Stud mechanism and rotor of rotary electric machine

Abstract

A stud mechanism according to an embodiment of the present invention is applied to a rotor of a rotary electric machine that supplies power by electrically connecting a collector ring (2) on the outer diameter side of a shaft (1) and a conductor (16) on the inner diameter side of the shaft (1) by a collector stud (3) disposed in a through hole passing through the shaft (1). The stud mechanism comprises: a gasket (4) that seals a gap between the collector stud (3) and the through hole of the shaft (1); and screw parts (5, 6, 7, 15) that do not come into contact with the shaft (1) and that fasten the gasket (4) to the inner diameter side of the shaft (1).

Description

Stud mechanism and rotor of rotating electric machine

[0001] An embodiment of the present invention relates to a stud mechanism and a rotor for a rotating electric machine.

[0002] For example, in a rotating electric machine that uses a superconducting wire for the rotor coil, the space inside the shaft that contains the rotor coil is evacuated to prevent heat from entering the low-temperature part of the rotor coil. Also, in some rotating electric machines, the rotor contains a refrigerant gas such as hydrogen inside.

[0003] Power is supplied to the rotor coil via a collector ring on the outer diameter side of the shaft and a collector stud that connects a conductor on the inner diameter side of the shaft that is connected to the rotor coil.

[0004] The shaft has a shaft through-hole for the collector stud to pass through, and there is a gap between this shaft through-hole and the collector stud placed in that shaft through-hole. This gap is closed (sealed) by a gasket to maintain the internal vacuum or refrigerant. To ensure sufficient sealing performance, the gasket is compressed with an appropriate amount of axial force by the gasket retaining nut. Furthermore, during operation, the collector stud may deform due to thermal expansion or centrifugal force, which could cause poor contact or damage to the current-carrying parts. To prevent this, the collector stud is secured in place with a stud retaining nut.

[0005] FIG. 5 shows an example of the configuration of a general stud mechanism centered around a collector stud.

[0006] A collector ring 2 on the outside of the shaft 1 receives power from a fixed brush. A collector stud 3 is connected to the collector ring 2, and this collector stud 3 passes through a shaft through-hole that penetrates the inside and outside of the shaft 1 and is connected to a center hole copper band 16 in a vacuum or refrigerant with a screw at the inner diameter side end, electrically connecting the collector ring 2 and the center hole copper band 16. An insulating tube 13 is inserted between the center hole copper band 16 and the shaft 1. An insulating cap 14 is inserted into the outer diameter side opening of the shaft through-hole as needed.

[0007] Gasket 4 seals the gap between collector stud 3 and the shaft through-hole of shaft 1. This gasket 4 is compressed to the compression ratio required for sealing the vacuum or refrigerant by the axial force of gasket retaining nut 6. A washer 5 for transmitting the force evenly and a disc spring 15 for preventing loosening of gasket retaining nut 6 are inserted between gasket 4 and gasket retaining nut 6 as needed.

[0008] The collector stud 3 is subjected to thermal expansion and centrifugal force during operation, but is fixed in place by the axial force of the stud retaining nut 7 .

[0009] A contact nut 8 is attached to the threaded portion on the outer diameter end of the collector stud 3 and is pressed against the stud retaining nut 7 by axial force. The contact nut 8 is adjusted by a copper shim 9 inserted at the top or bottom so that it will come into contact with the connecting copper strip 10 when it is attached to the collector ring 2. After the connecting copper strip 10 is attached to the collector ring 2 by bolting or the like, a contact nut 11 is attached to the threaded portion on the outer diameter end of the collector stud 3, and the connecting copper strip 10 is sandwiched together with the contact nut 8. This forms a conductive path from the collector ring 2 to the collector stud 3. All of the parts involved in this conductive path, except for the collector ring 2, are made of copper-based materials with high electrical conductivity.

[0010] In the stud mechanism of the conventional rotating electrical machine described above, the threaded portion for tightening the gasket retaining nut 6 is provided in the shaft through-hole of the shaft 1. However, when an Mg alloy or the like is used as the shaft material to reduce weight, the strength of the threaded portion is insufficient, and the retaining nut 6 cannot be tightened to the required axial force. In addition, because the gasket 4 and the gasket retaining nut 6 are located deep in the shaft through-hole, assembly and disassembly are difficult in small aircraft.

[0011] For these reasons, it is desirable to provide a stud mechanism and a rotor for a rotating electrical machine that can easily achieve a reduction in shaft weight and improved workability.

[0012] The stud mechanism of this embodiment is a stud mechanism applied to the rotor of a rotating electric machine in which a collector ring on the outer diameter side of a shaft and a conductor on the inner diameter side of the shaft are electrically connected by a collector stud placed in a through hole that passes through the shaft to supply power, and is equipped with a gasket that fills the gap between the collector stud and the through hole of the shaft, and a threaded portion that does not come into contact with the shaft and tightens the gasket to the inner diameter side of the shaft.

[0013] Fig. 1 is a diagram showing an example of the configuration of a rotating electrical machine having a stud mechanism according to first to third embodiments. Fig. 2 is a diagram showing an example of the configuration of the stud mechanism according to the first embodiment. Fig. 3 is a diagram showing an example of the configuration of the stud mechanism according to the second embodiment. Fig. 4 is a diagram showing an example of the configuration of the stud mechanism according to the third embodiment. Fig. 5 is a diagram showing an example of the configuration of a general stud mechanism. Embodiment

[0014] Hereinafter, embodiments will be described with reference to the drawings.

[0015] First Embodiment First, the first embodiment will be described.

[0016] Fig. 1 is a diagram showing an example of the configuration of a rotating electric machine having a stud mechanism according to a first embodiment. Here, the configuration of the rotor of the rotating electric machine will be mainly described. Note that the configuration of Fig. 1 is also applicable to second and third embodiments described later.

[0017] The rotating electric machine shown in Fig. 1 is a superconducting rotating electric machine, and includes a shaft 1 supported by bearings 100, a collector ring 2 supplied with power from brushes 101, a collector stud 3 electrically connected to the collector ring 2, a center-hole copper band 16 electrically connected to the collector stud 3, and a connecting copper plate 102 electrically connected to the center-hole copper band 16. A vacuum vessel provided in a part of the shaft 1 contains a rotor coil 103 electrically connected to the connecting copper plate 102. An insulating cylinder 12 is provided between the collector ring and the shaft 1. An insulating cylinder 13 is provided between the center-hole copper band 16 and the shaft 1.

[0018] 2 shows an example of the configuration of the stud mechanism according to the first embodiment, which illustrates the cross-sectional shapes of the AA cross sections shown at two points in FIG.

[0019] Figure 2 shows a shaft 1, a collector ring 2, a collector stud 3, a gasket 4, a washer 5, a gasket retaining nut 6, a stud retaining nut 7, a contact nut 8, a copper shim 9, a connecting copper strip 10, a contact nut 11, an insulating tube 12, an insulating tube 13, an insulating cap 14, a disc spring 15, and a center hole copper strip (conductor) 16.

[0020] In this embodiment, the shaft 1 is made of an Mg alloy to reduce the weight of the rotating electrical machine.

[0021] The outside of the shaft 1 is air, and the inside is a vacuum or refrigerant gas. The collector ring 2 is attached to the outside of the shaft 1 via an insulating tube 12. This collector ring 2 receives power from the fixed brush. A collector stud 3 is connected to the collector ring 2, and this collector stud 3 passes through a shaft through-hole that penetrates the inside and outside of the shaft 1 and is connected to a center hole copper band 16 in the vacuum or refrigerant with a screw at the inner diameter side end, thereby electrically connecting the collector ring 2 and the center hole copper band 16.

[0022] Insulation is wrapped around the collector stud 3 in the section where it is close to the shaft 1. An insulating tube 13 is inserted between the central hole copper band 16 and the shaft 1. If necessary, an insulating cap 14 is inserted into the outer diameter opening of the shaft through-hole. With these measures, the shaft 1 is completely insulated from the current-carrying parts.

[0023] The gap between the collector stud 3 and the shaft through-hole of the shaft 1 is sealed by a gasket 4 to maintain the vacuum or refrigerant inside the shaft 1. This gasket 4 is compressed to the compression ratio required to seal the vacuum or refrigerant by the axial force of a gasket retaining nut 6 that is tightened with a screw. A washer 5 to transmit the force evenly and a disc spring 15 to prevent the gasket retaining nut 6 from loosening are inserted between the gasket 4 and the gasket retaining nut 6 as needed.

[0024] The collector stud 3 is subjected to thermal expansion and centrifugal force during operation, but is fixed in place by the axial force of the stud retaining nut 7 .

[0025] The threaded portions of the gasket retaining nut 6 and the stud retaining nut 7 are subjected to a large load, so these parts are made of high-strength materials such as iron.

[0026] A contact nut 8 is attached to the threaded portion on the outer diameter end of the collector stud 3 and is pressed against the stud retaining nut 7 by axial force. The contact nut 8 is adjusted by a copper shim 9 inserted at the top or bottom so that it will come into contact with the connecting copper strip 10 when it is attached to the collector ring 2. After the connecting copper strip 10 is attached to the collector ring 2 by bolting or the like, a contact nut 11 is attached to the threaded portion on the outer diameter end of the collector stud 3, and the connecting copper strip 10 is sandwiched together with the contact nut 8. This forms a conductive path from the collector ring 2 to the collector stud 3. All of the parts involved in this conductive path, except for the collector ring 2, are made of copper-based materials with high electrical conductivity.

[0027] The above structure is constructed so that there are no parts where iron and copper parts are joined with screws.

[0028] In this embodiment, the threaded portions that fasten the gasket 4 to the inner diameter side of the shaft 1, specifically the washer 5, gasket retaining nut 6, stud retaining nut 7, disc spring 15, etc., are provided on the collector ring 2 made of a high-strength iron-based material and are configured so as not to come into contact with the shaft 1.

[0029] The gasket 4 is provided near the outer diameter side opening of the through hole of the shaft 1, and the gasket retaining nut 6 is provided in the through hole of the collector ring 2 and is configured to tighten the gasket 4 via a washer 5 and a disc spring 15. Specifically, the gasket retaining nut 6 rotates along the threads cut in the through hole of the collector ring 2, tightening the gasket 4 against the inner diameter side of the shaft 1.

[0030] Because of this configuration, according to the first embodiment, when an Mg alloy or the like is used for the shaft 1 to reduce weight, the problem of not being able to tighten the retaining nut 6 until the required axial force is generated does not occur. Furthermore, because the gasket 4 and the gasket retaining nut 6 are not located deep in the shaft through-hole, the problem of assembly and disassembly being difficult in a small aircraft does not occur.

[0031] Second Embodiment Next, a second embodiment will be described, focusing on differences from the first embodiment.

[0032] The configuration of the rotating electrical machine having the stud mechanism according to the second embodiment is similar to that shown in FIG.

[0033] 3 shows an example of the configuration of a stud mechanism according to the second embodiment, which is a modified example of the configuration shown in FIG.

[0034] In the configuration of the first embodiment, there may be cases where space does not allow for the provision of a threaded portion on the collector ring 2 for attaching the stud retaining nut 7. In such cases, as shown in Figure 3, the stud retaining nut 7 is positioned so that it contacts the inner diameter side of the gasket retaining nut 6. The stud retaining nut 7 is then configured to rotate along the threads on the inner diameter side of the gasket retaining nut 6, tightening the collector stud 3 against the inner diameter side of the shaft 1.

[0035] With this configuration, according to the second embodiment, it is possible to further reduce the size of the rotating electrical machine.

[0036] Third Embodiment Next, a third embodiment will be described, focusing on differences from the second embodiment.

[0037] The configuration of the rotating electrical machine having the stud mechanism according to the third embodiment is similar to that shown in FIG.

[0038] 4 shows an example of the configuration of a stud mechanism according to the third embodiment, which is a modified example of the configuration shown in FIG.

[0039] In the third embodiment, the gasket retaining nut 6 shown in the second embodiment is combined with the stud retaining nut 7 to form a common retaining nut 6a, which uses a single nut to hold down the thermal expansion and centrifugal force of the gasket 4 and collector stud 3. Specifically, the common retaining nut 6a rotates along the threads cut into the through hole of the collector ring 2, and in addition to tightening the gasket 4 against the inner diameter side of the shaft 1, it also tightens the collector stud 3 against the inner diameter side of the shaft 1.

[0040] With this configuration, according to the third embodiment, it is possible to realize a rotating electric machine that is easy to manufacture while reducing the number of parts.

[0041] As described above in detail, according to the embodiment, it is possible to easily achieve a lighter shaft and improved workability.

[0042] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. A stud mechanism applied to the rotor of a rotating electric machine in which a collector ring on the outer diameter side of a shaft and a conductor on the inner diameter side of the shaft are electrically connected by a collector stud placed in a through hole that passes through the shaft to supply power, the stud mechanism comprising: a gasket that fills the gap between the collector stud and the through hole of the shaft; and a threaded portion that does not come into contact with the shaft and tightens the gasket to the inner diameter side of the shaft.

2. A stud mechanism according to claim 1, wherein the threaded portion includes a gasket retaining nut, and the gasket retaining nut rotates along threads cut into the through hole of the collector ring to tighten the gasket against the inner diameter side of the shaft.

3. The stud mechanism according to claim 2, wherein the threaded portion further includes a stud retaining nut, and the stud retaining nut rotates along threads cut into the through hole of the collector ring to tighten the collector stud against the inner diameter side of the shaft.

4. The stud mechanism according to claim 2, wherein the threaded portion further includes a stud retaining nut that contacts the gasket retaining nut, and the stud retaining nut rotates along threads cut into the inner diameter side of the gasket retaining nut to tighten the collector stud against the inner diameter side of the shaft.

5. The stud mechanism according to claim 2, wherein the gasket retaining nut rotates along threads cut into the through hole of the collector ring to tighten the gasket against the inner diameter side of the shaft and also tighten the collector stud against the inner diameter side of the shaft.

6. A stud mechanism according to any one of claims 1 to 5, wherein the shaft is made of an Mg alloy.

7. A rotor for a rotating electrical machine, comprising the stud mechanism according to any one of claims 1 to 5.

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