Slip ring device and rotary electric machine using the same

A first slip ring and a second slip ring are put from both ends of a slip ring shaft, respectively, and are attached by shrink-fitting, the slip ring shaft being provided separately from a rotor shaft; the shaft diameter of a lead connecting portion is formed larger than the shaft diameters of respective slip ring attaching portions; and a coupling, which is attached by shrink-fitting to a shaft end portion on the rotor shaft side of the slip ring shaft after the first slip ring is attached by shrink-fitting, is provided.

TECHNICAL FIELD

The present invention relates to a slip ring device and a rotary electric machine using the same, the slip ring device having slip rings for electrically connecting to an external device to excite a rotor of the rotary electric machine and having radial leads for flowing electricity in a radial direction of the rotor from the slip rings.

BACKGROUND ART

As a rotary electric machine using a conventional slip ring device, for example, there is one as shown inFIG. 11. A turbine generator1serving as a rotary electric machine includes those broadly divided into a frame2, a stator3, a rotor10, and a slip ring device portion15.

The stator3has a stator core4wound by a stator coil6and is fixed to an inner peripheral portion of a frame2. The rotor10has magnetic poles12concentrically wound by a rotor coil13and a directly coupled portion14. A rotational shaft11of the rotor10is removably supported by respective bearings7a,8ain respective brackets7,8attached to the frame2.

Slip rings18are insulated and held in the vicinity of a shaft end portion extended in an end portion of the outside of the machine on the side opposite to the directly coupled side of the rotational shaft11. A current collecting portion16of the slip ring device portion15includes the slip rings18and brushes19which come in contact with the periphery of the slip rings18. The rotor coil13is connected to the slip rings18by connection conductors (both are not shown in the drawing) disposed in grooves on the periphery of the rotational shaft11.

The current collecting portion16includes the slip rings18, the brushes19, brush holders20, and an insulation protective plate21. The slip rings18are made of alloy steel and are fitted on insulators17each formed in a ring shape on the vicinity of the shaft end portion extended in the end portion of the outside of the machine on the side opposite to the directly coupled side of the rotational shaft11.

Furthermore,FIG. 12andFIG. 13show specific examples of a conventional slip ring structure, which is provided with a rotor shaft end portion52extended from a rotor shaft51to outside the machine. The rotor shaft end portion52is formed by machining from a structure integrated with the rotor shaft51. Then, the rotor shaft end portion52and the rotor shaft51are formed with a hollow hole53which is formed in their central portions to the vicinity of a coil end.

The rotor shaft end portion52serves as an attaching portion of the slip ring structure. The rotor shaft end portion52is arranged with, for example, a first slip ring54on the positive pole side and a second slip ring55on the negative pole side. The first slip ring54is disposed on a first slip ring attaching portion52aon the rotor shaft51side; and the second slip ring55is disposed on a second slip ring attaching portion52bon the side opposite to the rotor shaft51, that is, on the shaft end side of the rotor shaft end portion52. As described above, the first slip ring54on the positive pole side and the second slip ring55on the negative pole side are needed.

The rotor shaft end portion52is formed with a lead connecting portion56between the first slip ring54and the second slip ring55. The lead connecting portion56is formed with a first radial lead placing hole58in which a first radial lead57is placed and a second radial lead placing hole60in which a second radial lead59is placed.

A crescent shaped first axial lead61to be connected to the first radial lead57and a crescent shaped second axial lead62to be connected to the second radial lead59are attached by insertion in the hollow hole53which is formed in the central portions of the rotor shaft end portion52and the rotor shaft51, the hollow hole53being formed to the vicinity of the coil end. Then, an insulator between leads63is inserted between the first axial lead61and the second axial lead62; and an insulator64is inserted between the hollow hole53and the first axial lead61and between the hollow hole53and the second axial lead62. An insulator65is provided at end portions of the first axial lead61and the second axial lead62.

The first slip ring54is connected to the first radial lead57via a first slip ring lead66and the second slip ring55is connected to the second radial lead59via a second slip ring lead67.

By the way, the supply of electricity from an external portion outside the machine and the extraction of electricity from the rotor to the external portion are the flow of the electricity as shown by arrows inFIG. 12. The supply of the electricity from the external portion outside the machine flows to the first slip ring54on the positive pole side via the brushes (not shown in the drawing). The electricity flown to the first slip ring54flows to the first radial lead57via the first slip ring lead66. The electricity flown to the first radial lead57is supplied to the rotor coil via the first axial lead61.

The extraction of the electricity from the rotor to the external portion flows from the rotor coil to the second axial lead62. The electricity flown to the second axial lead62flows to the second radial lead59. The electricity flown to the second radial lead59flows to the second slip ring55on the negative pole side via the second slip ring lead67. The electricity flown to the second slip ring55is extracted to the external portion via the brushes (not shown in the drawing).Patent Document 1: Japanese Unexamined Patent Publication No. 2003-164111Patent Document 2: Japanese Unexamined Patent Publication No. H6-237558Patent Document 3: Japanese Unexamined Patent Publication No. H8-242554Patent Document 4: Japanese Unexamined Patent Publication No. H8-51765Patent Document 5: Japanese Unexamined Patent Publication No. S59-216445Patent Document 6: Japanese Unexamined Patent Publication No. S60-109744Patent Document 7: Japanese Unexamined Utility Model Publication No. S59-176365

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

As described above, conventionally, in the rotary electric machine, the rotor shaft51is provided with the bearings to support the rotor. The rotor shaft end portion52is extended outside the machine from a bearing portion of the rotor shaft51. The rotor is adjusted in alignment so that a certain level of load is exerted on the bearings; and accordingly, bending stress is generated in the rotor.

Furthermore, in the case of the arrangement of a gas turbine, a generator, and a steam turbine (CGS), torsional torque due to the output of the steam turbine is loaded to the rotor shaft end portion52of the rotor shaft51on which the slip ring structure is disposed; and therefore, torsional stress is generated during operation.

The first radial lead placing hole58and the second radial lead placing hole60for the supply of the electricity to the rotor coil and the extraction of the electricity from the rotor coil are formed in the rotor shaft end portion52of the rotor shaft51on which the slip ring structure is disposed; and accordingly, such holes become sections where the stress is concentrated. Therefore, the sections of the first radial lead placing hole58and the second radial lead placing hole60tend to be the weakest sections.

In the generator of such CGS arrangement, during a fault by any chance such as a sudden short-circuit, high torsional torque is loaded to the rotor shaft end portion52of the rotor shaft51on which the slip ring structure is disposed; and therefore, generally, the rotor shaft51on which the rotor coil is placed and the rotor shaft end portion52on which the slip ring structure is disposed are manufactured in an integrated structure.

By the way, the first slip ring54on the positive pole side and the second slip ring55on the negative pole side are needed; and, the first slip ring54and the second slip ring55are attached to the rotor shaft end portion52in the following way, the rotor shaft end portion52being manufactured in the integrated structure with the rotor shaft51.

The first slip ring54and the second slip ring55are attached by shrink-fitting to the rotor shaft end portion52having a slightly larger diameter than the inner diameters of the respective slip rings. The rotor shaft end portion52and the rotor shaft51are the integrated structure; and therefore, the first slip ring54and the second slip ring55need to be put from the extending shaft end side of the rotor shaft end portion52.

First, as shown inFIG. 14, the first slip ring54is put from the extending shaft end side of the rotor shaft end portion52; the first slip ring54is passed over the second slip ring attaching portion52band is further passed over the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed; and the first slip ring54is attached to the first slip ring attaching portion52aby shrink-fitting.

Next, the second slip ring55is similarly put from the extending shaft end side of the rotor shaft end portion52and is attached to the second slip ring attaching portion52bby shrink-fitting. As described above, the first slip ring54and the second slip ring55are attached by shrink-fitting while sandwiching the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed.

As described above, the first slip ring54is put from the extending shaft end side of the rotor shaft end portion and is shrink-fitted at the position beyond the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed; and accordingly, much labor and time are required for its shrink-fitting work.

Furthermore, a problem exists in that the shaft diameter of the rotor shaft end portion52including the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed cannot be larger than the shrink-fitting diameters of the first slip ring54and the second slip ring55. More particularly, the lead connecting portion56is formed with the first radial lead placing hole58and the second radial lead placing hole60; and therefore, such holes become the sections where the stress is concentrated. Therefore, the sections of the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed are the weakest sections.

In addition, the diameters of the first slip ring54and the second slip ring55are restricted by the peripheral velocity of the brushes (not shown in the drawing); and therefore, the outer diameters of the first slip ring54and the second slip ring55are restricted. Then, along with that, the shaft diameter of the rotor shaft end portion52including the lead connecting portion56where the first radial lead placing hole58and the second radial lead placing hole60are formed cannot be also large; and thus, it becomes difficult to improve strength.

The present invention has been made to solve the problem described above, and an object of the present invention is to provide a slip ring device and a rotary electric machine using the same; in the slip ring device, a first slip ring and a second slip ring are put from both ends of a slip ring shaft, respectively, and are attached by shrink-fitting, the slip ring shaft being provided separately from a rotor shaft, and the shaft diameter of a lead connecting portion where a first radial lead placing hole and a second radial lead placing hole of the slip ring shaft are formed is formed larger than the shaft diameters of a first slip ring attaching portion and a second slip ring attaching portion.

Means for Solving the Problems

According to the present invention, there is provided a slip ring device including: a slip ring shaft provided separately from a rotor shaft; a first slip ring and a second slip ring, both of which being put from both ends of the slip ring shaft, respectively, the first slip ring being attached by shrink-fitting to a first slip ring attaching portion of the slip ring shaft, and the second slip ring being attached by shrink-fitting to a second slip ring attaching portion of the slip ring shaft; a lead connecting portion which is located between the first slip ring attaching portion and the second slip ring attaching portion in the slip ring shaft and is formed to be a shaft diameter larger than the shaft diameters of the first slip ring attaching portion and the second slip ring attaching portion of the slip ring shaft; a first radial lead and a second radial lead, the first radial lead being placed in a first radial lead placing hole and the second radial lead being placed in a second radial lead placing hole, the radial lead placing holes being formed in the lead connecting portion; a first axial lead and a second axial lead, both of which being placed in a hollow hole formed in a central portion of the slip ring shaft, the first axial lead being connected to the first radial lead and the second axial lead being connected to the second radial lead; a first slip ring lead which is connected to the first slip ring and to the first radial lead; a second slip ring lead which is connected to the second slip ring and to the second radial lead; and a coupling which is attached by shrink-fitting to a shaft end portion on the rotor shaft side of the slip ring shaft after the first slip ring is attached by shrink-fitting.

Advantageous Effect of the Invention

According to a slip ring device of the present invention, a first slip ring and a second slip ring are put from both ends of a slip ring shaft, respectively, and are attached by shrink-fitting, the slip ring shaft being provided separately from a rotor shaft, the shaft diameter of a lead connecting portion in which a first radial lead and a second radial lead are placed is formed larger than the shaft diameters of respective slip ring attaching portions, and a coupling which is attached by shrink-fitting to a shaft end portion on the rotor shaft side of the slip ring shaft after the first slip ring is attached by shrink-fitting is provided, whereby it becomes possible to obtain the slip ring device which can achieve that time of shrink-fitting work is shortened and strength is improved.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, Embodiment 1 of the present invention will be described with reference toFIG. 1toFIG. 4.FIG. 1is a side sectional view showing a slip ring device and a rotary electric machine using the same according to Embodiment 1 of the present invention.FIG. 2is a relevant part plan view showing the slip ring device according to Embodiment 1 of the present invention.FIG. 3is a relevant part sectional view showing the slip ring device according to Embodiment 1 of the present invention.FIG. 4is a sectional view showing shrink-fitting means for slip rings in the slip ring device according to Embodiment 1 of the present invention.

In these respective drawings, a reference numeral100denotes a slip ring shaft which is provided separately from a rotor shaft51at a position on the outside of the machine, the position having a relatively large shaft diameter such as the position of an oil thrower or the like of a bearing (not shown in the drawing) of the rotor shaft51.100adenotes a first slip ring attaching portion of the slip ring shaft100,100bdenotes a second slip ring attaching portion of the slip ring shaft100,100cdenotes a shaft end portion on the rotor shaft51side of the slip ring shaft100, and100ddenotes a shaft end portion on the side opposite to the rotor shaft51of the slip ring shaft100. Incidentally, the shaft diameter of the shaft end portion100con the rotor shaft51side of the slip ring shaft100is a shaft diameter smaller than the shaft diameter of the first slip ring attaching portion100aof the slip ring shaft100.

101denotes a first slip ring which is put from a shaft end portion100con the rotor shaft51side of the slip ring shaft100and is attached by shrink-fitting to the first slip ring attaching portion100aof the slip ring shaft100, and102denotes a second slip ring which is attached by shrink-fitting to the second slip ring attaching portion100bof the slip ring shaft100.

103denotes a lead connecting portion which is located in the slip ring shaft100between the first slip ring attaching portion100aand the second slip ring attaching portion100bof the slip ring shaft100and is formed larger in shaft diameter than the shaft diameters of the first slip ring attaching portion100aand the second slip ring attaching portion100bof the slip ring shaft100. The outer diameter of the lead connecting portion103is, for example, an outer diameter slightly larger than the outer diameters of the first slip ring101and the second slip ring102.

104denotes a first lead connecting concave portion on the positive pole side, formed in the lead connecting portion103; and105denotes a second lead connecting concave portion on the negative pole side, formed in the lead connecting portion103.

106denotes a first radial lead placing hole formed in the first lead connecting concave portion104of the lead connecting portion103, and107denotes a second radial lead placing hole formed in the second lead connecting concave portion105of the lead connecting portion103.

108denotes a first radial lead to be placed in the first radial lead placing hole106, and109denotes a second radial lead to be placed in the second radial lead placing hole107.

110denotes a hollow hole formed in a central portion of the slip ring shaft100.111and112denote a crescent shaped first axial lead and a crescent shaped second axial lead, both of which being placed in the hollow hole110formed in the central portion of the slip ring shaft100, the first axial lead111being to be connected to the first radial lead108and the second axial lead112being to be connected to the second radial lead109. The first axial lead111and the second axial lead112are connected to a first axial lead61and to a second axial lead62in the rotor shaft51.

Then, an insulator between leads113is inserted between the first axial lead111and the second axial lead112; and an insulator114is inserted between the hollow hole110and the first axial lead111and between the hollow hole110and the second axial lead112. An insulator115is provided at end portions of the first axial lead111and the second axial lead112.

116denotes a first slip ring lead which is connected to the first slip ring101and to the first radial lead108, and117denotes a second slip ring lead which is connected to the second slip ring102and to the second radial lead109.

A first lead communicating concave portion119brought into communication with the first lead connecting concave portion104of the lead connecting portion103is formed in a first slip ring lead supporting portion118which supports the first slip ring lead116. A lead groove120is formed in the first lead communicating concave portion119in the lead connecting portion103and the first slip ring lead116passes through the lead groove120. The lead groove120portion is formed with a wedge groove121and the first slip ring lead116is firmly fixed to the first slip ring lead supporting portion118by a wedge122attached by insertion in the wedge groove121.

Furthermore, a second lead communicating concave portion124brought into communication with the second lead connecting concave portion105of the lead connecting portion103is formed in a second slip ring lead supporting portion123which supports the second slip ring lead117. A lead groove125is formed in the second lead communicating concave portion124in the lead connecting portion103and the second slip ring lead117passes through the lead groove125. The lead groove125portion is formed with a wedge groove126and the second slip ring lead117is firmly fixed to the second slip ring lead supporting portion123by a wedge127attached by insertion in the wedge groove126.

128denotes a coupling which is for attaching the slip ring shaft100to the rotor shaft51and is to be attached by shrink-fitting to the shaft end portion100con the rotor shaft51side of the slip ring shaft100after the first slip ring101is attached by shrink-fitting, and the coupling128is formed smaller in shaft diameter than the shaft diameter of the shaft end portion100con the rotor shaft51side of the slip ring shaft100.

In the slip ring device which is configured such that the coupling128is attached by shrink-fitting to the shaft end portion100con the rotor shaft51of the slip ring shaft100side, the coupling128and the rotor shaft51are integrally joined by a bolt joint, a joint using together bolts and reamer pins, a weld joint or the like to constitute as the rotary electric machine.

Next, an example of a manufacturing process as the slip ring device and a joining process of the coupling128and the rotor shaft51will be described with reference to a flow chart shown inFIG. 5.

First, as shown inFIG. 4, the first slip ring101is put from the shaft end portion100con the rotor shaft51side of the slip ring shaft100which is provided separately from the rotor shaft51, and the first slip ring101is attached by shrink-fitting and fixed to the first slip ring attaching portion100aof the slip ring shaft100. (Step S1)

The second slip ring102is put from the shaft end portion100don the side opposite to the rotor shaft51of the slip ring shaft100and is attached by shrink-fitting and fixed to the second slip ring attaching portion100bof the slip ring shaft100. (Step S2)

Next, the coupling128which is for attaching the slip ring shaft100to the rotor shaft51is attached by shrink-fitting and fixed to the shaft end portion100con the rotor shaft51side of the slip ring shaft100after the first slip ring101is attached by shrink-fitting to the shaft end portion100con the rotor shaft51side of the slip ring shaft100. (Step S3)

The first axial lead111and the second axial lead112, both of which being insulated by the insulator between leads113and the insulator114, are attached by insertion in the hollow hole110of the slip ring shaft100. (Step S4)

Next, the coupling128attached by shrink-fitting and fixed to the shaft end portion100con the rotor shaft51side of the slip ring shaft100is fastened to the rotor shaft51by fastening members to join the slip ring shaft100to the rotor shaft51. (Step S5)

Then, the first radial lead108is connected to the first axial lead111and the second radial lead109is connected to the second axial lead112. (Steps S6, S7)

The first slip ring101is connected to the first radial lead108via the first slip ring lead116. (Step S8)

The first slip ring lead116is fixed to the first slip ring lead supporting portion118by the wedge122. (Step S9)

The second slip ring102is connected to the second radial lead109via the second slip ring lead117. (Step S10)

The second slip ring lead117is fixed to the first slip ring lead supporting portion123by the wedge127. (Step S11)

In this way, the slip ring device is manufactured and the slip ring device is integrally configured with the rotary electric machine by joining of the coupling128and the rotor shaft51.

Furthermore, other example of a manufacturing process as the slip ring device and a joining process of the coupling128and the rotor shaft51will be described with reference to a flow chart shown inFIG. 6.

First, as shown inFIG. 4, the first slip ring101is put from the shaft end portion100con the rotor shaft51side of the slip ring shaft100which is provided separately from the rotor shaft51, and the first slip ring101is attached by shrink-fitting and fixed to the first slip ring attaching portion100aof the slip ring shaft100. (Step S1)

The second slip ring102is put from the shaft end portion100don the side opposite to the rotor shaft51of the slip ring shaft100and is attached by shrink-fitting and fixed to the second slip ring attaching portion100bof the slip ring shaft100. (Step S2)

Next, the coupling128which is for attaching the slip ring shaft100to the rotor shaft51is attached by shrink-fitting and fixed to the shaft end portion100con the rotor shaft51side of the slip ring shaft100after the first slip ring101is attached by shrink-fitting to the shaft end portion100con the rotor shaft51side of the slip ring shaft100. (Step S3)

The first axial lead111and the second axial lead112, both of which being insulated by the insulator between leads113and the insulator114, are attached by insertion in the hollow hole110of the slip ring shaft100. (Step S4)

Next, the first radial lead108is connected to the first axial lead111and the second radial lead109is connected to the second axial lead112. (Steps S15, S16)

The first slip ring101is connected to the first radial lead108via the first slip ring lead116. (Step S17)

The first slip ring lead116is fixed to the first slip ring lead supporting portion118by the wedge122. (Step S18)

The second slip ring102is connected to the second radial lead109via the second slip ring lead117. (Step S19)

The second slip ring lead117is fixed to the first slip ring lead supporting portion123by the wedge127. (Step S20)

Next, the coupling128attached by shrink-fitting and fixed to the shaft end portion100con the rotor shaft51side of the slip ring shaft100is fastened to the rotor shaft51by fastening members to join the slip ring shaft100to the rotor shaft51. (Step S21)

In this way, in a completed state as the slip ring device, the slip ring device is integrally configured with the rotary electric machine by joining of the coupling128and the rotor shaft51. In this case, there is a merit in that the slip ring device can be manufactured as a single body separately from the manufacture of the rotor.

As described above, two manufacturing processes have been described as examples; however, it will be understood that the present invention is not limited thereto, and the flow of the respective steps of the respective manufacturing processes may be slightly shifted if the structure as shown inFIG. 1can be eventually provided.

By the way, an example of joining of the rotor shaft51and the coupling128attached by shrink-fitting and fixed to the shaft end portion100con the rotor shaft51side of the slip ring shaft100will be described.

For example, as exemplarily shown inFIG. 7andFIG. 8, the joining of the coupling128and the rotor shaft51is performed by fastening with bolts129and reamer pins130. As shown inFIG. 7, there is shown an example in which one reamer pin130is disposed at the space between two arranged bolts129.

The coupling128and the rotor shaft51are firmly fastened and joined by the bolts129, and the reamer pins130are attached by insertion by, for example, cooling-fitting at the same radial positions as the bolts129. Incidentally, the positions of the reamer pins130may be provided at different radial positions from the bolts129. Furthermore, the reamer pin130can be substituted by being strongly knocked or by heating the shaft side in place of cooling-fitting.

As described above, high load torque can be transmitted between the coupling128and the rotor shaft51by the shearing force of the reamer pin130in addition of the frictional force of the bolt129.

Furthermore, as exemplarily shown inFIG. 9, a tapered reamer pin131is provided in place of the reamer pin130having a straight shape. In the case of the straight-shaped reamer pin130, the whole length of a reamer portion serves as a fit portion; and therefore, workability is not good in a small space. The tapered reamer pin131is provided; and accordingly, insertion length for cooling-fitting is short and workability is improved.

Furthermore, as exemplarily shown inFIG. 10, a bolt129is formed with a reamer portion129a. A design is made such that the reamer portion129aof the bolt129passes through the interface between the coupling128and the rotor shaft51. The bolt129formed with the reamer portion129ais designed with a clearance in which tolerance is controlled and is clamped by clamping. Alternatively, a design may be designed such that the reamer portion129ais made to an interference fit tolerance, the bolt129formed with the reamer portion129ais fastened in a state where the bolt129is cooled, and the reamer portion129ais fit when returned to ordinary temperature.

In the case where the bolt129formed with the reamer portion129athat is designed with clearance tolerance is used, when the reamer pin130is temporarily deformed by torque or the like during a sudden short-circuit, the reamer pin130is prevented from deforming largely by the shearing force of the reamer portion129aof the bolt129.

In the case where the reamer portion129aof the bolt129is used as interference fit, high torsional torque can be transmitted by the shearing force of the reamer portion129a.

Incidentally, the joining of the coupling128and the rotor shaft51is not limited to the aforementioned joining means; but, it will be understood that the joining thereof may be made by similar configuration or may be made by other joining means.

Furthermore, Ni—Cr—Mo—Va steel is used for the rotor shaft51. Consequently, material having higher strength than the material of the rotor shaft51is used as material of the slip ring shaft100. For example, the slip ring shaft100is made of material in which the content of chemical composition such as Ni is larger than that of the rotor shaft51; and accordingly, the material strength of the slip ring shaft100can be higher than that of the rotor shaft51.

The material having higher strength than that of the rotor shaft51is used for the slip ring shaft100to which high stress is loaded; and accordingly, more reasonable design can be achieved.

By the way, centrifugal force is loaded during operation of the rotary electric machine; and therefore, when the supporting length of the first slip ring lead116and the second slip ring lead117are long, stress generated in the first slip ring lead116and the second slip ring lead117increases.

The first slip ring lead116is fixed to the first slip ring lead supporting portion118by the wedge122and the second slip ring lead117is fixed to the second slip ring lead supporting portion123by the wedge127; and accordingly, each supporting length of the first slip ring lead116and the second slip ring lead117is shortened and thus the stress generated in the first slip ring lead116and the second slip ring lead117can be reduced.

INDUSTRIAL APPLICABILITY

The present invention is suitable for achieving a slip ring device and a rotary electric machine using the same, both of which can achieve that time of shrink-fitting work is shortened and strength is improved.