JPH0156622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor for a rotating electrical machine such as a turbine generator.

As shown in FIGS. 1 and 2, the rotor of a rotating electrical machine, for example, a turbine generator, has a rotor shaft 1 which is cylindrical and has a plurality of grooves 2 and teeth 7 formed in the axial direction of its circumferential surface.
Groove inserts such as a conductor 3 and an insulator 4 are inserted into the groove 2 of the groove 2, and a wedge 5 is provided at the opening of the groove 2 to prevent these inserts from flying out due to centrifugal force during rotation. is provided. By the way, in general, the dimensions of the grooves 2 are not necessarily the same for all grooves; for example, as shown in FIG. The depth of the groove 2b is shallower than that of the other grooves 2b. Therefore, the amount of the conductor 3, insulator 4, etc. to be inserted is also smaller than the shallow groove 2a near the magnetic pole.
There are more deep grooves 2b in the other grooves, so when the rotor rotates, the centrifugal force due to objects inserted into the grooves, wedges, etc. will be larger in the other grooves 2b than in the grooves 2a closer to the magnetic poles. .

Now, as mentioned above, the wedge 5 is provided for the purpose of preventing the objects inserted into the groove, such as the conductor 3 and the insulator 4, from flying out due to the centrifugal force caused by the rotation of the rotor shaft 1, and as shown in FIG. The contact surface 15 between the wedge 5 and the teeth 7 formed on the rotor shaft 1, on which centrifugal force acts during rotation, is formed on the rotor shaft 1 for advantageous strength.
The figure shows an example of such a wedge 5 in a state where it is in contact with teeth 7 on the rotor shaft 1 during rotation.
In this figure, the contact surface 15 between the wedge 5 and the tooth 7 of the rotor shaft 1
is the radial direction of rotor axis 1 and θ (θ is not 90 degrees)
It has an angle of Now let us consider the force acting on this contact surface 15 when the rotor is rotating at an angular velocity ω in FIG. During rotation, this contact surface 1
The forces acting on 5 are centrifugal force F〓 and reaction force of rotor shaft 1
It is N〓. The centrifugal force F〓 acts in the radial direction of the rotor shaft 1, and the reaction force N〓 acts perpendicularly to the contact surface 15. Mechanically, these forces must be balanced, so the following equation holds.

F〓=n〓+n〓=2n〓 Here, n〓 is the radial component of the reaction force N〓. Further, if the component force in the direction perpendicular to the radial direction (hereinafter referred to as circumferential force) is f〓, these component forces are given by the following equation.

n〓=N〓・sinθ f〓=N〓・cosθ Therefore, when the centrifugal force F〓 acts, the reaction force N〓 and its component forces n〓 and f〓 acting on the contact surface 15 in Fig. 3 are as follows. It is given by Eq.

N〓=(F〓/2)・sinθ n〓=F〓/2 f〓=(F〓/2)/tanθ In other words, the contact surface 15 between the wedge 5 and the tooth 7 of the rotor shaft 1
When centrifugal force F〓 acts on the rotor shaft, a force of f〓=(F〓/2)/tanθ acts on the contact surface 15 of the rotor shaft in a direction perpendicular to the radial direction of 1, that is, in the circumferential direction. This is the force by which the teeth 7 of the rotor shaft 1 and the wedges 5 press against each other.

Now, as mentioned above, generally the depths of the plurality of grooves 2 provided on the outer circumferential portion of the rotor shaft 1 are not necessarily all the same, and for example, in the case of Fig. 2, the depth is generally determined by the contents stored in the grooves. Centrifugal force is caused by shallow grooves 2 near the magnetic poles.
The other deep groove 2b is larger than the groove a. Therefore, if the angles θ between the wedges 5 and the teeth 7 of the rotor shaft 1 and the radial direction of the rotor shaft 1 are all the same as shown in FIG. , reaction force N ₁ 〓 due to centrifugal force F ₁ 〓 acting on the contact surface 15a between the wedge 5a of the groove 2a near the magnetic pole and the tooth 7
The circumferential force f ₁ 〓 from and the wedge 5b of the adjacent groove 2b
The reaction force N 2 due to the centrifugal force F ₂ 〓 acting on the contact surface 15b between the teeth 7 and the circumferential force f _{2 〓} from the grooves 2a and 2b
It acts on the tooth 7 between them, and eventually the tooth 7 receives circumferential force f ₁ 〓, f ₂ 〓
The difference between them is Δf〓=f ₂ 〓−f ₁ 〓 (however, f ₂ 〓＞f ₁ 〓),
A bending couple will be applied to the magnetic pole side. The value of this circumferential force difference Δf〓 varies depending on the number of rotations, differences in groove depth, etc., but it is usually large enough to cause bending deformation in the tooth 7, and is It is often experienced that the wedge 5a of the groove 2a near the magnetic pole is firmly sandwiched between the tooth 7 and the magnetic pole part 8 due to the bending deformation of the tooth 7 in the direction of the magnetic pole, making it difficult to extract the wedge. Furthermore, if the groove depths are different or the rotational speed is large, the bending stress at the groove bottom also increases, and from the viewpoint of strength and reliability, it is desired to reduce the circumferential force difference Δf〓.

It is an object of the present invention to provide a highly reliable rotor for a rotating electrical machine by significantly reducing the circumferential force difference Δf〓.

FIG. 5 is a partial sectional view of a rotor showing an embodiment to which the present invention is applied, and the main symbols are the same as those in FIG. 4. In this example, the contact surfaces 15a, 15b between the wedges 5a, 5b and the teeth 7 of the rotor shaft 1 are
The angle formed with respect to the radial direction is close to the magnetic pole, and the angle θ ₁ in the groove 2a where the centrifugal force is small is smaller than the angle θ ₂ in the adjacent groove 2b where the centrifugal force is large, and the angles θ ₁ and θ ₂ are For example, the tangent ratio (tanθ ₁ /tanθ ₂ ) is the contact surface 15a, 15b at the rated rotation speed _ωo .
The ratio of the centrifugal force acting on the F ₁ /F _{2 is the same as that of the centrifugal force F 1 /F 2} . That is, tanθ ₁ /tanθ ₂ =F ₁ /F ₂ =m ₁ r ₁ ω _o ² /m ₂ r ₂ ω _o ² = m ₁ r ₁ /m ₂ r ₂ m ₁ m ₂ : Mass in groove r ₁ r ₂ : Constructed to be the radius of rotation of the mass in the groove.

Next, the effects of the present invention will be explained. First, when the rotor is rotating at an angular velocity ω, the centrifugal force acting on each contact surface is different as shown in Fig. 5, and the centrifugal force in the grooves 2a and 2b is
If F ₁ 〓, F ₂ 〓, then the circumferential forces f ₁ 〓, f ₂ 〓 acting on the contact surfaces 15a, 15b between one side of the wedge and the tooth 7 due to the centrifugal forces F ₁ 〓, F ₂ 〓, respectively. f ₁ 〓=(F ₂ 〓/2)/tanθ ₁ , f ₂ 〓=(F ₂ 〓/2)/ta
nθ ₂ is obtained. As mentioned above, if the values of f ₁ 〓 and f ₂ 〓 are different, a bending force is generated in tooth 7, so ideally f ₁ 〓
Since it is desirable that = f ₂ 〓, tanθ ₁ /tanθ ₂ =F ₁ 〓/F ₂ 〓.

That is, the ratio of the tangents of the angles θ ₁ and θ ₂ formed by the contact surface 15a between the tooth 7 and the wedge 5a and the contact surface 15b between the tooth 7 and the wedge 5b with the radial direction of the rotor axis (tanθ ₁ /tanθ ₂ ) If the ratio of the centrifugal forces acting on the contact surfaces 15a and 15b (F ₁ 〓/F ₂ 〓) while the rotor is rotating at the angular velocity ω, then the tooth 7 will receive a circumferential force due to the centrifugal force, i.e. No bending couple acts.

In this example, as can be seen from the above equation, θ ₁ and θ ₂ are configured so that tanθ ₁ /tanθ ₂ = F ₁ /F ₂ = m ₁ r ₁ / m ₂ r ₂ , so the rotation At the angular velocity ω, F ₁ 〓／F ₂ 〓={m ₁・r ₁・ω ² }／{m ₂・r ₂・ω ² } = (m ₁・r ₁ )/(m ₂・r ₂ )= tanθ ₁ /tanθ ₂ , and the contact surfaces 15a and 15b are independent of the rotation speed.
The difference in circumferential force due to the centrifugal force acting on the teeth 7 can be eliminated, and no bending couple will act on the teeth 7.

The basic structure of the present invention has been explained above, but in the case of a rotor shaft of a turbine generator, for example, there are differences in the depth of the grooves, and even within the same groove, for example, wedges made of different materials may be formed in the axial direction. may be arranged in In such a case, for example, the weight difference between the wedges will affect the centrifugal force, so even if the teeth are the same, the amount and direction of the bending couple will change depending on the axial position. FIG. 6 is a perspective view from the outer periphery of the rotor shaft for explaining an embodiment in such a case. In this case, the bending force couple acting on the tooth 7 is naturally different between the region 13 and the region 14. Even in such a case, if the spirit of the present invention is utilized, it is possible to deal with the problem by changing the angle of the contact surface between the wedge and the tooth.

As explained above, according to the present invention, the ratio of the tangent of the angle between the contact surfaces of the teeth and the wedges with the radial direction of the rotor axis is determined by the centrifugal force acting on each contact surface at a predetermined rotation speed of the rotor. Since the structure is configured to match the force ratio, the circumferential component force due to centrifugal force acting on the contact surface is canceled out regardless of the rotation speed, and the bending force acting on the teeth can be canceled regardless of the rotation speed. It is possible to provide a rotor for a rotating electrical machine with high performance.

[Brief explanation of drawings]

Figure 1 is a front view showing the rotor of a rotating electrical machine, Figure 2
The figure is a sectional view taken along the - line in Figure 1, Figure 3 is an explanatory diagram showing the state in which the wedge is in contact with the tooth during rotation, and Figure 4 is the force acting on the contact surface between the wedge and the tooth and its amount. FIG. 5 is an explanatory diagram for explaining the force and force acting on the contact surface between the wedge and teeth of the rotor of the rotary electric machine according to the present invention, and FIG. FIG. 3 is a perspective view of a rotor showing an embodiment of the present invention. 1... Rotor shaft, 2, 2a, 2b... Groove, 5,
5a, 5b... Wedge, 7... Teeth, 15, 15a, 1
5b...Contact surface, F〓, F ₁ 〓, F ₂ 〓...Centrifugal force,
N〓, N ₁ 〓, N ₂ 〓... Reaction force, f〓, f ₁ 〓, f ₂ 〓... Circumferential force, θ, θ ₁ , θ ₂ ... The contact surface between the wedge and the tooth is the rotor The angle made with respect to the radial direction of the axis.

Claims (1)

[Claims] 1. A rotor shaft having a cylindrical shape and having a plurality of grooves and teeth formed in the axial direction of the circumferential surface, a groove insert housed in the groove, and a groove insert inserted into the opening of the groove. In a rotor for a rotating electrical machine, the rotor is provided with a wedge for holding the rotor, and the centrifugal force acting on each contact surface between the teeth and the wedge is not necessarily uniform due to the rotation of the rotor shaft, and each contact surface is connected to the rotor shaft. A rotor for a rotating electric machine, characterized in that the ratio of the tangent of the angle formed with the radial direction of the rotor is formed to match the ratio of the centrifugal force acting on each of the contact surfaces.