WO2015098328A1

WO2015098328A1 - Rotating electric machine

Info

Publication number: WO2015098328A1
Application number: PCT/JP2014/079909
Authority: WO
Inventors: 山崎　慎司; 本間　雅彦; 清水　尚也
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2013-12-27
Filing date: 2014-11-12
Publication date: 2015-07-02
Also published as: JPWO2015098328A1; JP6314158B2

Abstract

Provided is a rotating electric machine having both high cooling efficiency and low pressure loss. This rotating electric machine is configured so as to have: a stator; a rotor rotatably held within the stator with a prescribed gap therebetween; and a cooling liquid passage (15) located at the outer periphery of the stator and formed within a housing. The cooling liquid path comprises a cooling liquid inlet (111) provided at one end of the cooling liquid path, a cooling liquid outlet (112) provided at the other end, circumferential passages (151, 152, 153) arranged in multiple rows in the axial direction, orthogonal to the circumferential direction; and an oblique passage (161) connecting the circumferential passages in the axial direction. The circumferential passages and the oblique passage are connected such that the direction of flow of the cooling liquid in each circumferential passage is the same in the circumferential direction.

Description

Rotating electric machine

The present invention relates to a rotating electrical machine.

Electric / electronic devices used in automobiles are required to be smaller and have higher output. In rotating electrical machines, the heat generated in the stator conductor is cooled by increasing the amount of current, so forced cooling with coolant or oil is required. Is becoming indispensable.

As a water-cooled rotating electrical machine, there is known one in which a belt-shaped coolant passage and a boundary wall of the coolant passage are provided in a housing that holds a stator, and the coolant flows in the circumferential direction (for example, Patent Documents). 1).

Further, in order to effectively cool the stator, there is known one in which a boundary wall made of another member is inserted in the coolant passage (for example, see Patent Document 2).

JP 2009-247085 A JP 2004-364429 A

However, in the prior art as described above, stagnation occurs due to the flow of the liquid, and the cooling efficiency of the stagnation portion decreases. In addition, in the case where the cooling fluid passage structure is complicated in order to avoid stagnation, it is difficult to keep the pressure loss in the cooling fluid passage low. When the pressure loss is high, it is necessary to increase the output of the pump for circulating the coolant, and the efficiency of the entire vehicle is reduced. The prior art has not fully considered these problems.

Therefore, an object of the present invention is to provide a cooling structure for a rotating electric machine that achieves both high cooling efficiency and low pressure loss.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, a stator, a rotor that is rotatably held inside the stator via a predetermined gap, and the fixed A coolant passage formed in the housing, the coolant passage having a coolant introduction port provided at one end, and a coolant discharge port provided at the other end. A plurality of axially arranged circumferential passages that are perpendicular to the circumferential direction, and oblique passages that connect the circumferential passages in the axial direction, and the flow of the coolant in the circumferential passages. The circumferential passage and the skew passage are connected so that the direction is the same as the circumferential direction.

According to the present invention, it is possible to provide a rotating electrical machine that achieves both high cooling efficiency and low pressure loss. Problems, configurations, and effects other than those described above will become apparent from the description of the following examples.

1 is a side sectional view showing Example 1. FIG. FIG. 3 is a top view showing a coolant passage inside the center bracket of the first embodiment. FIG. 3 is a perspective view illustrating a coolant passage shape according to the first embodiment. The perspective view which shows the coolant channel shape at the time of reducing the number of stages of a coolant channel. The perspective view which shows the coolant channel shape at the time of increasing the number of stages of a coolant channel. FIG. 3 is a conceptual diagram illustrating a mold structure for forming a coolant passage according to the first embodiment. FIG. 3 is a side cross-sectional view showing an example in which the type of the stator of Example 1 is changed. FIG. 6 is a side sectional view showing Example 2. FIG. 6 is a perspective view showing the shape of an inner housing of Example 2. The sectional side view which shows the example which changed the kind of stator of Example 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the following description, a rotating electrical machine used for an electric vehicle is used as an example. This rotating electric machine has a function of a motor that drives wheels of a vehicle and a function of a generator that generates electric power using regeneration, and these functions are used by switching according to the traveling state of the vehicle. .

Embodiments according to the present invention will be described with reference to FIGS.

It has a substantially cylindrical center housing 11 and a front housing 12 and a rear housing 13 that close the opening. The center housing 11 has a stator 3 that is fixed by shrink fitting or press fitting, and a rotor 4 that is rotatably held inside the center housing 11. The stator 3 is formed by winding a stator coil 32 around a plurality of slots provided in a stator core 31 formed by laminating electromagnetic steel plates.

In the rotor 4, a rotor core 41 formed by laminating electromagnetic steel plates is fastened with a shaft 44 by shrink fitting or press fitting, and the shaft 44 is rotatable via a bearing 5 provided in the rear housing 11 and the front housing 12. Power is transmitted from a portion that is held and protrudes from the front housing 12.

The rotating electrical machine having the above configuration is installed in an engine room of a vehicle (not shown), and transmits a driving force via a spline or the like provided at the tip of the shaft 44. In addition, it is connected to a control device (not shown) such as an inverter with a three-phase power cable to control drive and power generation.

A coolant introduction port 111 and a coolant discharge port 112 are provided on the outer periphery of the center housing 11. The center housing 11 is sandwiched between the rear housing 11 and the front housing 12 at the end in the axial direction, and is fixed by bolts or the like. The coolant passage 15 formed integrally with the center housing 11 is formed in a belt shape on the outer periphery of the stator 3.

The coolant passage 15 includes

circumferential passages

151, 152, and 153 that are arranged in three stages in the axial direction, and

skew passages

161 and 162 that connect the circumferential passages in series. The upstream end of the circumferential passage 151 is connected to the coolant introduction port 111, and the downstream end is connected to the skew passage 161. Subsequently, a series of coolant passages 15 is configured by continuously connecting to the skew passage 161, the middle circumferential passage 152, the skew passage 162, the circumferential passage 153, and the coolant discharge port 112. . The oblique passages connecting the circumferential passages are not folded back, and the flow direction of the circumferential passages is the same in each stage, so that there is no stagnation and an increase in pressure loss can be suppressed.

The

circumferential passages

151, 152, and 153 are provided so as to extend in the circumferential direction, that is, to extend in the circumferential direction on a plane orthogonal to the rotation axis of the rotor. In addition, as long as it is within a range that functions as a coolant passage, it is not necessary to be disposed on a plane strictly perpendicular to the rotation axis of the rotor, and it is not necessary to be strictly disposed in a circumferential shape.

In order to suppress an increase in pressure loss, the width of the oblique passage 161 is preferably the same as that of the circumferential passage 151, and the angle θ formed by the

circumferential passages

151, 152 and the

oblique passages

161, 162 is preferably small. In this embodiment, the coolant introduction port 111 and the coolant discharge port 112 are arranged on different axes in the rotation axis direction, so that the coolant introduction port 111 and the coolant discharge port are compared with the case where they are arranged on the same axis. By increasing the distance to 112, a region for arranging the skew passage is secured, and the shape in which the pressure loss of the coolant passage 15 is suppressed by adjusting the skew passage width and angle θ is realized. As shown in FIGS. 4 and 5, adjustment is possible by changing the width and the number of steps of the coolant passage according to the coolant flow rate and the length of the center housing 11 and the stator 3.

The coolant passage 15 is integrally formed with a collapsible core made of sand or resin when the center housing 11 is produced by casting such as die casting. Since the collapsible core is formed by a mold or the like, for example, in the case of a spiral channel where all the circumferential passages are parallel, the number of mold divisions increases to avoid undercut. As shown in FIG. 6, in the coolant passage 15 of the present embodiment, the oblique passages are concentrated and arranged in one direction in the circumferential direction, so that the mold can be pulled out when the collapsible core is manufactured. By reducing and simplifying the configuration, costs can be reduced. Here, even if the protrusion for holding the collapsible core in the mold is provided in the coolant passage, the effect of the present invention does not change.

The coolant passage 15 continuously circulates inside the center housing 11, and the walls that partition the coolant passage function as ribs, and the reduction in rigidity of the center housing 11 due to the provision of the coolant passage can be suppressed. Therefore, the stator 3 fixed inside the center housing 11 can be prevented from being deformed by the magnetic excitation force, and magnetic noise can be reduced.

As shown in FIG. 7, the stator 3 may be a combination of divided stator cores each having a stator coil wound thereon.

The second embodiment will be described with reference to FIGS. However, the description of the same parts as those in the first embodiment is omitted.

In this embodiment, a gap between the outer housing 17 and the inner housing 18 is sealed with an O-ring 19 to form a coolant passage 15. Boundary walls 181 for partitioning the circumferential passages and the oblique passages are formed on the outer periphery of the substantially cylindrical inner housing 18, and O-ring grooves 185 are formed on both ends of the outer periphery in the axial direction. The oblique passages connecting the circumferential passages of the coolant passage 15 partitioned by the boundary wall 181 are not folded back, and the flow direction of the circumferential passages is the same in each stage, so there is no stagnation and the pressure loss increases. Can be suppressed.

The inner housing 18 is cast by die casting or the like, and the boundary wall 181 and the O-ring groove 185 are formed by a mold, which is suitable for mass production. By arranging the coolant introduction port 111, the coolant discharge port 112, and the

oblique passages

161 and 162 in one direction on the outer peripheral side, the direction of removing the mold of the inner housing 18 is reduced, and the configuration is simplified. Can reduce costs.

The outer periphery of the inner housing 18 is contacted and fixed to the inner peripheral portion of the outer housing 17 by a method such as shrink fitting or press-fitting, and is in contact with the inertial force caused by vibration acting on the inner housing 18 and the stator 3 or the torque reaction force of the motor. The fastening allowance is set so that a fastening force that does not slip the surface is generated. The fastening allowance is provided between the outer peripheral surface of the boundary wall 181 of the inner housing 18 and the inner peripheral surface of the outer housing 17. Since the boundary wall 181 continuously circulates around the outer periphery of the inner housing 18 and the fastening force of the inner housing 18 can be obtained over the entire circumference, the stator 3 fixed to the inner side of the inner housing 18 is caused by the magnetic excitation force. Deformation can be suppressed and magnetic noise can be reduced.

The O-ring that seals the coolant passage 15 is extrapolated from the outside in the axial direction to an O-ring groove 185 provided on the outer periphery of the inner housing 18. In order to extrapolate the O-ring, it is desirable that there is no protrusion on the outer periphery of the inner housing 18 and the O-ring groove 185 is close to both ends of the inner housing 18. According to the present invention, since the inner housing 18 is fixed by shrink fitting or press-fitting, it is not necessary to provide a protrusion such as a flange for fixing on the outer periphery, so that the O-ring can be easily attached.

As shown in FIG. 10, the stator 3 may be a combination of divided stator cores each having a stator coil wound thereon.

In addition, this invention is not limited to an above-described Example, Various modifications are included.
For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Rotating electrical machine 3 Stator 4 Rotor 5 Bearing 11 Center housing 12 Front housing 13 Rear housing 15 Coolant passage 16 Skew passage 17 Outer housing 18 Inner housing 19 O-ring 31 Stator core 32 Stator coil 41 Rotor core 44 Rotor shaft 111 Coolant inlet 112 Coolant outlet 151 Circumferential passage (first stage)
152 Circumferential passage (second stage)
153 Circumferential passage (third stage)
161 Skew passage (first stage)
162 Skew passage (second stage)
181 Boundary wall 185 O-ring groove

Claims

A stator,
A rotor held rotatably inside the stator through a predetermined gap;
A coolant passage located in the outer periphery of the stator and formed in the housing,
The coolant passage is
A coolant inlet provided at one end;
A coolant outlet provided at the other end;
A plurality of axially arranged circumferential passages that go straight in the circumferential direction;
Each of the circumferential passages is configured by an oblique passage connecting the axial passages,
A rotating electrical machine in which the circumferential passage and the skew passage are connected such that the flow direction of the coolant in each circumferential passage is the same in the circumferential direction.
In the rotating electrical machine according to claim 1,
A rotating electrical machine in which the coolant passage is formed inside an integrally formed housing.
In the rotating electrical machine according to claim 1,
A rotating electrical machine in which the coolant passage is formed in a gap between two inner and outer housings.
In the rotary electric machine according to any one of claims 1 to 3,
A rotating electrical machine in which the coolant introduction port and the coolant discharge port are arranged on different axes in the rotation axis direction of the rotor.
In a rotating electrical machine having a plurality of cooling fluid passages that circulate in the circumferential direction between an inner wall portion provided on the outer periphery of the stator and an outer wall provided on the outer periphery thereof,
The cooling water passage is
Two side walls forming both axial side surfaces;
A dividing wall formed between the two side walls,
A continuous circulation path formed by the dividing wall and the side wall is formed,
An inlet and an outlet are formed at the start and end of the circuit path, respectively.
At least a part of the dividing wall is provided between the inlet portion and the outlet portion,
A rotating electrical machine in which the entrance and the exit are partitioned by a part of the dividing wall.
In the rotating electrical machine according to claim 5,
A rotating electrical machine in which a part of the dividing wall that partitions the inlet portion and the outlet portion is skewed with respect to the circulating fluid passage.