JP2017017940A - Slip ring mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slip ring mechanism in which floating of a brush from a slip ring is prevented.SOLUTION: A cooling medium supplied onto an outer surface 11b of a slip ring 11 flows into an area between a brush 12 and the slip ring 11, as the slip ring 11 rotates. While the cooling medium is cooling a sliding surface between the brush 12 and the slip ring 11, part of the medium flows through a through-hole 21 and flows into a substantially columnar in-shaft passage 10 inside a rotary shaft 4. As the cooling medium flows through the through-hole 21, the brush 12 is attracted to the slip ring 11. As a result, floating of the brush 12 from the slip ring 11 can be prevented even if the cooling medium flows onto the sliding surface between the brush 12 and the slip ring 11.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a slip ring mechanism for supplying electric power to a rotor of a rotating electrical machine.

  A rotating electrical machine such as a motor generally includes a stator fixed to a casing, a rotor that can rotate relative to the stator, and a slip ring mechanism that supplies electric power to the rotor. The slip ring mechanism is usually composed of a plurality of poles. Each pole has a slip ring provided on the outer periphery of the rotating shaft, a brush provided to be pressed against the slip ring, and a brush holder for fixing the brush. It consists of and. Since power is supplied to the slip ring via the brush or friction between the brush and the slip ring generates heat, the slip ring and the brush generate heat, so that it is necessary to cool each pole. In the slip ring mechanism described in Patent Document 1, the slip ring and the brush are accommodated in the accommodation chamber in which the fluorine-based liquid is enclosed in order to suppress the scattering of the abrasion powder and improve the cooling efficiency of the slip ring and the brush. Yes.

JP 2013-183559 A

  However, in the slip ring mechanism described in Patent Document 1, a liquid film is easily generated between the brush and the slip ring. When a liquid film is generated between the brush and the slip ring, the brush floats with respect to the slip ring due to the liquid film pressure, and the contact between the brush and the slip ring is lost. If it does so, arc discharge will generate | occur | produce between a brush and a slip ring, and the abrasion of a brush will be accelerated | stimulated, and there existed a problem that control of a rotary electric machine became difficult because the electric current which flows through a slip ring became a consequent.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a slip ring mechanism that prevents the brush from floating with respect to the slip ring.

A slip ring mechanism according to the present invention includes at least one slip ring that rotates integrally with a rotation shaft, and a brush that slides relative to the slip ring, the rotation shaft formed in a hollow structure, An internal shaft passage is provided, and the slip ring has an opening on the outer surface of the slip ring with which the brush contacts, and a through hole that communicates with the internal shaft passage and opens on the inner surface of the rotation shaft. The end is provided with a discharge port for discharging the cooling medium introduced into the in-shaft passage through the through-hole to the outside of the rotating shaft, and the through-hole is formed in the in-shaft passage by rotating the rotating shaft. And a fin for introducing the cooling medium into the in-shaft passage and discharging the cooling medium toward the discharge port.
The slip ring may be exposed to the in-axis passage and may constitute a part of the in-axis passage.
The slip ring may be entirely exposed to the in-axis passage and may constitute a part of the in-axis passage, and fins may be provided in portions other than the in-axis passage formed by the slip ring in the in-axis passage.
The rotating shaft is provided with a second through hole that opens on the outer surface of the rotating shaft and opens on the inner surface of the rotating shaft and communicates with the in-shaft passage in a portion other than the slip ring. The inner diameter may be larger than the inner diameter of the through hole.
A reinforcing member extending in the axial direction of the rotation shaft may be provided between the fin and the rotation shaft.

  According to this invention, the cooling medium between the brush and the slip ring passes through the through-hole by providing the slip ring with a through-hole that opens on the outer surface in contact with the brush and opens on the inner surface of the rotating shaft. Since the brush flows into the inside of the rotating shaft and is thereby attracted to the slip ring, it is possible to prevent the brush from floating with respect to the slip ring.

It is sectional drawing of the slip ring mechanism which concerns on embodiment of this invention. It is sectional drawing of a pair of brush and slip ring in the slip ring mechanism which concerns on this embodiment. It is sectional drawing of the modification of the slip ring mechanism which concerns on embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIG. 1, the slip ring mechanism 1 is provided on a bracket 2 of a rotor (not shown). The bracket 2 includes a substantially columnar structure 3 and a cylindrical rotation shaft 4. The slip ring mechanism 1 includes three ring-shaped slip rings 11 provided so as to be rotatable integrally with the rotary shaft 4 and brushes 12 provided so as to be in contact with the slip rings 11.

  The inner surface 4a of the rotating shaft 4 is provided with resin-made spiral fins 14a formed on the inner surface of a substantially cylindrical base portion 14b made of resin. The fin 14a is not provided on the entire inner surface 4a, but is formed on a portion other than the portion where the window portion 13 partially opened on the base portion 14b is formed. The inner surface 4a is exposed from the window portion 13. A part of the inner surface 11 a of the slip ring 11 is exposed from a part of the inner surface 4 a exposed from the window portion 13. The exposed inner surface 11 a constitutes a part of the inner surface 4 a of the rotating shaft 4. One end of the base portion 14 b is fixed to the structure 3, and the other end is located in the discharge port 4 c opened at the end of the rotating shaft 4.

  The slip ring 11 is formed with a plurality of through-holes 21 opened on the inner surface 11a and the outer surface 11b. In the rotating shaft 4, second through holes 22 are formed in the vicinity of the connecting portion between the structure 3 and the rotating shaft 4 and open to the inner surface 4 a and the outer surface 4 b of the rotating shaft 4. The inner diameter of the second through hole 22 is larger than the inner diameter of the through hole 21. In this embodiment, the number of second through holes 22 is one, but a plurality of second through holes 22 may be provided. Further, the position to be provided may be anywhere as long as it is a portion other than the slip ring 11.

Next, the operation of the slip ring mechanism 1 according to the embodiment of the present invention will be described.
When a rotor (not shown) rotates, the bracket 2 also rotates together with the rotor, and as a result, the rotating shaft 4 also rotates. When the rotating shaft 4 rotates, the slip ring 11 also rotates. However, since the brush 12 does not rotate together with the rotating shaft 4, the brush 12 slides with respect to the slip ring 11, that is, the brush 12 and the slip ring 11 come into contact with each other. However, only the slip ring 11 rotates. Then, frictional heat is generated on the sliding surface between the brush 12 and the slip ring 11, and the temperature of the brush 12 and the slip ring 11 is raised. Therefore, a cooling medium such as oil is supplied onto the outer surface 11 b of the slip ring 11 in order to cool the brush 12 and the slip ring 11.

  As shown in FIG. 2, the cooling medium supplied on the outer surface 11 b of the slip ring 11 flows between the brush 12 and the slip ring 11 as the slip ring 11 rotates. While the cooling medium cools the sliding surface between the brush 12 and the slip ring 11, a part of the cooling medium passes through the through hole 21 and flows into the substantially cylindrical in-axis passage 10 inside the rotating shaft 4. Since the brush 12 is attracted to the slip ring 11 as the cooling medium flows through the through-hole 21, the brush against the slip ring 11 even if the cooling medium flows into the sliding surface between the brush 12 and the slip ring 11. 12 can be prevented from floating.

  However, when the inner diameter of the through hole 21 is small, the cooling medium may stay in the through hole 21 and may not flow into the shaft passage 10. In this case, the brush 12 may float with respect to the slip ring 11. However, in this embodiment, as shown in FIG. 1, since the spiral fin 14a is provided on the inner surface 4a of the rotating shaft 4, it flows out of the opening of the inner surface 4a through the through hole 21. The cooling medium moves toward the discharge port 4 c along the fins 14 a as the rotating shaft 4 rotates. Thereby, it is promoted that the cooling medium flows through the through-hole 21, and the retention of the cooling medium in the through-hole 21 is prevented. The cooling medium reaching the discharge port 4c is discharged from the in-shaft passage 10 through the discharge port 4c.

  In order to obtain the same effect as that provided by the fin 14a, a device for sucking the cooling medium in the in-shaft passage 10 from the outside of the rotating shaft 4 through the discharge port 4c can be provided. In this case, the slip ring mechanism becomes larger by the amount of the device. On the other hand, in the slip ring mechanism 1 according to the present embodiment, the slip ring mechanism 1 becomes compact by providing the fins 14 a inside the rotating shaft 4.

  Further, when the rotor (not shown) rotates, the cooling medium flows into the in-shaft passage 10 through the second through hole 22. The cooling medium that has flowed into the in-shaft passage 10 through the second through-hole 22 also moves toward the discharge port 4c on the same principle, but is exposed to the in-shaft passage 10 through the window portion 13. To touch. Since the slip ring 11 is cooled by this contact, cooling of the slip ring 11 is promoted.

  In this way, the slip ring 11 is provided with the through-hole 21 that opens to the outer surface 11 b in contact with the brush 12 and opens to the inner surface 4 a of the rotating shaft 4, thereby cooling the cooling medium between the brush 12 and the slip ring 11. Flows into the inside of the rotary shaft 4 through the through-hole 21, whereby the brush 12 is attracted to the slip ring 11, so that the brush 12 can be prevented from floating with respect to the slip ring 11.

  In this embodiment, three slip rings 11 are provided, but the number is not limited to three. Only one may be provided, or two or four or more may be provided. However, no matter how many slip rings 11 are provided, each slip ring is provided with a brush in contact therewith.

  In this embodiment, a part of the slip ring 11 is exposed from the inner surface 4 a to constitute a part of the inner surface 4 a of the rotating shaft 4, that is, a part of the slip ring 11 is exposed to the in-axis passage 10. However, the present invention is not limited to this configuration. All of the inner surface 11a of the slip ring 11 may be exposed from the inner surface 4a. In this case, the fins 14 a formed on the inner surface of the base portion 14 b are provided only between the adjacent slip rings 11 and 11. However, when only one slip ring 11 is provided, fins 14a are provided at portions other than the slip ring 11. Thereby, cooling of the slip ring 11 is further promoted. Moreover, although the cooling efficiency of the slip ring 11 falls, the slip ring 11 does not need to be exposed from the inner surface 4a. However, in this case, the through-hole 21 further extends from the opening of the inner surface 11a of the slip ring 11 to the inner surface of the rotary shaft 4 so that the cooling medium flowing through the through-hole 21 can flow into the shaft passage 10. It is necessary to have a configuration that extends toward 4a and opens at the inner surface 4a.

  In this embodiment, the fins 14a and the base portion 14b are made of resin, but may be made of metal as long as insulation between the slip rings 11 can be secured. Further, in order to reinforce the strength of the fins 14a and the base portion 14b, a metal reinforcing member 30 may be provided so as to be embedded in the base portion 14b as shown in FIG. The reinforcing member 30 is provided so that one end is fixed to the structure 3 and the other end protrudes from the end of the base portion 14b. However, the other end may be terminated at the end of the base portion 14b, or may be terminated at the structure 3 side from the end of the base portion 14b. Further, the reinforcing member 30 is not limited to a form embedded in the base portion 14b, and may be provided between the fin 14a and the base portion 14b, as long as insulation between the slip rings 11 can be secured. The base portion 14b and the inner surface 4a may be provided. That is, the reinforcing member 30 may be provided between the fin 14 a and the rotating shaft 4.

  In this embodiment, the fins 14a are provided in a spiral shape, but the present invention is not limited to this form. If the fin 14a is provided to be inclined toward the discharge port 4c, the cooling medium can move toward the discharge port 4c along the fin 14a as the rotating shaft 4 rotates.

  In this embodiment, the cooling medium is supplied onto the outer surface 11b of the slip ring 11, but this is not a limitation. Similar to the invention described in Patent Document 1, the slip ring 11 and the brush 12 may be located in the cooling medium.

  1 Slip ring mechanism, 4 Rotating shaft, 4a (Rotating shaft) inner surface, 4b (Rotating shaft) outer surface, 4c Discharge port, 10 Shaft passage, 11 Slip ring, 11a (Slip ring) inner surface, 11b Outer surface (of slip ring), 12 brush, 14a fin, 21 through hole, 22 second through hole, 30 reinforcing member.

Claims (5)

At least one slip ring that rotates integrally with the rotating shaft;
A brush that slides against the slip ring,
The rotating shaft is formed in a hollow structure,
An in-shaft passage is provided inside the rotating shaft,
The slip ring is provided with a through-hole that opens to the outer surface of the slip ring that contacts the brush and opens to the inner surface of the rotating shaft and communicates with the in-axis passage.
A discharge port for discharging the cooling medium introduced into the in-shaft passage through the through hole to the outside of the rotation shaft is provided at the end of the rotation shaft,
The shaft passage is provided with a fin for introducing the cooling medium into the shaft passage through the through hole and discharging the cooling medium toward the discharge port as the rotating shaft rotates. Slip ring mechanism.   The slip ring mechanism according to claim 1, wherein the slip ring is exposed to the in-axis passage and constitutes a part of the in-axis passage. The slip ring is entirely exposed in the in-axis passage and constitutes a part of the in-axis passage,
The slip ring mechanism according to claim 2, wherein the fin is provided in a portion of the in-axis passage other than the in-axis passage formed by the slip ring.   The rotating shaft is provided with a second through-hole that opens on the outer surface of the rotating shaft and opens on the inner surface of the rotating shaft and communicates with the passage in the shaft, in a portion other than the slip ring, The slip ring mechanism according to any one of claims 1 to 3, wherein an inner diameter of the second through hole is larger than an inner diameter of the through hole.   The slip ring mechanism according to any one of claims 1 to 4, wherein a reinforcing member extending in an axial direction of the rotation shaft is provided between the fin and the rotation shaft.

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