.

[Embodiments of the invention]

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

In FIG. 8, reference numeral 5 denotes a wedge inserted into a slot (not shown) provided in the rotor core, and the end face 9 of this wedge 5 has a groove 1 along a contact portion]7A that contacts the slot.
0 is set. Other structures are shown in Figures 1 and 2.
Since it is the same as the conventional example shown in the figure, the drawing and explanation are omitted.

With this configuration, the wedge 5 as shown in FIG.
By reducing the rigidity in the radial direction near the contact end, that is, in the direction perpendicular to the contact surface 7A, and making the contact pressure on the contact surface 7 near the contact end almost uniform, the concentration of surface pressure on the contact surface can be alleviated. can. The surface pressure distribution can be adjusted by appropriately setting the depth t of the groove 10 and the distance from the contact surface 7A.

The second embodiment shown in FIG. 10 differs from the first embodiment (FIG. 8) in that a relief groove 11 is provided at the top of the end surface 9 of the wedge 5.
However, other structures are the same as in the first embodiment. With this configuration, the groove 10 can be easily processed and the strength of the end portion of the groove 10 can be prevented from decreasing.

The third embodiment shown in FIG. 11 has a groove 1 provided in the first embodiment.
0, a hollow groove 12 is provided on the end surface 9 of the wedge 5. With this configuration, it is possible to reduce the radial rigidity of the wedge contact end and alleviate the concentration of surface pressure on the contact surface between the slot and the wedge, as in the previous embodiment.

In the fourth embodiment shown in FIG. 12, a stress-relaxing groove 13 is provided in the portion of the contact surface 7B of the head of the slot 3 provided in the rotor core 2 that is in contact with the wedge end surface 9, and the wedge and slot 3 (rotor This prevents concentration of tensile and compressive stress in the sliding direction at the contact end due to relative sliding with the iron core 2). The state of contact between the wedge and the slot (rotor core 2) at the groove 13 is as shown in FIG. You can see that it is divided into two parts.

In the above embodiment, both end surfaces 9 of adjacent wedges 5 are in a dense layer state, but when the end surfaces 9 of adjacent wedges 5 are separated by a distance Δt as shown in FIG. Groove 13'
It is only necessary to make the width of Δt sufficiently longer than Δt.

FIG. 15 shows the surface pressure distribution at the contact end between the slot (rotor core 2) and the wedge 5 in the fourth embodiment (FIG. 12). This figure shows that the concentration of surface pressure at the contact ends (both ends of the groove 130) 8 between the wedge 5 and the rotor iron chisel 2 is significant, as in the conventional example, but this contact end 8 has a groove]3. As a result, relative slip between the wedge 5 and the rotor n<no02 as shown in FIG. 16 can be followed fairly flexibly. Therefore, since there is no longer a pawl-like action as in the past, it is possible to move around a rotor with high fatigue strength without the risk of tensile or compressive stress being particularly concentrated.

〔Effect of the invention〕

As explained above, according to the present invention, the concentration of blood pressure at the contact surface between the slot and the ends of adjacent wedges inserted into the slot provided in the rotor core is alleviated, and the damage caused by bending and deflection of the rotor is reduced. This can prevent the occurrence of fatigue and improve fatigue strength.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view of a conventional turbine generator rotor, Fig. 2 is a partially cutaway side view of Fig. 1, Fig. 3 is a perspective view showing the assembled state of the slot and wedge of Fig. 2, and Fig. 4 The figure is a front view of the deformation state of the rotor, and Figures 5 and 6 are diagrams showing the cross section of the contact end and its surface pressure distribution when using a conventional wedge, and the tensile and compressive stress distribution at the contact end. Figure, 7th
8, 10 and 11 are perspective views of the outside of the wedge of each embodiment of the turbine generator rotor of the present invention. FIG. 9 is a diagram showing the cross section of the contact end between the slot and the wedge end in the embodiment shown in FIG. 8 and its surface pressure distribution, and FIG. 12 is a perspective view of the slot portion in yet another embodiment according to the present invention. , Figures 13 and 14 are X-X in Figure 12.
The cross-sectional view, the modified cross-sectional view, and FIGS. 15 and 16 show the surface pressure distribution at the contact end of the slot and wedge of the embodiment shown in FIG. 12, and the tensile and compressive stress distribution at the contact portion.
This is a diagram showing this. 2... Rotor core, 3... Slot, 5... Wedge, 7A, 7B... Layer contact surface, 9... Wedge end surface, 10° 13... Groove, 11... Relief groove , 12...
Hodobu. Agent Masu filler Akio Takahashi No. 1 Diagram Fan Z Mouth VJJ Diagram VI4 Diagram 5 Diagram ￥16 Drawing pressure To Figure 11 Vi12 [21 Figure 13 Figure 13 ¥] 14 Figure 13' Figure 15 Shoulder 76 Figure madness

Claims (1)

[Scope of Claims] 1. In a turbine generator rotor in which a large number of slots are provided in the axial direction on the outer peripheral surface of the rotor, and a coil and an arbitrary number of wedges are inserted into the lower and upper parts of these slots, the slot head 1. A rotor for a turbine generator, characterized in that a groove is provided on at least one side of a slot side and a wedge end surface side approximately in the center of a contact portion between a portion and an adjacent wedge end portion. 2. The turbine generator rotor according to claim 1, wherein a relief groove is provided in the head portion of the wedge end portion. 3. The turbine generator rotor according to claim 1 or 2, characterized in that a hollow portion is provided at the end of the wedge.