JPS6238939B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric blower, and relates to a stator core shape that increases the air passage cross-sectional area of a core cooling air passage of an electric blower used, for example, in a vacuum cleaner.

[Conventional technology]

In general, an electric blower used for a vacuum cleaner, etc. consists of a drive motor section consisting of a rotor and a stator, a cooling air guide tube into which the drive motor section fits, and a fan.The fan is rotated by the drive motor section. The stator is cooled by passing the intake and exhaust airflow generated by the stator through a core cooling air path formed by the stator and the cooling air guide tube.

Therefore, if the core cooling air passage is narrow compared to the air volume Q of the electric blower at the maximum suction power of the vacuum cleaner, which is around 1.2 m ³ /mm, it becomes difficult for the cooling air to pass through the core cooling air passage, and the stator The turbulent flow occurs in front, creating a positive pressure rise, which reduces the negative pressure rise of the electric blower, thus reducing the negative pressure rise of the vacuum cleaner, and reducing the maximum suction power of the vacuum cleaner. .

Furthermore, as described in Japanese Patent Application Laid-open No. 51-38002, a stator composed of a substantially circular stator core is fitted into a cylindrical outer frame, and a stator is formed protruding from the inner periphery of this outer frame. A structure is known in which the stator is held by a plurality of ribs, and a core cooling air passage partitioned by the ribs is formed between the outer frame and the stator.

[Problem that the invention seeks to solve]

However, in the conventional configuration shown in FIG. 6, the stator core 1 is approximately circular, so the length l ₁ of the fitting contact portion between the outer peripheral edge of the stator core 1 and the cooling air guide tube 2 is long, and the core The cooling air passages 3 and 4 become narrower, and the core cooling air passages 3 formed by each side of the outer periphery of the stator core 1 and the cooling air guide tube 2 are not equal, which causes turbulent flow and reduces the core cooling. There were drawbacks such as the fact that air path 3 was not used effectively.

Furthermore, even if the stator can be cooled uniformly with the structure shown in Japanese Patent Application Laid-Open No. 51-38002, the contact length between the stator core and the fitting contact portion of the cooling air guide tube is large relative to the size of the stator core. There is no explanation regarding the ratio of It became large, and there was a problem with the overall size.

The present invention was developed in view of the above problems, and the stator core is designed to have a substantially square shape so that it is possible to obtain a large amount of air volume, and to reduce the volume of air to increase fan efficiency, and to evenly and reliably cool the drive motor part. year,
By reducing the outer diameter of the rotor core, the core can be formed using less material, and with the simple structure of the stator core, the cross-sectional area of each cooling air passage between the stator and the cooling air guide tube can be made equal. It is an object of the present invention to provide an electric blower which can maximize the air passage cross-sectional area of the core cooling air passage and has good fan efficiency.

[Means for solving problems]

The electric blower of the present invention includes a drive motor section including a rotor and a stator, a fan that is rotated by the rotation of the rotor of the drive motor section, and a fan that surrounds the stator of the drive motor section and that rotates the fan. and a cylindrical cooling air guide tube forming a core cooling air passage for an airflow generated by the stator to cool the stator, the stator core constituting the stator having an approximately square outer shape, The ratio of the length of the fitting contact portion between the stator core and the cooling air guide tube to the outer diameter of the stator core is 0.12 or less, and each outer peripheral edge of the stator and the inner circumferential surface of the cooling air guide tube are The cooling air passages are characterized by having equal air passage cross-sectional areas.

[Effect]

In the electric blower of the present invention, the fan provided on the rotating shaft is rotated by the rotation of the rotor of the drive motor section, and the air flow taken in by this fan flows into the drive motor section. The air passes through a core cooling air path made up of a stator and a cooling air guide tube, and a core cooling air path made up of a rotor and stator, and is discharged from the exhaust hole of the cooling air guide tube. .

At this time, since the outer shape of the stator core is approximately square,
The core cooling air passage made up of the stator and the cooling air guide tube becomes wider, and the cross-sectional area of each core cooling air passage becomes the same, so that the cooling air passing through this core cooling air passage is distributed to each core cooling air passage. Flows uniformly, turbulence is less likely to occur, pressure loss due to turbulence is reduced, and cooling efficiency is increased. If the length of the fitting contact between the stator core and the cooling air guide tube is long, the core cooling air passage cross-sectional area will be significantly reduced, pressure loss will increase, and fan efficiency will decrease. When the length, that is, the ratio of the length of the fitting contact part to the outer diameter of the stator core, is 0.12 or less, the fan efficiency ηf becomes almost constant at 60% or more, which is lower than the conventional fan efficiency ηf ₁ of about 57%.
Improved. Furthermore, the electric blower as a whole can be made smaller compared to the size of the stator core, thereby improving economic efficiency.

〔Example〕

Next, the configuration of an embodiment of the present invention is shown in FIGS. 1 to 5.
The diagram will be explained.

Reference numeral 11 denotes an electric blower main body, and this electric blower main body 11 is composed of a drive motor section 12 and a fan section 13.

This drive motor section 12 has a stator 14 in which a field coil 41 is wound around a stator core 33 that is laminated and fixed, and a rotor 15 surrounded by the stator 14.
A cooling air guide cylinder 16 having a circular cross section is fitted onto the outer periphery of the stator 14 . Brush supports 17 located below the stator 14 and provided on both sides of the cooling air guide tube 16 are provided with brushes 18 biased by springs 32 so as to protrude inward. A commutator 19 is provided on the rotating shaft 20 of the rotor 15 with the brush 18 pressed against it. One end of this rotating shaft 20 is rotatably supported by a bearing 31 provided in the cooling air guide tube 16. Further, the opening surface of the cooling air guide tube 16 is connected to the partition frame 2.
A bearing portion 22 is formed in the center of the partition frame 21, and a bearing 31 for pivotally supporting the rotating shaft 20 is provided in the bearing portion 22. A plurality of ventilation holes 23 are formed in the partition frame 21 at the outer periphery of the bearing portion 22 .

The fan part 13 is located outside the partition frame 21, and includes a fan 24 fixed to the end of the rotating shaft 20 protruding from the partition frame 21 with a nut 20a, and a fan 24 located inside the fan 24. A rectifier plate 26 with a rectifier hole 25 formed on the outside, and an air intake hole 27 in the center that covers the rectifier plate 26 and the fan 24.
The fan cover 28 has an open side and a peripheral edge attached to the partition frame 21.

As shown in FIG. 2, the stator core 33 of the stator 14 of the drive motor section 12 has an approximately square outer shape, and the area of the core cooling air passage 34 consisting of the stator 14 and the cooling air guide tube 16 is At the same time, the length l of the fitting contact portion between the stator core 33 and the cooling air guide tube 16 is shortened, and the outer diameter D _s of the stator core 33 is 82 mm, that is, the inner diameter of the cooling air guide tube 16 is 82 mm, and the ratio l/D _s of the length l of the fitting contact portion to the outer diameter D _s of this stator core 33 is 0.12.
It is formed as follows.

35 is a rotor core of the rotor 15, and as shown in FIGS. 3 to 5, a plurality of teeth portions 36 are provided.
A slot portion 38 is formed between each tooth portion 36 and around which a coil (not shown) _is wound. Ratio D _r /D _s to D _s
is formed to be 0.44 to 0.53, and furthermore, the sum of the width _bt of the teeth of the rotor core 35 facing the polar arc angle θ of the stator core 33 is the value of the width bt of both the left and right yokes of the stator core 33. It is formed so that it is approximately equal to or larger than the sum of the 37 yoke widths b _y .

Further, the ratio of the total slot area S _as of the rotor core 35 to the outer diameter product D _r ² of the rotor core 35 is 0.23 or less.

Next, the operation of this embodiment will be explained.

As the rotor 15 of the drive motor section 12 rotates, a fan 24 provided on the rotating shaft 20 is rotated, and air is taken in from the intake hole 27 of the fan cover 28 by the fan 24. As shown by the arrow in FIG. 1, the air is rectified by the rectifier plate 26 and blown to the drive motor section 12 from the ventilation hole 23 of the partition frame 21.

The airflow that has flowed into the drive motor section 12 is directed to a core cooling air path 34 made up of the stator 14 and the cooling air guide cylinder 16, and a core cooling air path made up of the rotor 15 and the stator 14. 40 and is discharged from a discharge hole (not shown) of the cooling air guide tube 16.

At this time, since the outer shape of the stator core 33 is made approximately square, the core cooling air passage 34 composed of the stator 14 and the cooling air guide tube 16 becomes wider as shown in FIG. The cross-sectional areas of the air passages 34 are the same, and the cooling air passing through the core cooling air passages 34 flows uniformly in each core cooling air passage 34, making it difficult for turbulence to occur, reducing pressure loss due to turbulence, and improving cooling. Efficiency increases.

Next, FIG. 7 shows the measurement results of the fan efficiency η _f with respect to the external shape of the stator core 33.

Generally, the electric blower air volume Q at the maximum suction power of a vacuum cleaner is approximately 1.2 m ³ /min, so the electric blower air volume Q is kept constant at approximately 1.2 m ³ /min, and the outer diameter D _s of the stator core 33 is 82 mm. The experiment was conducted by keeping the length l of the fitting contact portion between the stator core 33 and the cooling air guide tube 16 constant and varying it to 3 mm, 6 mm, 9 mm, 14 mm, and 17 mm.

As can be seen from Fig. 7, the length l of the mating contact part is
If it is 10 mm or more, the core cooling air passage cross-sectional area will decrease significantly, pressure loss will increase, and fan efficiency will decrease.
When the length l of the fitting contact portion is 10 mm or less, that is, the ratio l/D _s of the length l of the fitting contact portion to the outer diameter D _s of the stator core is 0.12 or less, the fan efficiency η _f is approximately 60% or more. The fan efficiency η f1 is constant, which is improved from the conventional fan efficiency η _f1 of about 57%.

In addition, since the outer shape of the stator core 33 is approximately square, the area of the material of the stator core 33 is a ₁ × b ₁ in the conventional case, as shown in FIGS. 2 and 6.
a×b (however, a ₁ > a, b ₁ > b), and the material of the stator core 33 is 20% or more.
The weight can be reduced by more than 10%, improving economic efficiency. Note that this stator core 33 has a reduced pole width b _p and a coil 41 wound around the stator 14.
The length per turn is shortened, the area of the slot 42 of the stator core 33 is reduced, the wire diameter of the coil 41 is made thinner, the weight of the coil 41 is reduced, and the stator 14 is made smaller.
Reduces weight.

Next, the outer shape is approximately square, and the outer diameter D _s is 82 mm.
The cooling air guide tube 16 for the stator core 33
The electric blower efficiency η with respect to the change in the shape of the rotor core 35 was measured in an electric blower using the stator core 33 in which the ratio of the length l of the fitting contact portion with the stator core 33 was set to 0.12 or less.

In addition, when changing the shape of the rotor core 35, in order to know the limit value of the current density of the stator 14 and rotor 15, the current of the rotor and stator is calculated using the conventional stator core and rotor core. FIG. 8 shows the rotor coil and stator coil temperatures, motor efficiency η _n1 and electric blower efficiency η ₁ when the density is increased at the same rate. Note that the electric blower output (or drive unit shaft output) at this time is constant.

As can be seen from Fig. 8, when the current density is increased, the temperature of the rotor coil and stator coil also rises, the motor efficiency η _n1 decreases, and the electric blower efficiency η ₁ also decreases, so the current density is increased to 35A/ mm ² or less to prevent the temperature of the rotor coil and stator coil from rising too much.

In addition, the relationship between the outer diameter _Dr of the rotor core 35 and the area S _as of the slot portion 38 of the rotor core 35 was calculated by changing the width b _t and length l _t of the teeth portion 36. It is shown in FIG. Note that each value of the rotor 14 at this time is as follows. Slot opening width b ₁ is 1.6 mm, tooth end thickness t ₁ is 1.2 mm, number of slots η _s is 22, number of coil turns W _a is 11 turns, armature current I _a is 2.79 A, maximum space factor SF _nax
is 0.26, and a in the figure is when the teeth width b _t is 1.6 mm and the teeth length l _t is 7.5 mm, and b is when the teeth width b _t is 1.75 mm and the teeth length l _t is 8.5 mm. , C is a graph diagram when the teeth width b _t is 1.75 mm and the teeth length l _t is 7.5 mm.

As can be seen from Fig. 9, the slot area S
Since the current density is determined by _as , the current density is
To make it ^less than 35A/mm2, the slot area S _as is 111.5
mm ² or more, and the outer diameter D _r of the rotor core 35 must be 32 mm or more.

Therefore, the outer diameter D _r of the rotor core 35 is 34 mm, 36
mm, 38mm, 39mm, 40mm, 43.3mm, 45mm,
This rotor 15 is combined with the stator 13 formed by the rectangular stator core 33 with an outer diameter D _s of 82 mm to obtain fan efficiency η _f , motor efficiency η _n , electric blower efficiency η, rotor core 35 and coil The results of measuring the weight m of 44 are shown in FIG. At this time, the teeth width b _t is set so that each efficiency is not affected by changes in the iron loss of the teeth portion 36, which generates nearly 70% of the iron loss of the stator 14 and rotor 15.
and teeth length l _t are kept constant so that the iron loss does not change.

As can be seen from FIG. 10, the motor efficiency η _n increases when the outer diameter D _r of the rotor core 35 is reduced.
The wire diameter of the coil 5 (not shown) becomes smaller, and the copper loss increases in proportion to the square of the current density.However, since the rotor 15 is reduced in size, the mechanical loss is increased outside the rotor core 35. Since the outer diameter D _r decreases in almost inverse proportion to the diameter D r , it decreases rapidly when the outer diameter D _r becomes 38 mm or less.

Furthermore, when the outer diameter D _r of the rotor core 35 is reduced, the area of the core cooling air passage 40 becomes larger, and the positive pressure rise due to turbulent flow of cooling air is reduced, and the fan efficiency η _f is determined by the rotation of the rotor 15. The turbulence caused by this decreases as well, so it increases.

Therefore, the electric blower efficiency η is the motor efficiency η
Since it is expressed as the product of _n and fan efficiency η _f , when the outer diameter D _r of the rotor core 35 is 36 mm to 43.3 mm, that is, the outer diameter D _r of the rotor core ₃₅ is When the ratio D _r /D _s is 0.44 to 0.53, the electric blower efficiency η is 37 compared to the conventional electric blower efficiency η ₁ .
%, it is more than 37%, which improves the efficiency of the conventional electric blower η ₁ , and the rotor core 3
The outer diameter D _r of the rotor core 35 is 38 mm, that is, the ratio of the outer diameter of the rotor core 35 to the outer diameter D _s of the stator core 33 is D _r /
When D _s is 0.46, the efficiency of the electric blower is approximately 40%, which is the maximum.

Note that the weight m of the rotor core 35 and the coil (not shown) can be reduced as the outer diameter D _r of the rotor core 35 is smaller, and the weight can be reduced.

In the above embodiment, the outer diameter D _s of the stator core 33 was fixed at 82 mm, but the same result can be obtained with other outer diameters.

Next, when the stator core 33 has a substantially square shape, the outer diameter D _s is 82 mm, and the outer diameter D _r of the rotor core 35 is constant at 38 mm, the teeth portion 36 has nearly 70% of the iron loss. Reduce iron loss. On this occasion,
It is conceivable to widen the teeth width b _t and shorten the teeth length l _t , but by widening the teeth width b _t and shortening the teeth length l _t , the slot area S _as decreases, and the rotor 15 The wire diameter of the coil (not shown) must be made thinner,
Copper loss increases by reducing the wire diameter of the coil, so it is not possible to simply widen the teeth width b _t and shorten the teeth length l _t , so the teeth width b _t and teeth length l _t are changed. By this, the slot area S _as is changed, and this slot area S
FIG. 11 shows the results of examining changes in motor efficiency η _n with respect to changes in _as . As can be seen from Fig. 11, the copper loss of the rotor 15 can be reduced by reducing the slot area _{S as} at least within the range of 14.7 mm to 16.1 mm (shown in parentheses in Fig. 11). Since the decrease in iron loss is larger than the increase, the motor efficiency η _n increases, especially when the slot area S _as is 15.3 mm3 ^or more, that is, the rotor core 35
When the ratio S _as /D _r ² of the total slot area S _as of the rotor core 35 to the outer diameter product D _r ² is 0.23 or less,
Motor efficiency η _n increases significantly. This means that the sum of the teeth width S _as of the rotor core 35 facing the polar arc angle θ of the stator core 33 is the width b of both yokes of the stator 13.
Since the width of both yokes b is approximately equal to _y or wider than _y , the magnetic path can be used effectively without waste.

In the above embodiment, the outer diameter of the rotor 33 was set to 38 mm, but similar results can be obtained even if rotor cores 35 having other outer diameters are used.

Note that as in the configuration of the above embodiment, the stator core 33
The ratio of the outer diameter of the rotor core 35 to the outer diameter of
By setting it to 0.44 to 0.53, the outer diameter of the rotor core 35 can be reduced, the material of the rotor core 35 and the weight of the rotor core 35 can be reduced, economical efficiency can be improved, and motor efficiency can be improved by reducing the rotor 15. The increase in fan efficiency due to the expansion of the core cooling air passage 34 is greater than the decrease in the amount of air, and the efficiency of the electric blower can be improved.

Further, the total teeth width of the rotor core 35 facing the polar arc angle of the stator core 33 is approximately equal to or wider than both yoke widths of the stator core 33 and is relative to the outer diameter area of the rotor core 35. By setting the ratio of the total slot area of the rotor 15 to 0.23 or less, the wire diameter of the coil wound around the rotor can be made thinner and the weight of the coil can be reduced, and copper loss can be increased due to the thinner wire diameter of this coil. Rotor 15 due to wider teeth width and shorter teeth length compared to
It is possible to reduce iron loss in the teeth portion of the coil, and further, by reducing the wire diameter of the coil, the weight of the coil can be reduced, and the weight of the rotor 15 and the weight of the electric blower can be reduced.

〔Effect of the invention〕

According to the present invention, the outer shape of the stator core is approximately square, and the area of each core cooling air passage made up of the stator and the cooling air guide tube is made equal, so that turbulence is less likely to occur and windage loss is reduced. The ratio of the length of the fitting contact part between the stator core and the cooling air guide tube to the outer diameter of the stator core is 0.12. By setting the following, the cooling air passage area can be widened, the pressure loss inside the drive motor can be reduced, the negative pressure rise in the fan can be increased, and the fan efficiency can be further improved.
Furthermore, since the stator core has a substantially square shape, the area of each core cooling air passage between the stator and the cooling air guide tube can be equalized and maximized with a simple structure, and the material used for the stator core can be reduced. In addition to improving economic efficiency, the weight of the stator core can also be reduced, and the weight of the electric blower as a whole can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the electric blower of the present invention, FIG. 2 is a plan sectional view showing the stator core fitted in the cooling air guide tube, and FIGS. 3 and 4 are A plan view showing changes in the core cooling air passage area due to changes in the outer diameter of the rotor core, Figure 5 is a plan view of the rotor core, and Figure 6 shows a conventional stator core fitted into the cooling air guide tube. Figure 7 is a characteristic diagram of fan efficiency versus the ratio of the stator core outer diameter to the length of the fitted part, and Figure 8 is a graph showing the temperature of the stator and rotor versus current density and the motor. A characteristic diagram of efficiency and electric blowing efficiency. Figure 9 is a characteristic diagram of the rotor slot area with respect to the rotor core outer diameter. Figure 10 is a characteristic diagram of the motor efficiency with respect to the ratio of the rotor core outer diameter to the stator core outer diameter. FIG. 11 is a characteristic diagram of efficiency, electric blower efficiency, and weight of the rotor core and coil; FIG. 11 is a characteristic diagram of motor efficiency with respect to the ratio of the slot area to the outer diameter product of the rotor core. 12... Drive motor section, 14... Stator, 15
... Rotor, 16 ... Cooling air guide tube, 33 ... Stator core, 34 ... Core cooling air passage, 35 ... Rotor core, D _s ... Outer diameter of stator core 33, _Dr ... …
Outer diameter of rotor core 35, l... Length of fitting contact portion, b _t ... Teeth width, b _y ... Yoke width, S _as
...Slot area, θ...Polar arc angle.

Claims (1)

[Claims] 1. A drive motor section consisting of a rotor and a stator, a fan that is rotated by the rotation of the rotor of the drive motor section, and a fan that surrounds the stator of the drive motor section and that is generated by the rotation of the fan. a cylindrical cooling air guide tube forming a core cooling air passage for airflow that cools the stator; The ratio of the length of the fitting contact portion between the stator core and the cooling air guide tube to the diameter is set to 0.12 or less, and each of the stator cores and the cooling air guide tube is made up of an outer circumferential edge of the stator and an inner circumferential surface of the cooling air guide tube. An electric blower characterized in that the cross-sectional areas of the cooling air passages are made equal.