Rotating electrical machine with cooling channels

A rotating electrical machine includes: a rotor core in which a slot passing therethrough is provided; a rotor winding which coil end portion is extended on the axially outer side than the core end face of the rotor core; a U-shaped channel which is arranged on the slot of the rotor core, is touched to come into contact with a bottom portion of the rotor winding, and is axially extended to be projected on the axially outer side than the core end face of the rotor core; a slot cell which insulates the rotor winding and the U-shaped channel from the rotor core; and an interposed piece arranged between the rotor windings at a portion more projected than the core end face of the rotor core. The projected end face of the U-shaped channel is arranged on the axially inner side than the projected end face of the interposed piece.

TECHNICAL FIELD

The present invention relates to rotating electrical machines such as turbine generators and, more particularly, relates to an improvement in ventilation cooling performance in a rotor of a rotating electrical machine.

BACKGROUND ART

In a conventional rotating electrical machine having a cylindrical rotor, a slot axially passing through a rotor core is provided in plural numbers in the circumferential direction of the rotor core, a rotor winding that is a field winding is wound in a distributed winding manner and placed in each slot thereof, and a coil end portion of the rotor winding is arranged to be more projected than the core end face of the rotor core.

Furthermore, in the rotating electrical machine having the cylindrical rotor which is provided with a space by a narrow subslot and/or a U-shaped channel that supports the rotor winding on a slot bottom portion of each slot provided in the rotor core, refrigerant gas is ventilated in the space to cool the rotor winding.

In the conventional rotating electrical machine having the cylindrical rotor, the rotor having the subslot on the bottom portion of the slot of the rotor core improves cooling performance by arranging a streamlined body wedge block adjacent to the subslot. (For example, see Patent Document 1.)

Furthermore, in the rotor having the U-shaped channel on the bottom portion of the slot of the rotor core, a structure is made such that the projected end face of the U-shaped channel, which is more projected than the core end face of the rotor core, is axially projected than the projected end face of an adjacent interposed piece that is more projected than the core end face of the rotor core and the refrigerant gas becomes difficult to flow.

By the way, as the rotating electrical machine provided with the rotor having the U-shaped channel on the bottom portion of the slot of the rotor core, there is a configuration shown in, for example,FIG. 9andFIG. 10. A rotor winding3is placed in a slot2of a rotor core1and a coil end portion of the rotor winding3is extended on the axially outer side than the core end face1aof the rotor core1. A U-shaped channel4, which is touched to come into contact with a bottom portion of the rotor winding3and is axially extended, is arranged on a slot bottom portion2aof the slot2of the rotor core1; a projected end face4aof the U-shaped channel4is projected on the axially outer side than the core end face1aof the rotor core1; and refrigerant gas is ventilated in the U-shaped channel4to cool the rotor winding3.

A slot cell5is placed in the slot2of the rotor core1; the rotor winding3and the U-shaped channel4in the slot2of the rotor core1are insulated from the rotor core1by the slot cell5; the axial end face of the slot cell5is axially more projected than the core end face1aof the rotor core1to insulate. In order to protect the slot cell5, for example, the U-shaped channel4is projected on the axially outer side so that the projected end face4aof the U-shaped channel4is the same as the projected end face of the slot cell5.

An interposed piece6which is arranged between the rotor windings3at a portion more projected than the core end face1aof the rotor core1is more projected than the core end face1aof the rotor core1in a predetermined dimension, and is arranged to be extended in a straddle fashion over the rotor winding3and the U-shaped channel4to maintain each interval between the rotor windings3and between the U-shaped channels4.

The projected end face4aof the U-shaped channel4is arranged to be projected on the axially outer side by a value of P than the projected end face6aof the interposed piece6in order to easily confirm a positional relationship after assembling peripheral components. Then, as shown by an arrow R1, the refrigerant gas is ventilated from the projected end face4aside of the U-shaped channel4into the inside of the U-shaped channel4so as to cool the rotor winding3.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In the aforementioned conventional rotating electrical machine, the projected end face4aof the U-shaped channel4is arranged to be projected on the axially outer side than the projected end face6aof the interposed piece6by the value of P in order to easily confirm the positional relationship after assembling the peripheral components. The projected end face4aof the U-shaped channel4is more projected than the projected end face6aof the interposed piece6; and thus, the position of the U-shaped channel4can be visually confirmed; and mounting of the U-shaped channel4to a predetermined position is completed by measuring the dimension between the projected end face4aof the U-shaped channel4and the projected end face6aof the interposed piece6and setting the measured dimension to be the value of P.

As described above, the projected end face4aof the U-shaped channel4is projected on the axially outer side than the projected end face6aof the interposed piece6; and accordingly, a problem exists in that the refrigerant gas into the inside of the U-shaped channel4is difficult to flow.

More specifically, the refrigerant gas is ventilated into the inside of the U-shaped channel4as shown by the arrow R1. However, since the projected portion of the U-shaped channel4serves as a wall, the refrigerant gas shown by an arrow R2is not ventilated into the inside of the U-shaped channel4; and accordingly, a problem exists in that the ventilation amount of the refrigerant gas into the inside of the U-shaped channel4is limited and cooling performance of the rotor winding3is not sufficient.

The present invention has been made to solve the above described problem, and an object of the present invention is to provide a rotating electrical machine that can improve cooling performance by providing the projected end face of a U-shaped channel on the axially inner side than the projected end face of an interposed piece.

Means for Solving the Problems

According to the present invention, there is provided a rotating electrical machine including: a rotor core in which a slot axially passing therethrough is provided in plural numbers in a circumferential direction; a rotor winding which is placed in the slot provided in the rotor core, and whose coil end portion is extended on the axially outer side than the core end face of the rotor core; a U-shaped channel which is arranged on a slot bottom portion of the slot of the rotor core, is touched to come into contact with a bottom portion of the rotor winding, and is axially extended to be projected on the axially outer side than the core end face of the rotor core; a slot cell which is placed in the slot of the rotor core, and insulates the rotor winding and the U-shaped channel in the slot of the rotor core from the rotor core; and an interposed piece arranged between the rotor windings at a portion more projected than the core end face of the rotor core. The projected end face of the U-shaped channel is arranged on the axially inner side than the projected end face of the interposed piece.

Advantageous Effect of the Invention

According to the rotating electrical machine of the present invention, the projected end face of the U-shaped channel is provided on the axially inner side than the projected end face of the interposed piece, whereby there can be obtained the rotating electrical machine which can reduce pressure loss at the projected end face portion of the U-shaped channel and can improve cooling performance.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, Embodiment 1 of the present invention will be described on the basis ofFIG. 1toFIG. 5. Then, in each of the drawings, identical or equivalent members and portions will be described with the same reference numerals (and letters) assigned thereto.FIG. 1is a bird s-eye view showing a rotating electrical machine according to Embodiment 1 of the present invention.FIG. 2is a sectional view showing the rotating electrical machine according to Embodiment 1 of the present invention.FIG. 3is a relevant part sectional view showing a relevant part of the rotating electrical machine according to Embodiment 1 of the present invention.FIG. 4is a bird's-eye view showing a relevant part of the rotating electrical machine according to Embodiment 1 of the present invention.FIG. 5is a sectional view taken along the line V-V ofFIG. 4showing the rotating electrical machine according to Embodiment 1 of the present invention.

In these respective drawings, a rotor10of the rotating electrical machine includes: a rotor core12positioned in a central portion of a rotor shaft11; a slot13which axially passes through the rotor core12and is provided in plural numbers in the circumferential direction of the rotor core12; a rotor winding14which is placed in each slot13, and whose coil end portion14bis arranged to be extended on the axially outer side than the core end face of12aof the rotor core12; a U-shaped channel15which is arranged on a slot bottom portion13aof the slot13of the rotor core12, is touched to come into contact with a bottom portion of the rotor winding14, and is axially extended to be projected on the axially outer side than the core end face of12aof the rotor core12; a slot cell16which is placed in the slot13of the rotor core12, and insulates the rotor winding14and the U-shaped channel15in the slot13of the rotor core12from the rotor core12; and an interposed piece17arranged between the rotor windings14at a portion more projected than the core end face of12aof the rotor core12. The interposed piece17is extended to, for example, between the U-shaped channels15.

The projected end face15aof the U-shaped channel15is arranged on the axially inner side than the projected end face17aof the interposed piece17to reduce pressure loss of ventilation of refrigerant gas at the projected end face15aportion of the U-shaped channel15. Then, a chamfered portion15bis formed on the projected end face15aportion of the U-shaped channel15to further reduce the pressure loss of the ventilation of the refrigerant gas to the projected end face15aportion of the U-shaped channel15. Furthermore, a chamfered portion17bis also formed on the projected end face17aportion of the interposed piece17to further more reduce the pressure loss of the ventilation of the refrigerant gas to the projected end face15aportion of the U-shaped channel15. The projected end face15aof the U-shaped channel15is arranged to be positioned on the axially inner side than the chamfered portion17bof the projected end face17aportion of the interposed piece17.

A retaining ring18that retains the coil end portions of the rotor windings14is arranged on the rotor shaft11; and the rotor windings14placed in the slots13of the rotor core12are each fixed by a rotor wedge19. The rotor winding14is formed with radial coil ventilation holes14aeach communicated with the inside of the U-shaped channel15; and the rotor wedge19is formed with wedge ventilation holes19aeach communicated with the coil ventilation hole14aof the rotor winding14.

Next, operation will be described. The refrigerant gas is flown in from between the rotor shaft11and the retaining ring18, and is axially ventilated from the projected end face15aportion of the U-shaped channel15into the inside of the U-shaped channel15. Then, the refrigerant gas is radially ventilated from the U-shaped channel15to the coil ventilation holes14aof the rotor winding14, and is flown out from the wedge ventilation holes19aof the rotor wedge19to the surface of the rotor10to cool the rotor winding14.

In this Embodiment 1, confirmation of the mounting position of the U-shaped channel15can be confirmed by mounting the U-shaped channel15so as to be a value of Q that is the projection amount of the projected end face15aof the U-shaped channel15from the core end face of12aof the rotor core12; and therefore, the projected end face15aof the U-shaped channel15can be arranged on the axially inner side than the projected end face17aof the interposed piece17and the pressure loss of the ventilation of the refrigerant gas at the projected end face15aportion of the U-shaped channel15can be reduced.

More specifically, the refrigerant gas is ventilated into the inside of the U-shaped channel15as shown by an arrow R3and an arrow R4, the refrigerant gas of the arrow R3is easily flown into the inside of the U-shaped channel15by the chamfered portion15bformed on the projected end face15aportion of the U-shaped channel15; and therefore, as compared to the aforementioned conventional rotating electrical machine, the ventilation amount of the refrigerant gas is R3>R1. Then, the projected end face15aof the U-shaped channel15is arranged on the axially inner side than the chamfered portion17bof the projected end face17aof the interposed piece17and therefore the refrigerant gas of R4can be ventilated into the inside of the U-shaped channel15in this Embodiment, although the refrigerant gas of R2cannot be ventilated into the inside of the U-shaped channel4in the aforementioned conventional rotating electrical machine. Therefore, as compared to the aforementioned conventional rotating electrical machine, the ventilation amount of the refrigerant gas can be (R3+R4)>R1, the ventilation amount of the refrigerant gas into the inside of the U-shaped channel15can be considerably increased, and cooling performance of the rotor winding14can be remarkably improved.

Then, the chamfered portion15bis formed on the projected end face15aportion of the U-shaped channel15, the chamfered portion17bis also formed on the projected end face17aportion of the interposed piece17, and the pressure loss of the ventilation of the refrigerant gas to the projected end face15aportion of the U-shaped channel15is further reduced; and therefore, the cooling performance of the rotor winding14can be further more improved.

The pressure loss of the ventilation of the refrigerant gas to the projected end face15aportion of the U-shaped channel15is confirmed by computational fluid dynamics (CFD) analysis and a model verification test. As a model, modeling is performed from an inlet of the retaining ring→the projected end face portion of the U-shaped channel→to the inside (about 1 m) of the U-shaped channel; and as a condition, the confirmation is performed by a rotational frequency of 3600 min−1(rated rotational frequency), an inlet air velocity of about 20 m/s, and air serving as the refrigerant gas. As a result, when the pressure loss at the projected end face4aportion of the aforementioned conventional U-shaped channel4is 100%, the pressure loss at the projected end face15aportion of the U-shaped channel15in this Embodiment becomes about 35% and about 65% of the pressure loss can be reduced.

As described above, since the pressure loss of the ventilation of the refrigerant gas to the projected end face15aportion of the U-shaped channel15can be considerably reduced, the refrigerant gas can be efficiently ventilated into the inside of the U-shaped channel15. This can remarkably increase the flow-in amount of the refrigerant gas into the inside of the U-shaped channel15and can remarkably improve the cooling performance of the rotor winding14.

Furthermore, the projected end face15aof the U-shaped channel15is arranged on the axially inner side than the projected end face17aof the interposed piece17; and thus, the U-shaped channel15can be shortened and a reduction in costs can be achieved.

Embodiment 2 of the present invention will be described on the basis ofFIG. 6.FIG. 6is a bird's-eye view showing a relevant part of a rotating electrical machine according to Embodiment 2 of the present invention.

In this Embodiment 2, there is provided a block20that covers a U-shaped channel15at an adjacent portion of an interposed piece17extended to between U-shaped channels15; a chamfered portion20bis formed on a projected end face20aof a block20; and a projected end face15aof the U-shaped channel15is arranged to be positioned on the axially inner side than the chamfered portion20bof the projected end face20aof the block20.

Also in this Embodiment 2, the projected end face15aof the U-shaped channel15is arranged to be positioned on the axially inner side than the chamfered portion20bof the projected end face20aof the block20; and thus, pressure loss of ventilation of refrigerant gas to the projected end face15aportion of the U-shaped channel15is reduced and therefore the same effect as the aforementioned Embodiment 1 can be exhibited.

Embodiment 3 of the present invention will be described on the basis ofFIG. 7.FIG. 7is a bird's-eye view showing a relevant part of a rotating electrical machine according to Embodiment 3 of the present invention.

In the aforementioned Embodiment 1, the description has been made on the case where the chamfered portion15bis formed on the projected end face15aportion of the U-shaped channel15and the chamfered portion17bis formed on the projected end face17aportion of the interposed piece17. However, this Embodiment 3 is configured such that a chamfered portion is formed on only either a projected end face15aportion of a U-shaped channel15or a projected end face17aportion of an interposed piece17; and as an example, the drawing represents that a chamfered portion15bis not formed on the projected end face15aportion of the U-shaped channel15, but a chamfered portion17bis formed on only the projected end face17aportion of the interposed piece17.

Also in this Embodiment 3, since the projected end face15aof the U-shaped channel15is arranged to be positioned on the axially inner side than the projected end face17aof the interposed piece17, pressure loss of ventilation of refrigerant gas to the projected end face15aportion of the U-shaped channel15can be reduced and therefore the same effect as the aforementioned Embodiment 1 can be exhibited.

Embodiment 4 of the present invention will be described on the basis ofFIG. 8.FIG. 8is a bird's-eye view showing a relevant part of a rotating electrical machine according to Embodiment 4 of the present invention.

In the aforementioned Embodiment 1, the description has been made on the case where the chamfered portion15bis formed on the projected end face15aportion of the U-shaped channel15and the chamfered portion17bis formed on the projected end face17aportion of the interposed piece17. However, in this Embodiment 4, a chamfered portion is not formed on a projected end face15aportion of a U-shaped channel15and a projected end face17aportion of an interposed piece17.

Also in this Embodiment 4, since the projected end face15aof the U-shaped channel15is arranged to be positioned on the axially inner side than the projected end face17aof the interposed piece17, pressure loss of ventilation of refrigerant gas to the projected end face15aportion of the U-shaped channel15can be reduced and therefore the same effect as the aforementioned Embodiment 1 can be exhibited.

Incidentally, the present invention can freely combine the respective embodiments and appropriately modify and/or omit the respective embodiments, within the scope of the present invention.

INDUSTRIAL APPLICABILITY

The present invention is suitable for actualizing a rotating electrical machine which can reduce pressure loss of refrigerant gas at a projected end face portion of a U-shaped channel and can improve cooling performance.