JP2012244881A - Stator cooling structure for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a cooling medium of a stator from flowing toward a gap between the stator and a rotor in a stator cooling structure for a rotary electric machine.SOLUTION: A rotary electric machine 10 comprises: a stator core 14 including coil ends 16 and 17 in both terminals in an axial direction; and an outer tubular ring 20 which supports the stator core 14 at an inner circumferential side and includes a wall part at the inner circumferential side of both terminal parts 22 further extending axially from both end faces of the stator core 14 in the axial direction as a channel bottom wall part 33 of an annular channel 30 in a coolant flow passage 34 in the case where a cooling medium of a stator flows. A distance from a center axis position C of the outer tubular ring 20 to the channel bottom wall part 33 in a radial direction is defined as a maximum outer diameter of the coolant flow passage 34, the maximum outer diameter of the coolant flow passage 34 is made larger gradually from an upstream side to a downstream side of the coolant flow passage 34 and regarding the coolant flow passage 34, the downstream side is made wider than the upstream side.

Description

  The present invention relates to a stator cooling structure for a rotating electrical machine, and more particularly to a stator cooling structure for a rotating electrical machine that allows a cooling medium to flow in a space surrounded by an outer ring of the rotating electrical machine.

  Since a drive current flows through the coil wound around the stator of the rotating electrical machine, the coil generates heat. Therefore, the stator is cooled.

  Patent Document 1 discloses a configuration in which a slit is provided on the inner peripheral surface of the frame while the frame for fixing the iron core of the stator of the rotating electrical machine is made of metal, although it is not for flowing a cooling medium. Yes.

  In Patent Document 2, as a cooling structure of a rotating electrical machine, an annular jacket through which cooling water flows is formed in a cylindrical housing to which both ends in the axial direction are connected by a front housing and a rear housing, and the inner wall and outer wall of the jacket And a cantilever radiation fin provided on the inner wall of the jacket and directed toward the outer wall, and a configuration in which these fins are arranged in parallel along the circumferential direction of the annular jacket is disclosed. . Here, it is disclosed that the flow passage cross-sectional area of the jacket is narrowed on the upstream side of the coolant by a boss portion into which a bolt for connecting and integrating the housing, the front housing, and the rear housing is integrated. . Thus, it is stated that the heat exchange by the radiating fins is effectively performed by making the flow of the cooling water turbulent.

  In Patent Document 3, in a configuration in which lubricating oil is circulated inside a rotating electrical machine having a rotor in which a permanent magnet is disposed, an inlet passage for the lubricating oil is provided on a support shaft of the rotor, and a radially inner side of the permanent magnet inside the rotor is provided. A passage extending in the axial direction and connected to the outlet on the outside of the rotor is provided, a passage extending in the radial direction connecting the passage and the inlet passage is provided, and the lubricating oil flows into the rotor through these passages. It is disclosed. Here, it is described that a concave-shaped contaminant section is provided in the vicinity of a permanent magnet at a connecting portion between a passage extending in the radial direction inside the rotor and a passage extending in the axial direction. Accordingly, it is stated that contaminants such as iron powder contained in the lubricating oil are collected in the contaminant compartment by the magnetic force of the permanent magnet and the centrifugal force generated by the rotation of the rotor.

  In Patent Document 4, in a vehicle including a power transmission device and an electric motor, when the lubricating oil used in the power transmission device is used for cooling the motor, the lubricating oil circulates inside the power transmission device, so that fine iron powder particles are generated. For example, it is stated that if the iron powder particles enter the coil end of the motor, the insulation quality of the motor may be impaired. Therefore, as a prior art, it is described that a filter and a magnet are provided in an oil reservoir of a power transmission device to remove iron powder particles. Here, it is disclosed that a catch tank including a lubricating oil storage region and a lubricating oil guide region is provided in a casing that houses a power transmission device and an electric motor, and a plurality of magnets are disposed in the catch tank.

JP 2006-340696 A JP-A-8-19218 JP 2007-174755 A JP 2005-83491 A

  In order to cool the stator of the rotating electrical machine, if a cooling medium is allowed to flow inside the case of the rotating electrical machine, foreign matter may be mixed into the cooling medium. Patent Documents 3 and 4 describe that iron powder or the like is mixed when lubricating oil is used as a cooling medium. In addition, foreign matter from the stator may be mixed into the cooling medium. For example, when a split core is used as a stator core, since the mating surfaces of the split core are only in mechanical contact, iron powder foreign matter called sludge is generated and accumulated due to durability deterioration during use. Iron powder foreign matter enters the cooling medium.

  If foreign matter enters the cooling medium flowing inside the rotating electrical machine case, the foreign matter may enter the gap between the stator and the rotor, and may damage the components of the rotating electrical machine. In Patent Document 3, a rotor magnet is used, and in Patent Document 4, it is described that a magnet is disposed in a power transmission mechanism to remove iron powder foreign matter in the cooling medium. The foreign matter cannot be removed before flowing into the gap.

  The objective of this invention is providing the stator cooling structure of the rotary electric machine which can suppress that the flow of the cooling medium of a stator goes to the clearance gap between a stator and a rotor.

  The stator cooling structure for a rotating electrical machine according to the present invention includes a stator having coil ends at both ends in the axial direction, a stator supported on the inner peripheral side, and inner ends of both ends extending in the axial direction further than the axial end surfaces of the stator. An outer cylindrical ring that serves as an outer peripheral side wall in the refrigerant flow channel when the cooling medium of the stator is passed through the peripheral side wall, and from the central axis position of the outer cylindrical ring to the outer peripheral side wall along the radial direction. With the distance as the outer diameter of the refrigerant flow path, the outer diameter of the refrigerant flow path is gradually increased from the upstream side to the downstream side of the refrigerant flow path, and the downstream side of the refrigerant flow path is made wider than the upstream side. Features.

  Further, in the stator cooling structure for a rotating electric machine according to the present invention, the outer cylinder ring has an annular groove provided with a predetermined groove width along the axial direction of both end portions thereof, from the center axis position of the outer cylinder ring. It is preferable to gradually increase the maximum outer diameter of the refrigerant channel from the upstream side to the downstream side of the refrigerant channel with the distance to the groove bottom wall portion along the radial direction as the maximum outer diameter of the refrigerant channel.

  In the stator cooling structure for a rotating electrical machine according to the present invention, it is preferable to have a magnet that is disposed in the annular groove and collects foreign substances contained in the cooling medium.

  With the above configuration, the stator cooling structure of the rotating electrical machine has an outer periphery in the refrigerant flow path when the cooling medium of the stator flows through the inner peripheral wall portions of both end portions that extend in the axial direction further than the axial end surfaces of the stator. An outer cylinder ring as a side wall portion is provided. Then, the outer diameter of the refrigerant channel is gradually increased from the upstream side where the cooling medium of the stator flows toward the downstream side so that the downstream side of the refrigerant channel is wider than the upstream side. In this way, by widening the refrigerant flow path toward the downstream side, the cooling medium is mitigated from colliding with the outer peripheral side wall portion of the refrigerant flow path and rebounding, so that the cooling medium is moved to the inner diameter side coil. It can suppress going to the end side, ie, the clearance gap between a stator and a rotor.

  Further, in the stator cooling structure of the rotating electrical machine, the outer cylinder ring has an annular groove provided with a predetermined groove width along the axial direction of both end portions thereof. Since the distance from the center axis position of the outer ring to the groove bottom wall portion along the radial direction is the maximum outer diameter of the refrigerant flow path, the maximum outside of the refrigerant flow path from the upstream side to the downstream side of the refrigerant flow path. Increase the diameter gradually. In this way, the refrigerant channel can be widened toward the downstream side.

  Further, in the stator cooling structure of the rotating electrical machine, since the magnet is disposed in the annular groove and collects the foreign matter contained in the cooling medium, the foreign matter is removed before the cooling medium moves toward the gap between the stator and the rotor. It can be recovered.

In embodiment which concerns on this invention, it is a figure explaining the content of the stator cooling structure of a rotary electric machine. It is sectional drawing along the AA line of FIG. 1, and is a figure which shows widening the refrigerant | coolant flow path through which the cooling medium flows. It is a figure for demonstrating an effect | action of the stator cooling structure of the rotary electric machine in embodiment which concerns on this invention. As a comparative example, it is a figure for demonstrating the effect | action of the stator cooling structure of the rotary electric machine of a prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Below, the rotary electric machine mounted in a vehicle is demonstrated as a rotary electric machine, However, You may use other than vehicle mounting. In the following description, it is assumed that the lubricating oil used in the power transmission mechanism mounted on the vehicle together with the rotating electrical machine is used as the cooling medium for the stator. However, other cooling media may be used. For example, a circulating cooling medium used only for cooling a rotating electrical machine may be used. In that case, bearing lubricating oil of the rotating electrical machine may be used as a cooling medium, or cooling water or the like may be used. The shape and the like of the annular groove described below are examples, and can be appropriately changed according to the specifications of the rotating electrical machine.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a configuration of a rotating electrical machine 10 having a stator cooling structure. The rotating electrical machine 10 is a rotating electrical machine mounted on a vehicle, and uses a fluid used for lubrication and cooling in a power transmission mechanism mounted on the vehicle as a cooling medium for the stator of the rotating electrical machine 10. As described above, the fluid used for lubrication and cooling in the power transmission mechanism is called ATF (Automatic Transformer Fluid). The right side of FIG. 1 is a sectional view and the left side is a front view. The rotating electrical machine 10 includes a rotor 12, a stator disposed on the outer peripheral side of the rotor 12, and a case for fixing the stator. Here, the stator cooling structure is a structure of a portion including the stator core 14, the outer cylinder ring 20, the refrigerant flow path 34, the magnet 40, and the like. In FIG. 1, in order to mainly explain the stator cooling structure, elements constituting the rotating electrical machine 10 are omitted as follows.

  The rotor 12 is a rotor of the rotating electrical machine 10 that includes an output shaft. In FIG. 1, the rotor 12 is indicated by an imaginary line. The central axis of the output shaft is indicated by CC. In the front view, the position C is the rotation center position of the rotating electrical machine 10. Although the directions of the XYZ axes are shown in FIG. 1, the axial direction of the output shaft is the X-axis direction, and the gravity direction is the Z-axis direction. A front view is a figure which shows a mode seen on the YZ plane.

  The stator includes a stator core 14 and a coil wound around the stator core 14. In FIG. 1, coil portions projecting from both axial ends of the stator core 14 are shown as coil ends 16 and 17.

  The case includes an outer cylinder ring 20 that fixes the outer peripheral side of the stator core 14 and lid portions that close both ends of the outer cylinder ring 20. In FIG. 1, the lid portion is not shown. Therefore, in the front view, the lid is removed and the stator core 14 and the coil end 16 are shown.

  The outer cylinder ring 20 is a cylindrical member and is a member that supports the stator core 14 on the inner peripheral side. The center axis position of the outer ring 20 coincides with the rotation center position of the rotating electrical machine 10 and is a position C.

  The mounting portion 24 that protrudes from the outer peripheral side of the outer cylinder ring 20 is used to fix and attach the rotating electrical machine 10 to the vehicle. The mounting portion 24 is provided with a bolt hole 26. A bolt as a fastening member can be inserted into the bolt hole 26, and the rotating electrical machine 10 can be attached to other components of the vehicle.

  The outer cylinder ring 20 has an axial length longer than the axial length of the stator core 14. In FIG. 1, the long portions are shown as both end portions 22 and 23 extending in the axial direction further than the both end surfaces in the axial direction of the stator core 14.

  A space defined by both end portions 22 and 23 of the outer ring 20, coil ends 16 and 17, and both end surfaces in the axial direction of the stator core 14 is a refrigerant flow path 34 for flowing a cooling medium for the stator. Therefore, the inner peripheral wall portions of the both end portions 22 and 23 are the outer peripheral side wall portions 32 in the refrigerant flow path 34.

  Although not shown, the outer cylinder ring 20 is provided with a cooling medium inlet and a cooling medium outlet. In the front view of FIG. 1, the cooling medium flow 50 flowing into the cooling medium introduction port and the cooling medium flow 52 discharged from the cooling medium discharge port are indicated by white arrows. Thus, the cooling medium flow is provided on the upper side in the Z direction of the outer cylinder ring 20, and the cooling medium discharge port is provided on the lower side in the Z direction of the outer cylinder ring 20. The LL line shown in FIG. 1 is a line indicating the liquid level of the cooling medium stored when the case is closed.

  The cooling medium flow 50 flowing from the cooling medium introduction port of the outer cylinder ring 20 flows downward in the Z direction through the refrigerant flow path 34. And it is stored by the liquid level of the LL line, and is discharged | emitted from the cooling medium discharge port as the cooling medium flow 52 outside. The discharged cooling medium is returned to the power transmission mechanism mounted on the vehicle, heat is removed by an appropriate heat exchanger, and is returned again to the cooling medium inlet using an appropriate circulation pump or the like.

  The annular grooves 30 at both end portions 22 and 23 of the outer cylinder ring 20 are grooves provided in an annular shape along the circumferential direction with a predetermined groove width W along the axial direction of both end portions 22 and 23. The annular groove 30 has a function of expanding the position of the outer peripheral side wall portion 32 in the refrigerant flow path 34 to the outer peripheral side by the groove depth.

In FIG. 1, the distance from the central axis position C of the outer ring 20 to the outer peripheral side wall 32 of the refrigerant flow path 34 along the radial direction is shown as R ₀ . This R ₀ is the outer diameter of the refrigerant flow path 34 when the annular groove 30 is not provided.

  In FIG. 1, the distance from the central axis position C of the outer cylindrical ring 20 to the groove bottom wall portion 33 of the annular groove 30 is indicated as Rθ along the radial direction. This Rθ indicates the outer diameter of the refrigerant flow path 34 widened by the annular groove 30, and this can be called the maximum outer diameter of the refrigerant flow path 34.

  Rθ, which is the maximum outer diameter of the refrigerant flow path 34, is not constant and gradually increases from the upstream side to the downstream side of the refrigerant flow path 34. That is, in the annular groove 30, the maximum outer diameter Rθ of the refrigerant channel 34 is small on the upstream side of the refrigerant channel 34 and large on the downstream side. As a result, the refrigerant flow path 34 is wider on the downstream side than on the upstream side.

  The magnets 40, 42, 43, and 44 provided in the annular groove 30 have a function of collecting foreign matters such as iron powder contained in the cooling medium. The magnets 42 and 43 are provided at the most downstream position of the refrigerant flow path 34. That is, the annular groove 30 is provided on the lowermost side in the Z direction position. The magnets 40 and 44 are provided in the midstream portion of the refrigerant flow path 34. In the example of FIG. 1, the outer cylinder ring 20 is provided at a position corresponding to the position where the mounting portion 24 is disposed.

  FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 2 shows the positional relationship of FIG. 1 rotated 90 degrees. As shown in FIG. 2, the groove bottom wall 33 of the annular groove 30 is located at a distance of Rθ along the radial direction from the central axis position C of the outer cylindrical ring 20. Magnets 40 and 41 are disposed at the groove bottom wall portion 33. Accordingly, the iron powder foreign matter 53 contained in the cooling medium flowing through the annular groove 30 is captured by the magnets 40 and 41 and held at the groove bottom portion of the annular groove 30. Thus, by providing the annular groove 30, the cooling medium can be guided to flow toward the magnets 40 and 41, and the iron powder foreign material 53 can be easily held by the recessed portion of the annular groove 30.

  In the above description, the outer diameter of the refrigerant flow path 34 is enlarged at the annular groove 30, but the groove width W of the annular groove 30 is increased to the axial length of both end portions 22 and 23 of the outer cylinder ring 20. You can spread it. In this case, the outer diameter of the refrigerant flow path 34 gradually increases from the upstream side to the downstream side of the refrigerant flow path 34 over the entire axial length of both end portions 22 and 23.

  The operation of the above configuration will be described with reference to FIG. FIG. 3 is a view corresponding to the front view of FIG. 1, in which the outer peripheral side wall portion 32 of the coolant channel 34 is shown as being the same as the groove bottom wall portion 33 of the annular groove 30. That is, the distance from the central axis position C of the outer ring 20 to the outer peripheral side wall 32 of the refrigerant flow path 34 along the radial direction is Rθ, and Rθ gradually increases from the upstream side to the downstream side of the refrigerant flow path 34. Is set.

In FIG. 3, Rθ at the position of the coolant introduction port through which the coolant flow 50 flows as the most upstream side of the coolant channel 34 is R _0, and the center axis position of the outer ring 20 as the most downstream side of the coolant channel 34. Rθ at a position directly below C is R ₁ . R ₀ is the outer diameter of the original inner peripheral wall portion of the outer ring 20, is the minimum value of Rθ, and R ₁ is the maximum value of Rθ.

  In FIG. 3, the state of the flow 60 of the cooling medium in the refrigerant flow path 34 is indicated by the direction of the thick arrow. Since the refrigerant flow path 34 is gradually widened toward the downstream side, the cooling medium is mitigated from colliding with the outer peripheral side wall 32 of the refrigerant flow path 34 and rebounding. Further, it is possible to suppress the coil end 16 side on the inner diameter side, i.e., toward the gap between the stator and the rotor. Moreover, since the iron powder foreign material 53 contained in the cooling medium is collected by the magnets 40, 42, and 44, it is possible to prevent the iron powder foreign material 53 from damaging the components of the rotating electrical machine 10.

FIG. 4 shows, as a comparison, a case where the distance from the central axis position C of the outer cylinder ring 20 to the outer peripheral side wall 31 of the refrigerant flow path 35 along the radial direction is a constant value of R ₀ and no magnet is provided. It is. Also in FIG. 4, the state of the flow 70 of the cooling medium in the refrigerant flow path 35 is indicated by the direction of the thick arrow. Since the refrigerant flow path 35 has the same size on both the upstream side and the downstream side, the cooling medium often hits the outer peripheral side wall portion 31 of the refrigerant flow path 35 and rebounds. As a result, the cooling medium often goes to the coil end 16 side on the inner diameter side, that is, toward the gap between the stator and the rotor. Since the cooling medium contains iron powder foreign matter or the like, there is a possibility that the components of the rotating electrical machine 10 may be damaged. In addition, since no magnet is provided, it is not possible to recover the iron powder foreign matter contained in the cooling medium.

  The stator cooling structure for a rotating electrical machine according to the present invention can be used for a rotating electrical machine mounted on a vehicle.

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine, 12 Rotor, 14 Stator core, 16, 17 Coil end, 20 Outer ring, 22, 23 Both ends, 24 Mounting part, 26 Bolt hole, 30 Annular groove, 31, 32 Outer peripheral side wall part, 33 Groove bottom wall Part, 34, 35 refrigerant flow path, 40, 41, 42, 43, 44 magnet, 53 iron powder foreign matter.

Claims (3)

A stator having coil ends at both axial ends;
An outer peripheral side wall portion in a refrigerant flow path for supporting a stator on the inner peripheral side and flowing a cooling medium of the stator through inner peripheral wall portions of both end portions extending in the axial direction further than the axial end surfaces of the stator; An outer ring to be
With
The distance from the central axis position of the outer ring to the outer peripheral side wall along the radial direction is defined as the outer diameter of the refrigerant flow path, and the outer diameter of the refrigerant flow path is gradually increased from the upstream side to the downstream side of the refrigerant flow path. A stator cooling structure for a rotating electrical machine, characterized in that the downstream side of the refrigerant flow path is made wider than the upstream side. The stator cooling structure for a rotating electrical machine according to claim 1,
The outer cylinder ring has an annular groove provided with a predetermined groove width along the axial direction of both ends thereof,
The distance from the center axis position of the outer cylinder ring to the groove bottom wall along the radial direction is the maximum outer diameter of the refrigerant flow path, and the maximum outer diameter of the refrigerant flow path from the upstream side to the downstream side of the refrigerant flow path is A stator cooling structure for a rotating electrical machine, characterized by being gradually enlarged. The stator cooling structure for a rotating electrical machine according to claim 2,
A stator cooling structure for a rotating electrical machine, comprising a magnet arranged in an annular groove for collecting foreign matter contained in a cooling medium.

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