JP2003158841A - Stator for rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce draft loss in a stator air duct to efficiently cool a stator coil and a stator core. SOLUTION: In an air duct 5 in an air supply section, cooling gas flows from the outer radius side of a stator to the inner radius side. A wedge 8 is inserted into the opening of a coil slot 6 to lock and hold a stator coil 7. The wedge 8 is so formed in terms of cross-sectional shape that the portion of the wedge mated with a stator coil 7 is the diameter thereof and the portion thereof inside the position of mating with the stator coil 7 is in a semi-circular and projected shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator of a rotary electric machine provided with a stator core in which thin plates are laminated, and particularly to improve ventilation cooling characteristics of the stator core and a stator coil housed in the core slot. The present invention relates to a stator of a rotating electric machine.

[0002]

2. Description of the Related Art As a conventional stator of a rotary electric machine, there is one that adopts the following ventilation cooling structure.

24 and 25 show an example of a stator of such a rotary electric machine, and FIG. 24 is an axial sectional view.
FIG. 25 is a sectional view of the ventilation duct portion of the stator.

24 and 25, a stator 1 of a rotating electric machine has a stator core 3 formed by laminating thin plates 2 and a plurality of inner spacing pieces 4 with an appropriate spacing in the axial direction. The ventilation duct portions 5 are formed by radially inserting the ventilation duct portions at predetermined intervals.

Further, a plurality of coil slots 6 are provided in the stator core 3, and a stator coil 7 consisting of an outer diameter side stator coil 7U and an inner diameter side stator coil 7L is inserted into each of these coil slots 6. By fixing the slot openings with the wedges 8, a stator of the rotating electric machine is constructed.

In this case, the inner peripheral surface 8a of the wedge 8 has a structure retracted to the outer peripheral side with respect to the tooth tip portion 9 of the core, and at the inner diameter side opening of the ventilation duct 5, the inner peripheral end of the inner spacing piece 4T. The structure is such that the portion 4t projects closer to the axial center of the stator core 3 than the inner peripheral surface 8a of the wedge 8.

Although not shown, the stator core 3 is fixed by tightening both ends. The inner spacing piece 4 is composed of an inner spacing piece 4S having a length reaching the slot bottom portion 10 and an inner spacing piece 4T having a length reaching the slot tooth top portion 9 in order to maintain close contact with the thin plates 2 on both sides between the stacked layers.

In this case, the inner peripheral end 4t of the inner spacing piece 4T
In order to maintain close contact with the laminated thin plate 2, is inserted to the tip of the iron core as much as possible.

A rotor 15 is rotatably provided inside the stator core 3 with an air gap 14 therebetween.

When a rotating electric machine provided with such a stator 1 is operated, heat is generated especially by the current flowing through the stator coil 7, and heat is also generated because eddy current is also generated in the stator core 3.

To cool them, a refrigerant gas 11 is made to flow into the ventilation duct 5 to cool the stator coil 7 and the stator core 3.

By the way, the ventilation duct 5 of the stator core 3
As shown in FIG. 26, the air is divided into two types: an air supply section 12 in which the cooling gas 11 flows from the outer circumference of the stator to the inner circumference side and an exhaust section 13 that flows from the inner circumference side of the stator to the outer circumference side. These sections 12 and 13 are arranged alternately in the core axis direction. The cooling gas 11 is discharged from the fans attached to both ends of the rotor, and the outer peripheral side of the stator core 3,
The air is supplied to the air gap 14 existing between the stator core 3 and the rotor 15 from the inside of the rotor 15 and the end of the stator core.

Cooling gas 1 flowing to the outer peripheral side of the stator core 3
1 cools the stator core 3 and the stator coil 7 through the ventilation duct 5 of the air supply section 12, and the air gap 1
It is discharged to 4. The cooling gas 11 discharged from the air supply section 12 and the cooling gas 11 directly flowing into the air gap 14 from the end of the iron core axially flow in the air gap 14 and are supplied to the ventilation duct 5 of the exhaust section 13.

At this time, the cooling gas 11 which has passed through the rotor 15 and is exhausted from the rotor surface also joins the air gap 14, and the stator coil and the stator core 3 are passed through the exhaust section 13. It is cooled and discharged to the outer circumference of the stator.

In this case, the flow of the cooling gas 11 in the air gap 14 has a certain peripheral velocity due to the friction between the cooling gas discharged from the rotor 15 and the rotor surface.

The cooling gas 11 flowing out from the outer peripheral side of the stator is cooled by a cooler (not shown) and then circulates to the fan again.

[0017]

In the stator of the rotary electric machine having such a ventilation cooling structure, the air supply section 12 in which the cooling gas 11 flows from the stator outer diameter side to the inner diameter side has the following problems. .

The problem will be described below with reference to FIGS. 27 and 28.

FIG. 27 shows changes in the total pressure, static pressure and dynamic pressure in the ventilation duct 5 calculated by numerical calculation of the flow state of the cooling gas 11 in the ventilation duct 5 of the air supply section 12.

In FIG. 27, the cooling gas 11 that has flowed in from the outer peripheral side of the stator is wedge 8 that holds and holds the stator coil 7.
Up to the inner peripheral position, since the flow passage area becomes narrower as it moves to the inner diameter side, the total pressure value gradually decreases due to an increase in friction loss proportional to the square of the flow velocity.

On the other hand, on the downstream side of the inner peripheral position of the wedge 8, the dynamic pressure (flow velocity) decreases, but the dynamic pressure is hardly reduced to the static pressure, so that the total pressure suddenly decreases. This phenomenon is caused by the rapid expansion of the flow on the downstream side of the inner peripheral position of the wedge 8.

The total pressure reduction amount on the downstream side of the inner peripheral position of the wedge 8 not only occupies about 60% of the total ventilation loss of the ventilation duct 5, but also has a small flow velocity (dynamic pressure) for cooling the stator. Therefore, it is an important technical issue to improve the cooling performance of the rotating electric machine to reduce the total pressure decrease amount of the same portion.

Further, the exhaust section 13 in which the cooling gas flows from the inner diameter side of the stator to the outer diameter side thereof has the following problems.

FIG. 28 shows the flow of the cooling gas 11 in the ventilation duct 5 of the exhaust section 13, and FIG.
Reference numeral 9 shows changes in total pressure, static pressure and dynamic pressure in the ventilation duct 5 calculated by numerical calculation.

In FIGS. 28 and 29, the cooling gas 11 flowing in the air gap 14 in the circumferential direction is rapidly changed in the radial direction by the wedge 8 on the inner circumferential portion of the ventilation duct 5 and the inner spacing piece 4T. The flow separation regions 16 and 17 are formed on the downstream side of the wedge 8 and the inner spacing piece 4T, which causes a sudden decrease in the total pressure in the inner peripheral portion of the ventilation duct 5. The separation regions 16 and 17 extend to the downstream regions of the left duct 5a and the right duct 5b, narrow the main flow region of the flow of the left duct 5a and the right duct 5b, and induce an increase in the average flow velocity of the main flow region. Therefore, the friction loss proportional to the product of the square of the flow velocity and the contact area with the cooling gas 11 is increased, and as a result, it is also a factor of increasing the total pressure decrease amount on the outer peripheral side of the ventilation duct 5. .

The total pressure reduction amount of the inner peripheral portion of the ventilation duct 5 not only occupies about 50% of the total ventilation loss of the ventilation duct 5, but the separation areas 16 and 17 which are the main factors are the ventilation duct 5. Since it also induces a decrease in the total pressure on the outer peripheral side and a decrease in the contact area with the cooling gas 11, it is important to reduce the total pressure decrease amount of the same portion in order to improve the cooling performance of the rotating electric machine. It has become a technical issue.

The present invention has been made in view of the above circumstances, and fixes a rotary electric machine capable of reducing the ventilation loss in the stator ventilation duct and efficiently cooling the stator coil and the stator core. The purpose is to provide children.

Another object is to reduce the ventilation loss in the stator ventilation duct so that the cooling gas can be efficiently circulated with a small fan power.

[0029]

In order to achieve the above object, the present invention constitutes a stator of a rotary electric machine by the following means.

The invention corresponding to claim 1 is a cylindrical stator core formed by laminating thin plates, and a stator coil inserted in a coil slot on the inner peripheral side of the stator core.
A wedge inserted into the opening of the coil slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spaces between the thin plate laminations of a predetermined number of sheets. Ventilation ducts for circulating cooling gas are formed along the radial direction of the stator core by arranging the pieces radially at appropriate intervals, and at least both side surfaces of the stator core are provided for each ventilation duct. The periphery is defined by the inner spacing piece and the thin plate spaced by the inner spacing piece at a position facing each other, and the cooling gas is divided into left and right from the outer peripheral side of the stator with the stator coil interposed therebetween. In a stator of a rotating electric machine configured to be divided into a left duct and a right duct to be introduced, a cross-sectional shape of the wedge is a joining position with the stator coil as a base surface, and a joining position with the stator coil. Inner diameter side Forming a narrow protrusion than the width of said slot.

According to a second aspect of the present invention, in the stator of the rotating electric machine according to the first aspect of the invention, the cross-sectional shape of the convex portion of the wedge is fixed at the left end portion of the joining portion with the stator coil. The shape is defined by an arc that contacts the child coil surface and an arc that contacts the stator coil surface at the right end of the joining portion with the stator coil.

According to a third aspect of the invention, in the stator of the rotating electric machine according to the first aspect of the invention, the cross-sectional shape of the convex portion of the wedge is fixed at the left end portion of the joining portion with the stator coil. The shape is defined by an elliptic arc that is in contact with the child coil surface and an elliptic arc that is in contact with the stator coil surface at the right end of the joining portion with the stator coil.

According to a fourth aspect of the present invention, in the stator of the rotating electric machine according to the first aspect of the present invention, the cross-sectional shape of the convex portion of the wedge is fixed at the left end portion of the joint portion with the stator coil. A free curve that contacts the child coil surface and projects to the left,
The shape is such that it is surrounded by a free curve protruding rightward in contact with the stator coil surface at the right end of the joining portion with the stator coil.

According to a fifth aspect of the present invention, in the stator of the rotating electric machine according to the first aspect of the invention, the cross-sectional shape of the convex portion of the wedge is fixed at the left end portion of the joint portion with the stator coil. A compound curve formed by an arc contacting the child coil surface and a tangent line at the lower part of the same arc, and an arc contacting the stator coil surface at the right end of the joining part with the stator coil And a complex curve formed by the tangent line of and.

According to a sixth aspect of the present invention, in the stator of the rotating electric machine according to the first aspect of the invention, the cross-sectional shape of the convex portion of the wedge is such that the base surface of the joint portion with the stator coil is the base. In addition, the inner diameter side of the joining position with the stator coil is triangular.

According to a seventh aspect of the present invention, in the stator of the rotating electric machine according to any one of the first to sixth aspects of the invention, the convex portion of the wedge has an inner diameter portion of the wedge and the stator coil. It is a shape that is cut by a straight line parallel to the joining portion with.

The invention corresponding to claim 8 is the stator of a rotating electric machine according to any one of claims 1 to 6, wherein the convex portion of the wedge has an inner diameter portion of the wedge as a stator core. It is a shape cut along a concentric arc surface.

According to a ninth aspect of the present invention, a cylindrical stator core formed by stacking thin plates, and a stator coil inserted into a coil slot on the inner peripheral side of the stator core are provided.
A wedge inserted into the opening of the coil slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spaces between the thin plate laminations of a predetermined number of sheets. Ventilation ducts for circulating cooling gas are formed along the radial direction of the stator core by arranging the pieces radially at appropriate intervals, and at least both side surfaces of the stator core are provided for each ventilation duct. The periphery is defined by the inner spacing piece and the thin plate spaced by the inner spacing piece at a position facing each other, and the cooling gas is divided into left and right from the outer peripheral side of the stator with the stator coil interposed therebetween. In a stator of a rotary electric machine configured to be divided into a left-side duct and a right-side duct to be introduced, a flow passage width in the axial direction of the ventilation duct is made wider toward a duct opening portion from a joint portion with a stator coil. Things That.

According to a tenth aspect of the present invention, in the stator of a rotating electric machine according to any one of the first to eighth aspects, the axial duct width of the ventilation duct is joined to the stator coil. It is wider toward the duct opening than the part.

According to an eleventh aspect of the present invention, a cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and the coil are provided. A wedge that is inserted into the opening of the slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spacing pieces between a predetermined number of the thin plate laminations. A ventilation duct for cooling gas flow is formed along the radial direction of the stator core by radially arranging at appropriate intervals, and at least both side surfaces of the stator core are opposed to each ventilation duct. The inner space piece and the thin plate separated by the inner space piece define a perimeter at a position where cooling gas is introduced from the outer peripheral side of the stator in the left and right directions with the stator coil interposed therebetween. Left duct and right In the stator of the rotary electric machine which is constituted by divided into a duct, in which the inner circumferential position of the wedge was consistent with the stator core inner diameter in the axial direction region excluding the ventilation duct part.

According to a twelfth aspect of the present invention, a cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on the inner peripheral side of the stator core, and the coil A wedge that is inserted into the opening of the slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spacing pieces between a predetermined number of the thin plate laminations. A ventilation duct for cooling gas flow is formed along the radial direction of the stator core by radially arranging at appropriate intervals, and at least both side surfaces of the stator core are opposed to each ventilation duct. The periphery is defined by the inner spacing piece and the thin plate spaced by the inner spacing piece at a position where cooling gas flowing along the rotation direction of the rotor is sandwiched between the left and right sides of the stator coil. Introduced separately In a stator of a rotary electric machine configured to be divided into a side duct and a right duct, the cross-sectional shape of the wedge has a joint portion with the stator coil as a base surface, and an inner diameter side from a joint position with the stator coil. Is formed in a convex portion narrower than the width dimension of the slot.

An invention corresponding to claim 13 is claim 12
In the stator of the rotating electric machine according to the invention, the cross-sectional shape of the convex portion of the wedge is a free-form curve on the lower side in contact with the stator coil surface at the left end portion and the right end portion of the joint portion with the stator coil. It has a defined shape.

The invention corresponding to claim 14 is claim 12
Alternatively, in the stator of a rotating electric machine according to the invention of claim 13, the inner space end position of the inner spacing piece is located between the joint portion with the stator coil and the inner diameter end position of the wedge.

According to a fifteenth aspect of the present invention, a cylindrical stator core constituted by laminating thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and the coil are provided. A wedge that is inserted into the opening of the slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spacing pieces between a predetermined number of the thin plate laminations. A ventilation duct for cooling gas flow is formed along the radial direction of the stator core by radially arranging at appropriate intervals, and at least both side surfaces of the stator core are opposed to each ventilation duct. The periphery is defined by the inner spacing piece and the thin plate spaced by the inner spacing piece at a position where cooling gas flowing along the rotation direction of the rotor is sandwiched between the left and right sides of the stator coil. Introduced separately In the stator of the rotary electric machine which is constituted by divided into a side duct and the right duct, the inner diameter end shape of the inner distance piece is obtained by forming the convex portion formed by an arc surface on the inner diameter side.

The invention corresponding to claim 16 is claim 12
According to the stator of a rotating electric machine of the invention according to any one of claims 14 to 14, the inner spacing end shape of the inner spacing piece is formed in a convex portion formed by an arc surface on the inner diameter side.

According to a seventeenth aspect of the present invention, a cylindrical stator core formed by laminating thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and the coil are provided. A wedge that is inserted into the opening of the slot to lock and hold the stator coil from the inner peripheral side of the stator core, and the stator core has a plurality of inner spacing pieces between a predetermined number of the thin plate laminations. A ventilation duct for cooling gas flow is formed along the radial direction of the stator core by radially arranging at appropriate intervals, and at least both side surfaces of the stator core are opposed to each ventilation duct. The periphery is defined by the inner spacing piece and the thin plate spaced by the inner spacing piece at a position where cooling gas flowing along the rotation direction of the rotor is sandwiched between the left and right sides of the stator coil. Introduced separately In a stator of a rotating electric machine configured to be divided into a side duct and a right duct, the inner peripheral position of the wedge is made to coincide with the inner diameter of the stator core in an axial portion excluding the ventilation duct portion. .

According to an eighteenth aspect of the present invention, in the stator of the rotating electric machine according to the first aspect or the twelfth aspect of the invention, the cross-sectional shape of the convex portion of the wedge is the same as that of the stator coil. It is a semi-circular shape having a diameter at the joint portion or a semi-elliptical shape having a minor axis diameter.

The invention corresponding to claim 19 is the stator of the rotating electric machine according to any one of claims 1 to 10 and 12 to 16, wherein the ventilation duct portion is located inside the wedge. It is made to match the inner diameter of the stator in the axial part except for.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a stator of a rotary electric machine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a basic configuration diagram showing a cross section of a main part of a first embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the wedge 8 for locking and holding the stator coil 7 has a cross-sectional shape with respect to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner / outer diameter side. The diameter of the joint portion with the stator coil is set, and the inner diameter side from the joint position with the stator coil 7 is formed into a semicircular convex portion.

FIG. 2 shows changes in the radial direction of the total pressure, static pressure, and dynamic pressure in the ventilation duct 5 according to the present embodiment, which are calculated by numerical calculation, in comparison with the conventional wedge-shaped one. .

By adopting the wedge shape of the present embodiment,
As is clear from the drawing, it can be confirmed that the amount of total pressure drop is greatly improved on the inner peripheral side of the ventilation duct 5, and the pressure loss of the entire ventilation duct is reduced by about 40%.

As can be seen from the flow pattern at the outlet of the ventilation duct 5 calculated by numerical calculation as shown in FIG. 3, this phenomenon is caused by forming the wedge 8 into a semi-circular shape, so that the left duct 5a and the right duct are formed. The dynamic pressure on the downstream side of the wedge 8 becomes a static pressure by diverting the flow of the flow of 5b so that the flow on the downstream side of the wedge 8 can be easily merged and by making the expansion rate of the flow passage area on the downstream side of the wedge 8 gentle. This is due to the improved recovery rate.

Therefore, with such a structure, the ventilation loss in the stator ventilation duct 5 is reduced, and the stator coil 7 and the stator core 1 can be efficiently cooled.

FIG. 4 is a basic configuration diagram showing a cross section of a main part of a second embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In this embodiment, the wedge 8 for locking and holding the stator coil 7 has a sectional shape with respect to the ventilation duct 5 of the air supply section through which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. The joining portion with the stator coil has a short axis diameter, and the inner diameter side from the joining position with the stator coil 7 is formed into a semi-elliptical convex portion.

Even with such a configuration, the same operation and effect as those of the first embodiment can be obtained.

FIG. 5 is a basic configuration diagram showing a cross section of a main part of a third embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the cross-sectional shape of the wedge 8 that holds and holds the stator coil 7 with respect to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner diameter side is A shape that is surrounded by an arc that contacts the stator coil surface 8a at the left end of the joining portion with the stator coil 7 and an arc that contacts the stator coil surface 8b at the right end of the joining portion with the stator coil 7. Is.

Even with such a structure, the same operation and effect as those of the first embodiment can be obtained.

FIG. 6 is a basic configuration diagram showing a cross section of a main portion of a stator of a rotary electric machine according to the present invention in a fourth embodiment. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the wedge 8 for holding and holding the stator coil 7 has a cross-sectional shape with respect to the ventilation duct 5 of the air supply section through which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. A shape surrounded by an elliptic arc that contacts the stator coil surface 8a at the left end of the joining portion with the stator coil 7 and an elliptic arc that contacts the stator coil surface 8b at the right end of the joining portion with the stator coil 7. It is a thing.

Even with such a configuration, the same operation and effect as those of the first embodiment can be obtained.

FIG. 7 is a basic configuration diagram showing a cross section of a main part of a stator of a rotating electric machine according to the present invention in a fifth embodiment. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the cross-sectional shape of the wedge 8 that holds and holds the stator coil 7 is fixed to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. , A free curve that is in contact with the stator coil surface 8a at the left end of the joining portion with the stator coil and projects to the left, and the stator coil surface 8 at the right end of the joining portion with the stator coil 7.
It has a shape surrounded by a free curve which is in contact with b and projects to the right.

Even with such a configuration, the same operation and effect as those of the first embodiment can be obtained.

FIG. 8 is a basic configuration diagram showing a cross section of a main portion of a sixth embodiment of a stator of a rotary electric machine according to the present invention.

In the present embodiment, the wedge 8 for holding and holding the stator coil 7 has a cross-sectional shape with respect to the ventilation duct 5 of the air supply section through which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. A composite curve consisting of an arc that contacts the stator coil surface 8a at the left end of the joint with the stator coil 7 and a tangent line at the lower end of the arc, and the right end of the joint with the stator coil 7. Is surrounded by a circular arc that is in contact with the stator coil surface 8b and a complex curve constituted by a tangent line at the lower end of the circular arc.

Even with such a structure, the same operation and effect as those of the first embodiment can be obtained.

FIG. 9 is a basic configuration diagram showing a cross section of a main part of a seventh embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the cross-sectional shape of the wedge 8 for holding and holding the stator coil 7 is fixed to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner / outer diameter side. The joint portion with the stator coil 7 is the bottom side, and the inner diameter side from the joint position with the stator coil 7 is formed into a triangular convex portion.

Even with such a configuration, the same operation and effect as those of the first embodiment can be obtained.

FIG. 10 is a basic configuration diagram showing a cross section of a main portion of a rotor of a rotary electric machine according to the present invention in an eighth embodiment. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the wedge 8 for locking and holding the stator coil 7 has a sectional shape of the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. Any one of the wedge-shaped wedges of the above-described first to seventh embodiments, here, in the wedge 8 of the first embodiment, the inner diameter portion thereof is a straight line parallel to the joint portion with the stator coil 7. It is cut into a shape.

Even with such a structure, the same operation and effect as those of the first embodiment can be obtained.

FIG. 11 is a basic configuration diagram showing a cross section of a main portion of a rotor of a rotary electric machine according to a ninth embodiment of the present invention.

In the present embodiment, the cross-sectional shape of the wedge 8 which holds and holds the stator coil 7 is fixed to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner and outer diameter sides thereof. The wedge in any one of the above-described first to seventh embodiments, here, the wedge 8 in the first embodiment, has an inner diameter portion cut into an arc concentric with the stator.

Even with such a structure, the same operation and effect as those of the first embodiment can be obtained.

FIG. 12 is a basic block diagram showing the essential parts of a stator of a rotating electric machine according to the tenth embodiment of the present invention.
The same parts as those in FIG. 25 are designated by the same reference numerals, and the description thereof will be omitted. Here, different points will be described.

In the present embodiment, the flow passage width in the axial direction of the ventilation duct 5 on the stator inner diameter side is set with respect to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side of the stator to the inner diameter side. A predetermined size is widened toward the duct opening from the joint with the stator coil 7.

With such a structure, the expansion rate of the flow passage area on the downstream side of the wedge 8 becomes gentle, and the ratio of the dynamic pressure on the downstream side of the wedge 8 to the static pressure can be improved. Therefore, the pressure loss in the inner peripheral portion of the ventilation duct 5 is reduced, so that the stator coil 7 and the stator core 3 can be efficiently cooled.

In the first to ninth embodiments described above, the flow passage width of the ventilation duct 5 in the axial direction is widened by a predetermined dimension from the joint with the stator coil 7 toward the duct opening. Good.

In this way, the operation and effect of the first to ninth embodiments and the operation and effect of the tenth embodiment can be obtained at the same time.

FIG. 13 is a perspective view showing the basic structure of essential parts of an eleventh embodiment of the stator for a rotary electric machine according to the present invention.

In this embodiment, with respect to the ventilation duct 5 of the air supply section in which the cooling gas 11 flows from the outer diameter side to the inner diameter side of the stator, the inner peripheral position of the wedge 8 is set to the axial position excluding the ventilation duct 5 part. The directional portion is made to match the inner diameter of the stator.

As a result, the axial groove surrounded by the iron core tooth top portion 9 and the wedge 8 is eliminated, so that the dynamic pressure of the cooling gas 11 flowing into the main axial groove is restored to the static pressure without loss. Become. Therefore, the stator coil 7 and the stator core 3 can be efficiently cooled by reducing the pressure loss at this portion.

Incidentally, the above-mentioned first to first embodiments
In the zero embodiment, the inner peripheral position of the wedge 8 may be made to coincide with the inner diameter of the stator at the axial portion except the ventilation duct 5.

In this way, the first to tenth embodiments are performed.
It is possible to obtain the effect of the embodiment and the effect of the eleventh embodiment at the same time.

As described above in detail, the stator having the structure as in the first to eleventh embodiments is provided for the ventilation duct of the air supply section in which the cooling gas flows from the outer diameter of the stator to the inner diameter side. As a result, the pressure loss at the outlet of the ventilation duct can be significantly reduced, and the stator coil and the stator core can be efficiently cooled. Furthermore, this reduction in ventilation loss enables the cooling gas to be efficiently supplied with less fan power. It can be circulated in the flow path of the rotary electric machine.

FIG. 14 is a basic configuration diagram showing a cross section of a main part of a twelfth embodiment of a rotor of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In this embodiment, the cross-sectional shape of the wedge 8 for holding and holding the stator coil 7 is fixed to the ventilation duct 5 of the exhaust section through which the cooling gas flows from the inner diameter side to the outer diameter side of the stator. The diameter of the joint portion with the coil 7 is set, and the inner diameter side of the joint portion with the stator coil 7 is formed into a semicircular convex portion.

FIG. 15 shows a change in the total pressure in the ventilation duct 5 according to the present embodiment in the radial direction, which is calculated by numerical calculation, in comparison with a conventional wedge-shaped one.

By adopting the wedge shape of this embodiment,
As is clear from the figure, it can be confirmed that the amount of sudden total pressure decrease on the inner peripheral side of the ventilation duct 5 is improved and the pressure loss of the entire ventilation duct is reduced by about 50%.

This phenomenon is caused by forming the wedge 8 into a semicircular shape, as can be seen from the flow pattern at the inlet of the ventilation duct 5 calculated by numerical calculation as shown in FIG.
The flow separation region that occurred on the downstream side of the wedge 8 disappeared,
This is because the total pressure reduction amount in the same portion is reduced and the friction loss in the same portion is reduced due to the expansion of the mainstream region on the downstream side of the ventilation duct 5.

Therefore, with such a structure, the ventilation loss in the stator ventilation duct 5 is reduced, and the stator coil 7 and the stator core 1 can be efficiently cooled.

FIG. 17 is a basic configuration diagram showing a cross section of a main part of a stator of a rotary electric machine according to a thirteenth embodiment of the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In this embodiment, the cross-sectional shape of the wedge 8 that holds and holds the stator coil 7 is fixed to the ventilation duct 5 of the exhaust section in which the cooling gas flows from the inner diameter side to the outer diameter side of the stator. The joint portion with the coil has a minor axis diameter, and the inner diameter side from the joint position with the stator coil 7 is formed into a semi-elliptical convex portion.

Even with such a configuration, the same operation and effect as in the twelfth embodiment can be obtained.

FIG. 18 is a basic configuration diagram showing a cross section of a main portion of a fourteenth embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In the present embodiment, the cross-sectional shape of the wedge 8 that holds and holds the stator coil 7 is fixed to the ventilation duct 5 of the exhaust section through which the cooling gas flows from the inner diameter side of the stator to the outer diameter side thereof. The left and right ends of the joint with the coil 7 are in contact with the stator coil surfaces 8a and 8b, and a convex portion having a shape defined by a free curve is formed on the lower side.

Even with such a structure, the same operation and effect as those of the twelfth embodiment can be obtained.

FIG. 19 is a basic block diagram showing the essential parts of a stator of a rotary electric machine according to the fifteenth embodiment of the present invention.
The same parts as those in FIG. 28 are designated by the same reference numerals, and the description thereof will be omitted. Here, different points will be described.

In the present embodiment, the inner diameter end of the inner spacing piece 4T is joined to the stator coil 7 and the wedge 8 with respect to the ventilation duct 5 of the exhaust section through which the cooling gas flows from the inner diameter side of the stator to the outer diameter side. It is located between the portion and the inner diameter end position of the wedge 8.

FIG. 20 shows a change in the total pressure in the ventilation duct 5 according to the present embodiment calculated by numerical calculation and the wedge shape of the thirteenth embodiment for comparison.

By making the wedge shape of the present embodiment, as is clear from the figure, the amount of sudden total pressure decrease on the inner peripheral side of the ventilation duct 5 is improved, and the pressure loss of the entire ventilation duct is about 20%. It can be confirmed that it is decreasing.

As can be seen from the flow pattern at the inlet of the ventilation duct 5 calculated by numerical calculation as shown in FIG. 21, this phenomenon shows that the inner diameter end position of the inner spacing piece 4T is the same as the stator coil 7 and the wedge 8. By arranging it between the joining portion of the above and the inner diameter end position of the wedge 8, the separation region of the flow generated on the downstream side of the inner spacing piece 4T becomes small, and the total pressure reduction amount at the portion is reduced. At the same time, this is because the mainstream region on the downstream side of the ventilation duct 5 is expanded to reduce the friction loss at the same portion.

Therefore, with such a structure, the ventilation loss in the stator ventilation duct 5 is reduced, and the stator coil 7 and the stator core 1 can be efficiently cooled.

Even if the inner spacing piece of this embodiment is applied to the stator of the rotating electric machine according to the thirteenth and fourteenth embodiments, the same action and effect can be obtained.

FIG. 22 is a basic configuration diagram showing a cross section of a main portion of a sixteenth embodiment of a stator of a rotary electric machine according to the present invention. The same parts as those in FIG. Omitted, different points will be described here.

In this embodiment, with respect to the ventilation duct 5 of the exhaust section in which the cooling gas flows from the stator inner diameter side to the outer diameter side, the shape of the inner diameter end portion of the inner spacing piece 4T is rounded on the inner diameter side. The convex portions are formed.

With such a configuration, the fifteenth
Similar to the embodiment described above, the separation region of the flow generated on the inner diameter end downstream side of the inner spacing piece 4T becomes smaller. Therefore, the ventilation loss in the ventilation duct of the stator is reduced, and the stator coil 7 and the stator core 1 can be efficiently cooled.

In the twelfth to fourteenth embodiments described above, as in the present embodiment, the inner space end portion 4T is formed by forming a convex portion with a rounded inner diameter end, thereby forming Fourteenth to seventeenth embodiments
The effect of 9 and the effect of the 18th embodiment can be obtained at the same time.

FIG. 23 is a perspective view showing the basic structure of the essential parts of a stator of a rotary electric machine according to the seventeenth embodiment of the present invention.

In the present embodiment, the inner peripheral position of the wedge 8 is fixed to the ventilation duct 5 of the exhaust section through which the cooling gas flows from the inner diameter side of the stator to the outer diameter side, except for the ventilation duct 5 portion. It is designed to match the inner diameter of the child.

Even with such a structure, the axial groove 18 surrounded by the iron core tooth top portion 9 and the wedge 8 becomes long, and the main axial groove 1
Since there is no pressure loss generated when the cooling gas 11 flows in or out of the cooling gas 8, the stator coil 7 and the stator core 3 can be efficiently cooled by reducing the pressure loss at this portion.

In the stator of the rotating electric machine according to the twelfth to sixteenth embodiments described above, the inner peripheral position of the wedge 8 is made to coincide with the inner diameter of the stator at the axial portion excluding the ventilation duct 5 portion. You may do it.

By doing so, in addition to the effects of the twelfth to sixteenth embodiments, the effects of the seventeenth embodiment can be obtained.

As described above in detail, the stator having the structure as in the twelfth to seventeenth embodiments is used for the ventilation duct of the exhaust section in which the cooling gas flows from the outer diameter of the stator to the inner diameter side. This significantly reduces the pressure loss at the inlet of the ventilation duct and allows the stator coil and stator core to be efficiently cooled. Furthermore, this reduction in ventilation loss allows the cooling gas to rotate efficiently with less fan power. It can be circulated in the electric machine ventilation passage.

[0120]

As described above, according to the present invention, there is provided a stator for a rotary electric machine, which can reduce the ventilation loss in the stator ventilation duct and efficiently cool the stator coil and the stator core. it can.

Further, it is possible to provide the stator of the rotating electric machine which can reduce the ventilation loss in the stator ventilation duct and efficiently circulate the cooling gas with a small fan power.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram showing a cross section of a main part of a first embodiment of a stator of a rotary electric machine according to the present invention.

[FIG. 2] In the same embodiment, the total pressure in the ventilation duct,
FIG. 4 is a curve diagram showing changes in static pressure and dynamic pressure in the radial direction.

FIG. 3 is a diagram showing a flow pattern of a ventilation duct outlet portion in the embodiment.

FIG. 4 is a basic configuration diagram showing a cross section of a main part of a second embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 5 is a basic configuration diagram showing a cross section of a main part of a third embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 6 is a basic configuration diagram showing a cross section of a main part in a fourth embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 7 is a basic configuration diagram showing a cross section of a main part of a stator of a rotating electric machine according to a fifth embodiment of the present invention.

FIG. 8 is a basic configuration diagram showing a cross section of a main part in a sixth embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 9 is a basic configuration diagram showing a cross section of a main part of a stator of a rotating electric machine according to a seventh embodiment of the present invention.

FIG. 10 is a basic configuration diagram showing a cross section of a main part of a stator of a rotating electric machine according to an eighth embodiment of the present invention.

FIG. 11 is a basic configuration diagram showing a cross section of a main part in a ninth embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 12 is a basic configuration diagram showing a main part of a stator of a rotary electric machine according to a tenth embodiment of the present invention.

FIG. 13 is a perspective view showing a basic configuration of essential parts of an eleventh embodiment of a stator of a rotary electric machine according to the present invention.

FIG. 14 is a basic configuration diagram showing a cross section of a main part in a twelfth embodiment of a rotor of a rotary electric machine according to the present invention.

FIG. 15 is a curve diagram showing changes in the total pressure in the ventilation duct in the radial direction in the same embodiment.

FIG. 16 is a diagram showing a flow pattern of a ventilation duct inlet portion in the embodiment.

FIG. 17 is a basic configuration diagram of a stator of a rotary electric machine according to a fifteenth embodiment of the present invention.

FIG. 18 is a basic configuration diagram showing a cross section of a main part of a stator of a rotary electric machine according to a thirteenth embodiment of the present invention.

FIG. 19 is a basic configuration diagram showing a cross section of a main part of a stator of a rotary electric machine according to a fifteenth embodiment of the present invention.

FIG. 20 is a curve diagram showing changes in the total pressure in the ventilation duct in the radial direction in the same embodiment.

FIG. 21 is a view showing a flow pattern of a ventilation duct inlet portion in the same embodiment.

FIG. 22 is a basic configuration diagram showing a cross section of a main part of a stator of a rotary electric machine according to a sixteenth embodiment of the present invention.

FIG. 23 is a basic configuration diagram of a stator of a rotary electric machine according to a twentieth embodiment of the present invention.

FIG. 24 is a perspective view showing the basic structure of essential parts of a stator of a rotary electric machine according to a seventeenth embodiment of the present invention.

FIG. 25 is a cross-sectional view showing a ventilation duct portion of a conventional stator core.

FIG. 26 is a view showing a ventilation passage of cooling gas in a ventilation duct in a conventional stator core.

FIG. 27 is a curve diagram showing changes in total pressure, static pressure, and dynamic pressure in the ventilation duct in the conventional air supply section in the radial direction.

FIG. 28 is a schematic diagram showing a flow state of cooling gas in a ventilation duct in a conventional exhaust section.

FIG. 29 is a curve diagram showing changes in the total pressure, static pressure, and dynamic pressure in the ventilation duct in the conventional exhaust section in the radial direction.

[Explanation of symbols]

1: Stator core 1 2: Thin plate 3: Iron core 4,4S, 4T: Inner spacing piece 5: Ventilation duct section 6: Coil slot 7: Stator coil 7U: Stator coil on outer diameter side 7L: Inner diameter side stator coil 8: wedge 9: Iron core tooth tip 10: Bottom of slot 11: Refrigerant gas 12: Air supply section 13: Exhaust section 14: Air gap 15: rotor 16: Peeling area 17: peeling area 18: Axial groove

Continued front page    F-term (reference) 5H002 AA08 AA10 AB01 AB04 AC01                       AD06 AD07 AD09 AE07                 5H603 AA12 BB02 BB09 BB12 CA01                       CA05 CB02 CB24 CB26 CC04                       CC17 CD02 CD05 CD12 CD22                       CD32 CD33 CE05 CE13 EE12                       EE25 FA02 FA12 FA16                 5H604 AA01 AA03 BB04 BB10 BB14                       CC01 CC05 CC14 DA14 DB01                       PB02 PB03 QC04                 5H609 BB03 BB19 PP02 PP06 PP08                       PP09 QQ02 QQ03 QQ10 RR02                       RR17 RR35 RR36 RR37 RR42                       RR73

Claims (19)

[Claims] 1. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner circumference side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations of a predetermined number. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is located at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. And the thin plate separated by this inner spacing piece, the periphery is defined, and a left duct and a right duct into which cooling gas is introduced from the outer peripheral side of the stator in a left-right manner with the stator coil sandwiched therebetween. It is divided into In the stator of the rotating electric machine, the cross-sectional shape of the wedge is based on the joint portion with the stator coil, and the inner diameter side from the joint position with the stator coil is a convex portion narrower than the width dimension of the slot. A stator of a rotating electric machine characterized by being formed. 2. The stator for a rotating electric machine according to claim 1, wherein the convex portion of the wedge has a cross-sectional shape of an arc that is in contact with a stator coil surface at a left end portion of a joint portion with the stator coil, and the fixed portion. A stator for a rotating electric machine, characterized in that it is shaped so as to be surrounded by an arc that is in contact with a stator coil surface at a right end portion of a joining portion with a child coil. 3. The stator of a rotating electric machine according to claim 1, wherein the convex portion of the wedge has a cross-sectional shape of an elliptic arc that is in contact with a stator coil surface at a left end portion of a joint portion with the stator coil.
A stator for a rotating electric machine, characterized in that the stator coil surface is surrounded by an elliptic arc that is in contact with the stator coil surface at the right end of the joint portion with the stator coil. 4. The stator of the rotating electric machine according to claim 1, wherein the cross-sectional shape of the convex portion of the wedge is in contact with the stator coil surface at the left end of the joint portion with the stator coil and protrudes to the left. A stator for a rotating electric machine, characterized in that it is surrounded by a free curve and a free curve which is in contact with a stator coil surface at a right end portion of a joining portion with the stator coil and projects rightward. 5. The stator of a rotating electric machine according to claim 1, wherein the convex portion of the wedge has a cross-sectional shape that is the same as the arc that contacts the stator coil surface at the left end of the joint portion with the stator coil. A complex curve formed by a tangent line at a short portion, and a complex curve formed by an arc contacting the stator coil surface at the right end of the joining portion with the stator coil and a tangent line at the short portion under the same arc. A stator for a rotating electric machine, which is characterized by being surrounded by. 6. The stator of the rotating electric machine according to claim 1, wherein the convex portion of the wedge has a cross-sectional shape whose base is a base surface of a joint portion with the stator coil, and a joint position with the stator coil. A stator of a rotating electric machine, which has a triangular shape on the inner diameter side. 7. The stator of a rotary electric machine according to claim 1, wherein the convex portion of the wedge has an inner diameter portion of the wedge which is a straight line parallel to a joint portion with the stator coil. A stator for a rotating electric machine, which has a cut shape. 8. The stator for a rotary electric machine according to claim 1, wherein the convex portion of the wedge has a shape obtained by cutting an inner diameter portion of the wedge with an arc surface concentric with the stator core. A stator for a rotating electric machine, characterized in that 9. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner circumference side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations of a predetermined number. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is located at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. And the thin plate separated by this inner spacing piece, the periphery is defined, and a left duct and a right duct into which cooling gas is introduced from the outer peripheral side of the stator in a left-right manner with the stator coil sandwiched therebetween. It is divided into And the stator of the rotating electric machine, a stator of a rotary electric machine, characterized in that the axial channel width of the ventilation duct wider toward the duct opening from the joint portion between the stator coils. 10. The stator for a rotary electric machine according to claim 1, wherein the flow path width of the ventilation duct in the axial direction is wider than the joint with the stator coil toward the duct opening. A stator of a rotating electric machine characterized by the above. 11. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner circumference side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations of a predetermined number. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is located at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. And the thin plate separated by this inner spacing piece, the periphery is defined, and a left duct and a right duct into which cooling gas is introduced from the outer peripheral side of the stator in a left-right manner with the stator coil sandwiched therebetween. Divided into In the stator of the rotary electric machine, a stator of a rotary electric machine, characterized in that the inner circumferential position of the wedge was consistent with the stator core inner diameter in the axial direction region excluding the ventilation duct part. 12. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner circumference side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations of a predetermined number. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is located at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. A left duct in which the periphery is defined by the thin plate and the thin plate separated by the inner spacing piece, and cooling gas flowing along the rotation direction of the rotor is introduced left and right while sandwiching the stator coil. And the right duct In a stator of a rotating electric machine configured to be divided, the cross-sectional shape of the wedge is based on a joining portion with the stator coil as a base surface, and an inner diameter side from a joining position with the stator coil is a width dimension of the slot. A stator for a rotating electric machine, characterized by being formed in a narrow convex portion. 13. The stator of a rotary electric machine according to claim 12, wherein the convex portion of the wedge has a cross-sectional shape that is in contact with a stator coil surface at a left end portion and a right end portion of a joint portion with the stator coil. A stator of a rotating electric machine characterized by having a shape defined by a free curve on the side. 14. The stator of a rotary electric machine according to claim 12 or 13, wherein the inner space end position of the inner spacing piece is located between the joint portion with the stator coil and the inner diameter end position of the wedge. Characteristic rotating machine stator. 15. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner circumference side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations of a predetermined number. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is located at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. A left duct in which the periphery is defined by the thin plate and the thin plate separated by the inner spacing piece, and cooling gas flowing along the rotation direction of the rotor is introduced left and right while sandwiching the stator coil. And the right duct In classification to configured electric rotating machine stator, the stator of a rotary electric machine, characterized in that the inner diameter end shape of the inner distance piece is formed in the convex portion formed by an arc surface on the inner diameter side. 16. The stator of a rotary electric machine according to claim 12, wherein the inner space end piece has an inner diameter end shape formed on a convex portion formed by an arc surface on the inner diameter side. And the stator of the rotating electric machine. 17. A cylindrical stator core formed by stacking thin plates, a stator coil inserted into a coil slot on an inner peripheral side of the stator core, and a stator coil inserted into an opening of the coil slot. A wedge for locking and holding the stator coil from the inner peripheral side of the stator core, wherein the stator core has a plurality of inner spacing pieces radially arranged between the thin plate laminations for every predetermined number of sheets. And a ventilation duct for cooling gas flow is formed along the radial direction of the stator core, and the inner spacing piece is provided at a position facing at least both side surfaces of the stator core with respect to each ventilation duct. A peripheral area is defined by the thin plate separated by the inner spacing piece, and a left duct into which cooling gas flowing along the rotation direction of the rotor is introduced left and right while sandwiching the stator coil. To the right duct In the stator of a rotating electric machine configured by dividing the stator, the inner peripheral position of the wedge is made to coincide with the inner diameter of the stator iron core in an axial portion excluding the ventilation duct portion. . 18. The stator of a rotating electric machine according to claim 1, wherein the convex portion of the wedge has a semicircular cross section having a diameter at a joint portion with the stator coil. Alternatively, a stator of a rotary electric machine, which has a semi-elliptical shape with a minor axis diameter. 19. The method according to any one of claims 1 to 10 and 12.
The stator of the rotating electric machine according to any one of claims 16 to 16, wherein an inner peripheral position of the wedge is matched with an inner diameter of the stator at an axial portion excluding a ventilation duct portion. Child.