JPS6337587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling structure for a one-way rotating electric machine, and particularly provides an improved structure that can improve cooling performance.

2. Description of the Related Art Many open type electric motors having the structure shown in FIGS. 1 and 2 have been manufactured in the past. To explain the structure of this, 1 is a cylindrical housing with both ends open,
Bearing brackets 2a and 2b close both open ends of the housing 1, and are provided with air holes 10a and 10b. A cylindrical stator 3 is housed approximately in the center of the housing 1, and is provided with a coil 4 wound thereon. The back surface of the stator 3 is supported by a rib 1a protruding from the housing 1, and the rib 1a is located between the back surface of the stator 3 and the inner surface of the housing 1.
A ventilation path 1b for cooling air is formed along the direction a.
Reference numeral 5 denotes a rotating shaft rotatably supported by bearings fitted in bearing brackets 2a and 2b, and a rotor 6 disposed inside the stator core 3 is prevented from rotating. This rotor 6 includes a secondary conductor bar (not shown),
An end ring 7 and cooling fans 8a and 8b arranged outside the end ring 7 are provided. The cooling fans 8a, 8b are composed of a plurality of blades 8c arranged radially around the rotating shaft 5, as schematically shown in FIG. Reference numeral 9 denotes a fan guide, which is a disc-shaped plate material with a concave center provided with a through hole 9a, and the through hole 9a is disposed toward the tip of the vane blade 8c.

Now, when the open type electric motor configured as described above starts operating, the air holes 10a,
The outside air sucked in through the ventilation hole 9a is guided to the ventilation path 1b side along the fan guide 9, and
b and is discharged from the air hole 10b. At this time, the cooling air flows to the end of the coil 4 (coil end) 4
a and the back side of the stator 3 are mainly cooled. At this time, the cooling air flowing out from the ventilation passage 1b toward the bearing bracket 2b is considerably relaxed, and furthermore,
The cooling fan 8b spreads into the space inside the bearing bracket 2b and prevents the intake of fresh outside air due to the rotation of the cooling fan 8b.
The end portion 4b of the coil 4 is cooled by stirring the loose air flowing out from the coil 4, making it difficult to cool the end portion 4b of the coil 4.

To solve this problem, the cooling fan 8b is made larger,
It is conceivable to increase the capacity of this, but this would increase the wind noise of the cooling fan 8b and increase the noise of the electric motor. Furthermore, by increasing the size of the cooling fan 8b, the windage loss of the electric motor increases and the efficiency also decreases.

Improving the cooling effect has traditionally been an important issue in open type motors like this, but recently, reducing noise has become another important issue. . This can be achieved by reducing the diameter of the cooling fan, which reduces noise.
If the diameter of the cooling fan is simply made smaller, the amount of cooling air will be insufficient and the temperature inside the machine will rise. Therefore, Japanese Utility Model Application Publication No. 40402/1983 proposes a blade shape that causes less reduction in air volume even when the diameter of the cooling fan is reduced.

The inventors of the present invention have repeated numerous trial productions and experiments, and as a result, have been able to provide a cooling structure with even more excellent characteristics.

That is, the present invention has a housing 1, bearing brackets 2a and 2b, a stator 3, a rotor 6, a coil 4, and a cooling fan 11. The stator 3 has an open end, the bearing brackets 2a and 2b are fixed to the open end of the bracket 1, and have air holes 10a and 10b, and the stator 3 has a cylindrical shape. The outer peripheral surface of the rotor 6 is fitted and fixed to the inner peripheral surface of the housing 1, and the rotor 6 has end rings on both end surfaces, and is connected to the inside of the stator 3 through a gap. and is rotatably supported by the bearing brackets 2a and 2b so as to be able to rotate about the central axis of the stator 3, and the coil 4 is wound around the stator 3. can be,
The coil ends 4a and 4b at both ends of the stator 3 protrude in the axial direction of the stator 3 from both end surfaces of the stator 3, and the rotor 6 is arranged in one direction around the center axis of the stator 3. The cooling fan 11 is provided with power so as to be energized only in the rotational direction F, and the cooling fan 11 is located on both end faces of the rotor 6 and is each composed of a large number of blades 11a, and the blade blades is on the circumference from the end ring 7 to the center axis of the stator 3,
It extends in a direction parallel to the central axis and is located in a cavity surrounded by the coil ends 4a and 4b, respectively, and the air hole 10a is opened by the rotation of the cooling fan 11.
In a one-way rotating electric machine configured to take outside air into the housing 1, each of the vane blades 11a is cut in a plane perpendicular to the rotational axis of the rotor 6. (a) The inner end 11b of the rotor 6 viewed in the radial direction from the rotation axis is further advanced in the rotation direction F of the rotor 6 than the outer end 11c, (b) It is curved so as to protrude in a direction opposite to the rotational direction F, and (c) the front surface 11e and the rear surface 11f as seen in the rotational direction F.
At each point, a tangent line 20, 21 in a plane perpendicular to the axis of rotation, and a line 2 extending radially from the axis of rotation and passing through each point.
2 and 23 form a curved shape so that the angles α1 and α2 formed by the inner end 11b and the outer end 11c gradually become smaller.

Hereinafter, basic embodiments of the present invention will be explained with reference to FIGS. 3 to 5. FIG. 3 shows an open drip-proof electric motor (hereinafter referred to as electric motor). Those indicated by the same reference numbers as those of the conventional example already explained have the same structure and have the same function, so the explanation will be omitted.

Cooling fans 11 are arranged on both end faces of the rotor 6, and are composed of a large number of blades 11a each having an arcuate cross section.

The shape of each blade blade 11a cut along a plane perpendicular to the rotational axis of the rotor 6 is as follows: (a) When viewed from the rotational axis of the rotor 6 in the radial direction, the inner end 11b is the outer end 11c. (b) It is curved so as to protrude in the opposite direction to the rotation direction F, (c) The front surface 11e and the rear surface as seen in the rotation direction F. 11f
At each point, a tangent line 20, 21 in a plane perpendicular to the axis of rotation, and a line 2 extending radially from the axis of rotation and passing through each point.
It has a curved shape such that angles α1 and α2 formed by the inner end 11b and the outer end 11c gradually become smaller as they approach the outer end 11c from the inner end 11b.

The diameter r ₁ of the outlet end 11c of this vane blade 11a
is configured to be smaller than the outer diameter r ₀ of the rotor 6. Each of the vane blades 11a can be molded at the same time as the rotor 6, the secondary conductor bar, and its end ring 7 are die-cast. 12 is a fan guide arranged between the bearing brackets 2a, 2b and the coil 4 or the cooling fan 11;
The fan guide 12 is fixed at its outer periphery between the housing 1 and the pilot surfaces of the bearing brackets 2a and 2b, and its center is recessed toward the cooling fan 11 to provide a through hole 12a.

Further, the opening ends of the through holes 12a of this fan guide 12 are respectively connected to the tips 11d of the vane blades 11a.
Place it towards.

The electric motor configured in this way is operated, and the rotor 6
When the fan guide 12 is rotated in the F direction, the outside air sucked in through the air holes 10a, 10b opened in the lower half of the bearing brackets 2a, 2b by the action of the cooling fan 11 flows through the through holes 12a, 12a along the outer surface of the fan guide 12.
After passing through the through holes 12a, 12a, it is discharged to the coil ends 4a, 4b. The cooling air discharged to the coil ends 4a, 4b cools the coil ends 4a, 4b, and then is guided along the inner surfaces of the fan guides 12, 12, and then flows into the housing 1.
It is discharged to the outside of the machine through air holes 1b and 1c made in the lower half of the cylindrical surface on the side of the bearing brackets 2a and 2b. When the cooling fan 11 has such a structure, the ventilation performance of the cooling fan 11 itself improves, so the diameter r ₁ of the cooling fan 11
Sufficient cooling air volume can be obtained even if the Further, by reducing the diameter r ₁ of the cooling fan 11 and using the blade blades 11a having a curved surface, the wind noise of the blades 11a is reduced, and the noise generated therefrom is reduced.

Moreover, the cooling air from the cooling fan 11 is discharged along the extension line of the outlet end 11c of the blade blade 11a, and reaches the wall surface on the inner diameter side of the coil ends 4a, 4b through the shortest air path, 4
Cool b. In addition, it is generally said that when the cooling air is in a turbulent state, separation of the cooling air is less likely to occur and the cooling effect is improved, so if the cooling air is applied from the front of the inner wall of the coil end, the It is thought that the flow (eddy current) component increases, and it is expected that the cooling effect will be improved from this aspect as well.

Note that if the blades 11a are arranged so that the diameter of the cooling fan 11 remains the same as before, a larger air volume can be obtained compared to a cooling fan with a conventional structure, so there is a margin for cooling by this amount, and the heavy load operation of the motor is reduced. Alternatively, it will be possible to respond to overload operations.

Next, a different embodiment of the present invention shown in FIG. 6 will be described. This embodiment shows an electric motor that rotates a rotating shaft 5 in the direction F in the figure. Components denoted by the same reference numerals as those of the previously described embodiments have the same structure, and therefore the description thereof will be omitted. Reference numeral 12 designates a fan guide whose outer periphery is sandwiched and fixed between the end face of the cast housing 1 and the fitting face of the bearing bracket 2a on the anti-load side. is recessed, and a through hole 12a opened in the center is placed with a slight gap from the tip 11d of the vane blade. 17 is a bolt for fixing each bearing bracket 2a, 2b to the end face of the bracket 1, and 1d is a base integrally cast with the housing 1. When the electric motor configured in this way is operated (rotation direction is F),
By the action of the cooling fan 11 on the opposite load side, the cooling air sucked into the machine through the air hole 10a formed in the lower half of the bearing bracket 2a is discharged toward the coil end 4a side. The cooling fan discharged from the cooling fan 11 on the anti-load side to the coil end 4a side is guided to the fan guide 12, and is guided to the ventilation passage 1b on the back side of the stator 3.
sent to. The cooling air sent into the ventilation passage 1b cools the stator and is then discharged to the coil end 4b side. At this time, due to the action of the rib 1a that was cast at the same time as the housing 1, the coil end 4
The cooling air discharged to the b side is rectified to form a laminar flow. The cooling air discharged to the coil end 4b side is further agitated by the action of the cooling fan 11 on the load side, becomes a turbulent flow, and is discharged again to the coil end 4b side. After cooling the coil end 4b, this turbulent cooling air cools the bearing bracket 2b.
It is discharged from the air hole 10b opened in the lower half of the . In this way, by the cooling fan 11 on the load side,
The cooling air discharged in a laminar flow form from the ventilation passage 1b is converted into a turbulent flow with a high cooling effect, and then supplied to the coil end 4b side again, cooled, and then discharged to the outside of the machine. Therefore, both cooling fans 11, 11
The inside of the electric motor is sufficiently cooled by this action.

Since the electric motor embodying the present invention has directionality in its operating direction, it is advantageous when connected to a load that uses rotation in only one direction, such as a pump, fan, or compressor.

In all of the examples above, the case where the present invention was implemented in an open drip-proof electric motor was explained, so the various air holes were concentrated in the lower half of the rotating shaft, but of course the air holes were provided above the rotating shaft. It is also possible to provide one. Furthermore, in the embodiment, a case has been described in which the cooling fan is die-cast integrally with the end ring of the rotor, but of course the cooling fan is manufactured separately from a steel plate or other die-casting process, and the cooling fan is manufactured separately from both end rings of the rotor. Alternatively, they can be assembled on the rotating shafts on both end faces.

As is clear from the above explanation, according to the rotating electrical machine equipped with the cooling fan having the shape of the present invention, various cooling performances of the rotating electrical machine can be improved by improving the aerodynamic performance of the cooling fan. .

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining the structure of a conventional electric motor, FIG. 2 is a schematic diagram for explaining the structure of a cooling fan of a conventional electric motor, and FIG. 3 is a structure of one embodiment of the present invention. FIG. 4 is a cross-sectional view for explaining the essential parts of one embodiment of the present invention, and FIG. 5 is a partial cross-sectional view of the rotor seen from the axial direction for explaining the structure of the cooling fan. FIG. 6 is a partial sectional view for explaining the structure of a different embodiment of the present invention. 1...Housing, 2a, 2b...Bearing bracket, 3...Stator, 4...Coil, 4a, 4b
... Coil end, 6 ... Stator, 7 ... End ring, 10a, 10b ... Air hole, 11 ... Cooling fan, 11a ... Vane blade, 11b ... Inlet end of vane blade, 11c ... Vane blade Outlet end of, 11e...Front surface of vane blade, 11f...
Back side of the vane blade, α ₁ ... Angle between the tangent to the front side of the vane blade and a line extending in the radial direction from the rotation axis of the rotor, α ₂ ... Tangent to the back side of the vane blade and rotation of the rotor The angle formed by a line extending in the radial direction from the axis.

Claims (1)

[Claims] 1. Housing 1 and bearing brackets 2a, 2b
, a stator 3, a rotor 6, a coil 4, and a cooling fan 11; the housing 1 has a cylindrical shape and has open ends at both ends; and the bearing bracket 2a. , 2b are respectively fixed to the open end of the housing 1 and have air holes 10a and 10b. The rotor 6 has end rings 7 on both end faces thereof, and is disposed inside the stator 3 with a gap therebetween, and the bearing bracket 2a ,2
b, the stator 3 is rotatably supported so as to be able to rotate about the central axis of the stator 3; the coil 4 is wound around the stator 3;
The coil ends 4a and 4b at both ends of the stator 3 protrude in the axial direction of the stator 3 from both end surfaces of the stator 3, and the rotor 6 is arranged in one direction around the center axis of the stator 3. The cooling fan 11 is provided with power so as to be biased only in the rotational direction F, and the cooling fan 11 is located on both end faces of the rotor 6, and is each composed of a large number of blades 11a, The blade extends from the end ring 7 on a circumference centered on the central axis of the stator 3,
It extends in a direction parallel to the central axis and is located in a cavity surrounded by the coil ends 4a and 4b, respectively, and the air hole 10a is opened by the rotation of the cooling fan 11.
In a one-way rotating electrical machine configured to take outside air into the housing 1, each of the vane blades 11a has a plane perpendicular to the rotational axis of the rotor 6. The cut cross-sectional shape 11g has the following shapes: (a) The inner end 11b of the rotor 6 viewed in the radial direction from the rotation axis is further advanced in the rotation direction F of the rotor 6 than the outer end 11c, (b) are curved so as to protrude in the opposite direction to the rotational direction F; (c) the front surface 11e and the rear surface 11 as seen in the rotational direction F;
At each point f, angles α1 and α2 formed by tangents 20 and 21 in a plane perpendicular to the axis of rotation and lines 22 and 23 extending radially from the axis of rotation and passing through each point; has a curved shape that gradually becomes smaller as it approaches the outer end 11c from the inner end 11b.