WO2009084245A1

WO2009084245A1 - Electric motor for compressor, compressor, and freezing cycle device

Info

Publication number: WO2009084245A1
Application number: PCT/JP2008/053235
Authority: WO
Inventors: Takahiro Tsutsumi; Tomoaki Oikawa; Osamu Kazama; Tsuneyoshi Tajima; Sadami Okugawa; Hayato Yoshino; Koji Yabe
Original assignee: Mitsubishi Electric Corporation
Priority date: 2007-12-27
Filing date: 2008-02-26
Publication date: 2009-07-09
Also published as: CN101821925A; JPWO2009084245A1

Abstract

An object is to provide an electric motor for a compressor starting torque for which can be increased with the rise of the price of a component and a deterioration in efficiency in operation suppressed. The electric motor for the compressor is housed with a compressor element for compressing a cooling medium in an airtight container and connected to the compressor element via a driving axis to drive the compressor element. The electric motor for the compressor comprises a stator fixed to the inner periphery portion of the airtight container, a rotator (11) which is provided on the inner side of the stator and which has a rotator core (11a), and a double squirrel-cage conductor which is cast in the rotator core (11a) and which is constituted by a secondary conductor comprising an outer layer secondary conductor and an inner layer secondary conductor and an end ring (32). In the rotator core (11a), an air hole (33) which is the passage of the cooling medium is provided. The inner diameter side of the end ring (32) is enlarged to a driving axis side in such a manner that the air hole (33) is sealed. The end ring (32) has a cutting (34) for allowing the air hole (33) to be communicated with the space of the airtight container so as not to seal the air hole (33).

Description

Electric motor for compressor, compressor and refrigeration cycle apparatus

The present invention relates to an electric motor for a compressor, a compressor, and a refrigeration cycle apparatus.

In a compressor used in a refrigerating and air-conditioning apparatus such as an air conditioner, a brushless DC motor, an induction motor, or the like is used as an electric motor that drives a compression mechanism. In induction motors, ordinary cage induction motors (single cage type) are mainly used.

Induction motors include three-phase induction motors and single-phase induction motors. When an induction motor is used for the compressor, the three-phase induction motor has a large start torque, so there are few problems regarding the start. However, in a single-phase induction motor, a sufficient starting torque is not obtained only by an operating capacitor connected to the outside. Therefore, a starting capacitor may be added in addition to the driving capacitor (see, for example, Patent Document 1).

Also, the phase difference between the main winding and the auxiliary winding wound around the stator of the single-phase induction motor is shifted from 90 ° (electrical angle).

Furthermore, the secondary resistance of the rotor is increased to increase the starting torque.
JP-A-6-213167

However, the method of adding a starting capacitor as in the above-mentioned Patent Document 1 has a problem that the part price is high because a switch for opening and closing the starting capacitor is also required.

Also, there is a problem that the method of shifting the phase difference between the main winding and the auxiliary winding from 90 ° (electrical angle) cannot be realized depending on the number of slots of the stator core.

Furthermore, the method of increasing the starting torque by increasing the secondary resistance of the rotor has a problem that the efficiency during operation of the single-phase induction motor decreases.

The present invention has been made to solve the above-described problems. An electric motor for a compressor, a compressor, and a refrigeration cycle capable of increasing a starting torque while suppressing a rise in parts price and a decrease in efficiency during operation. An object is to provide an apparatus.

An electric motor for a compressor according to the present invention is housed together with a compression element that compresses a refrigerant in an airtight container, and is connected to the compression element by a drive shaft to drive the compression element.
A stator fixed to the inner periphery of the sealed container;
A rotor provided inside the stator and having a rotor core;
A double squirrel-cage conductor composed of an outer ring secondary conductor and an inner layer secondary conductor and an end ring, which are cast into the rotor core,
The rotor iron core has air holes that serve as refrigerant passages.
The end ring expands to the drive shaft side so that the inner diameter side closes the air hole,
In order to prevent the air holes from being blocked, an escape portion that communicates the air holes with the space of the sealed container is provided.

The motor for a compressor according to the present invention is characterized in that a relief portion is formed by a notch provided in the inner periphery of the end ring.

The motor for a compressor according to the present invention is characterized in that it is constituted by an end ring air hole having a relief portion provided in the end ring.

An electric motor for a compressor according to the present invention is housed together with a compression element that compresses a refrigerant in an airtight container, and is connected to the compression element by a drive shaft to drive the compression element.
A stator fixed to the inner periphery of the sealed container;
A rotor provided inside the stator and having a rotor core;
A double squirrel-cage conductor composed of an outer ring secondary conductor and an inner layer secondary conductor and an end ring, which are cast into the rotor core,
The stator is provided with a stator air hole that serves as a refrigerant passage,
The inner ring side of the end ring is configured to be positioned in the vicinity of the drive shaft.

In the compressor motor according to the present invention, the stator includes a stator core, a notch is provided in the outer peripheral portion of the stator core, and the stator air hole is provided between the hermetic container and the notch in the outer peripheral portion of the stator core. Is provided.

An electric motor for a compressor according to the present invention is characterized in that the rotor core has a shaft hole for fitting with the drive shaft, and the inner diameter of the end ring is made 8 mm or more larger than the diameter of the shaft hole.

The motor for a compressor according to the present invention is characterized in that the total volume of the end ring is 13% or more of the volume of the rotor core.

In the compressor motor according to the present invention, the compression element includes a bearing, and the compressor motor has a cantilever structure in which the bearing is supported on one side by the bearing of the compression element, and between the stator and the rotor. The length of the gap in the radial direction is as follows.
(1) When the outer diameter of the stator is smaller than 140 mm, the radial length of the gap is 0.6 mm or less;
(2) When the outer diameter of the stator exceeds 140 mm, the radial length of the gap is 0.8 mm or less.

The electric motor for a compressor according to the present invention is characterized in that the outer periphery on the opposite side of the bearing of the compression element of the rotor core is cut so that the outer diameter is smaller than the outer periphery on the bearing side of the compression element of the rotor core. .

A compressor according to the present invention is characterized in that the above-described electric motor for compressor is mounted.

The compressor according to the present invention is characterized by using R22 as a refrigerant.

The compressor according to the present invention is characterized by using R410a as a refrigerant.

The compressor according to the present invention is characterized by using CO ₂ as a refrigerant.

The refrigeration cycle apparatus according to the present invention is characterized in that the compressor, the condenser, the decompression device, and the evaporator are connected by a refrigerant pipe.

The electric motor for a compressor according to the present invention can increase the starting torque while suppressing the rise in the parts price and the decrease in efficiency during operation.

Embodiment 1 FIG.
FIGS. 1 to 14 are diagrams showing Embodiment 1, FIG. 1 is a longitudinal sectional view of a rotary compressor 100, FIG. 2 is a transverse sectional view showing an electric element 13, and FIG. 3 shows a rotor 11 of the electric element 13. 4 is a perspective view showing the rotor 11 of the electric element 13, FIG. 5 is a side view of the rotor 11 provided with a notch 34 in the end ring 32, and FIG. 6 is provided with an end ring air hole 32a. 7 is a side view of the rotor 11, FIG. 7 is a cross-sectional view of the vicinity of the electric element 13 showing an example in which an air hole is provided on the side of the stator 12, FIG. 8 and FIG. The figure which shows the relationship between the volume ratio of the ring 32 and the rotor core 11a, secondary resistance R2, and motor efficiency, FIG. 11 is the fragmentary sectional view of the electrically-driven element 13, FIG. 12 is a single cage shape and a double cage shape FIG. 13 is a diagram showing the torque ripple of the rotor 11 in which a cutting portion is provided on a part of the outer periphery. Side view, FIG. 14 is a configuration diagram of a refrigeration cycle apparatus using the rotary compressor 100.

This embodiment is characterized by the structure of a rotor of an electric motor used for a compressor such as a rotary compressor.

Other than the structure of the rotor of the electric motor in the rotary compressor, it is known. Accordingly, the overall configuration of a one-cylinder rotary compressor (an example of a compressor) will be briefly described with reference to FIG.

As shown in FIG. 1, a rotary compressor 100 (an example of a compressor) houses a compression element 10 and an electric element 13 (referred to as a compressor motor) and refrigerating machine oil (not shown) in a sealed container 4. ing. The refrigerating machine oil is stored at the bottom of the sealed container 4. The refrigerating machine oil mainly lubricates the sliding portion of the compression element 10. The sealed container 4 includes a body 1, an upper dish container 2, and a lower dish container 3.

The compression element 10 includes a cylinder 5, an upper bearing 6 (an example of a bearing), a lower bearing 7 (an example of a bearing), a drive shaft 8, a rolling piston 9, a vane, and the like. The cylinder 5 forms a compression chamber inside. The upper bearing 6 and the lower bearing 7 close the openings at both ends (axial direction) of the cylinder 5. The upper bearing 6 and the lower bearing 7 support a compressive load received by the eccentric portion of the drive shaft 8. The rolling piston 9 is fitted to the eccentric portion of the drive shaft 8. The vane reciprocates in the groove of the cylinder 5, and the tip contacts the rolling piston 9. A compression chamber is formed by the cylinder 5, the rolling piston 9, and the vane.

The electric element 13 includes a stator 12 that is fixed to the body 1 of the sealed container 4 and a rotor 11 that rotates inside the stator 12.

The rotor 11 is a double squirrel-cage rotor made of aluminum die cast, details of which will be described later. The drive shaft 8 is fixed to the inner periphery of the rotor 11.

The lead wire 21 is connected to the winding 20 of the stator 12. The lead wire 21 is connected to the glass terminal 17. The glass terminal 17 is fixed to the sealed container 4 by welding. Electric power is supplied to the glass terminal 17 from an external power source.

The rotary compressor 100 includes a suction muffler 14 outside the sealed container 4. The suction muffler 14 is provided to prevent liquid refrigerant from being directly sucked into the rotary compressor 100. A suction pipe 15 of the suction muffler 14 is connected to the cylinder 5 of the compression element 10. The high-temperature and high-pressure gas refrigerant compressed by the compression element 10 passes through the electric element 13 and is finally discharged from the discharge pipe 16 to the outside.

Here, the basic concept of this embodiment will be described. Assume that a single-phase induction motor is used as the electric element 13 of the rotary compressor 100 for a single-phase AC power supply. The single-phase induction motor is a capacitor motor that uses only a driving capacitor in order to reduce the component price. A capacitor motor has a smaller starting torque than a three-phase induction motor. The starting torque of the capacitor motor is related to the secondary resistance of the rotor 11 (cage rotor). The starting torque of the capacitor motor increases as the secondary resistance of the rotor 11 increases. However, the secondary resistance of the rotor 11 is also related to the efficiency during operation of the capacitor motor. When the secondary resistance of the rotor 11 is large, the efficiency during the operation of the capacitor motor decreases.

When the resistance of the aluminum bar is Rb and the resistance of the end ring is Rr, the secondary resistance R2 of the rotor 11 is
R2 = k1 × (Rb + Rr) (1)
It is represented by Here, k1 is a constant.

When the rotor 11 is an ordinary cage rotor (single cage type), the resistance Rb of the aluminum bar starts with a large slip (relative speed between the rotating magnetic field formed by the winding 20 of the stator 12 and the rotor 11). There is not much difference between when driving and when driving with little slip. When the radial depth of the aluminum bar is long, the resistance Rb during operation is slightly smaller than the resistance Rb during startup.

In consideration of the efficiency during operation, the secondary resistance R2 of the rotor 11 cannot be increased too much. Therefore, the starting torque related to the secondary resistance R2 is relatively small.

Therefore, usually, a starting capacitor is added to increase the starting torque. However, adding a starting capacitor increases the part price.

。 We searched for a method to improve the starting torque without increasing the part price and without reducing the efficiency during operation.

As a result, it was found that the double cage rotor is effective. The double squirrel-cage rotor has the following characteristics.

That is, the double cage rotor has an outer layer slot (a slot provided along the outer periphery of the rotor core) having a large resistance and an inner layer slot (a portion closer to the inner circumference of the rotor core than the outer layer slot) having a small resistance. Provided with a slot provided along the outer layer slot. As a general feature, an induction motor having a double squirrel-cage rotor has a high slip frequency at startup. Therefore, magnetic flux flows on the rotor outer peripheral side. Since the secondary current flows mainly only in the outer layer slot having a high resistance, the starting torque is increased. Also, during normal operation, the slip frequency is low. Therefore, the secondary current flows in both the outer layer slot and the inner layer slot. Accordingly, the secondary resistance is reduced and the secondary copper loss is reduced. Therefore, it has a characteristic that high efficiency can be realized.

An embodiment in the case where the double cage rotor is applied to the rotor 11 of the rotary compressor 100 will be described below.

First, the configuration of the electric element 13 using a single-phase induction motor will be briefly described with reference to FIGS. The electric element 13 includes a stator 12 and a rotor 11 that rotates inside the stator 12.

A stator 12 shown in FIG. 1 is a stator of a two-pole single-phase induction motor. The stator 12 includes a stator core 12a and a main winding 20a and an auxiliary winding 20b inserted into the stator slot 12b. The main winding 20a and the auxiliary winding 20b constitute the winding 20. An insulating material is inserted into the stator slot 12b in order to ensure insulation between the winding 20 and the stator core 12a, but is omitted here. In this example, the number of stator slots 12b is 24. However, this is an example, and the number of slots is not limited to 24.

The stator core 12a is manufactured by punching electromagnetic steel sheets having a thickness of 0.1 to 1.5 mm into a predetermined shape, laminating them in the axial direction, and fixing them by caulking or welding. On the outer peripheral surface of the stator core 12a, there is provided a notch 12c that forms a substantially straight portion obtained by notching the outer peripheral circular shape into a substantially straight line.

When the single-phase induction motor using the stator 12 of FIG. 2 is used for the rotary compressor 100, the stator 12 is shrink-fitted into the cylindrical sealed container 4 of the rotary compressor 100. Therefore, the notch 12 c is necessary to ensure a refrigerant passage between the stator 12 and the sealed container 4.

A concentric winding or lap winding main winding 20a is inserted into the stator slot 12b. A main winding magnetic flux is generated by passing a current through the main winding 20a. Similarly to the main winding 20a, a concentric winding type or overlapping winding type auxiliary winding 20b is inserted into the stator slot 12b. The auxiliary winding magnetic flux is generated by passing a current through the auxiliary winding 20b.

Generally, the angle formed by the main winding magnetic flux and the auxiliary winding magnetic flux is 90 degrees in electrical angle (here, since the number of poles is two, the mechanical angle is also 90 degrees). A main winding is connected in parallel to an operation capacitor (not shown) connected in series with the auxiliary winding 20b. And the both ends are connected to a single phase alternating current power supply. Thereby, a main winding magnetic flux and an auxiliary winding magnetic flux can be generated, and a dipole rotating magnetic field can be generated.

The rotor 11 includes a rotor core 11a and a double squirrel-cage conductor. The double squirrel-cage conductor includes an aluminum bar 30 and an end ring 32. The aluminum bar 30 includes an outer layer aluminum bar 30a (outer layer secondary conductor) cast into the outer layer slot 40a and an inner layer aluminum bar 30b (inner layer secondary conductor) cast into the inner layer slot 40b. The end rings 32 (two pieces) are provided at both axial ends of the rotor 11. The end ring 32 is literally ring-shaped (donut-shaped). The end ring 32 is connected to both ends of each aluminum bar 30 (outer layer aluminum bar 30a, inner layer aluminum bar 30b).

The rotor core 11a is manufactured by punching electromagnetic steel sheets having a thickness of 0.1 to 1.5 mm into a predetermined shape and laminating them in the axial direction in the same manner as the stator core 12a. In general, the rotor core 11a is often punched from the same material as the stator core 12a. However, the materials of the rotor core 11a and the stator core 12a may be changed.

The rotor core 11 a has a double cage rotor slot 40. The rotor slot 40 includes an outer layer slot 40a and an inner layer slot 40b. The outer layer slot 40a is provided on the outer peripheral side in the radial direction. The inner layer slot 40b is provided inside the outer layer slot 40a.

Aluminum, which is a conductive material, is cast into both the outer layer slot 40a and the inner layer slot 40b. Then, the outer layer aluminum bar 30a is cast into the outer layer slot 40a. Further, the inner layer aluminum bar 30b is cast into the inner layer slot 40b. A squirrel-cage secondary winding is formed together with the outer aluminum bar 30a and the inner aluminum bar 30b and the end rings 32 provided on both end surfaces of the rotor 11 in the stacking direction. Generally, the aluminum bar 30 and the end ring 32 are manufactured by casting aluminum simultaneously by die casting.

In FIG. 2, the outer layer slot 40a and the inner layer slot 40b constituting the double cage shape are separated by an inner peripheral thin wall (thin wall portion provided between the outer layer slot 40a and the inner layer slot 40b) made of a magnetic steel sheet. The outer layer aluminum bar 30 a inside the outer layer slot 40 a and the inner layer aluminum bar 30 b inside the inner layer slot 40 b are electrically connected by an end ring 32.

As already described, in the electric element 13 (single phase induction motor) using the double squirrel-cage rotor, a current flows through the outer aluminum bar 30a at the time of startup. Almost no current flows through the inner aluminum bar 30b. Therefore, the resistance Rb of the aluminum bar 30 is increased, and the secondary resistance R2 is increased. The secondary resistance R2 is proportional to the sum of the resistance Rb of the aluminum bar 30 and the resistance Rr of the end ring 32 as shown in the equation (1). The secondary resistance R2 necessary for producing the required starting torque can be earned by the resistance Rb of the aluminum bar 30. Therefore, the resistance Rr of the end ring 32 may be small.

In order to increase the efficiency during operation of the electric element 13 (single phase induction motor), the secondary resistance R2 should be small. During the operation of the electric element 13 (single phase induction motor), a current also flows through the inner layer aluminum bar 30b for the reasons described above. Accordingly, the area of the aluminum bar 30 increases, and the resistance Rb of the aluminum bar 30 becomes smaller during operation than during startup.

If the resistance Rr of the end ring 32 is small, the secondary resistance R2 is further reduced.

When a normal cage rotor (single cage) is used for the electric element 13, the resistance Rb of the aluminum bar 30 does not change much between startup and operation. Therefore, the resistance Rr of the end ring 32 cannot be made too small in order to produce the required starting torque.

By using a double squirrel-cage rotor for the electric element 13, the secondary resistance R2 required for producing the required starting torque can be earned by the resistance Rb of the aluminum bar 30. Therefore, the resistance Rr of the end ring 32 can be reduced to increase the efficiency during operation.

In order to reduce the resistance Rr of the end ring 32, the volume of the end ring 32 is increased. When the volume of the end ring 32 is increased, it is difficult to extend the outer periphery of the end ring 32 in the radial direction. This is because the die-casting type of the end ring 32 requires a pressing margin for pressing the vicinity of the outer peripheral portion of the axial end surface of the rotor core 11a. That is, the end ring 32 cannot be expanded outward in the radial direction of the rotor 11.

It is possible to extend the end ring 32 in the axial direction. However, when the end ring 32 is extended in the axial direction, the height of the rotary compressor 100 increases. In particular, the end ring 32 on the upper bearing 6 side in FIG. 1 has a great influence on the height of the rotary compressor 100.

Therefore, the remaining method of increasing the volume of the end ring 32 is to extend the end ring 32 inward in the radial direction of the rotor 11.

When the end ring 32 is extended inward in the radial direction of the rotor 11, there are various restrictions.
(1) The rotor 11 of the rotary compressor 100 has an air hole 33 (FIGS. 2 and 3) serving as a normal refrigerant passage. If the end ring 32 is extended inward in the radial direction of the rotor 11, the air hole 33 is blocked. Therefore, the end ring 32 needs a relief part (a part for communicating the air hole 33 with the outside) so as not to block the air hole 33.
(2) When the rotor 11 is manufactured by aluminum die casting, it is necessary that the inner periphery of the die-casting mold has a holding allowance for holding the rotor core 11a at least several millimeters. For example, the press margin needs to be 4 mm or more. Therefore, the inner diameter of the end ring 32 needs to be larger by 8 mm or more than the diameter of the shaft hole 31 (FIGS. 2 and 3) of the rotor 11.

Since the inner diameter side of the end ring 32 expands to the drive shaft side so as to block the air hole 33, in order not to block the air hole 33, the end ring 32 has a relief part (a part that communicates the air hole 33 with the outside, for example, In the following, an example in which a portion that communicates the air holes 33 with the space in the sealed container 4 is provided.

In the example shown in FIG. 5, the relief portion is formed by a notch 34 provided on the inner periphery of the end ring 32. The notch 34 is formed in a portion corresponding to the air hole 33 of the end ring 32. The notch 34 is provided so that the air hole 33 is exposed. The rotor 11 shown in FIG. 5 has four air holes 33 formed therein. Accordingly, the notches 34 are also provided at four locations.

Further, when the rotor 11 is manufactured by aluminum die casting, the distance between the inner periphery of the end ring 32 and the shaft hole 31 is secured in order to secure a press margin for the inner peripheral portion of the die cast mold to hold the rotor core 11a. L is 4 mm or more.

The positioning of the air hole 33 of the rotor core 11a and the notch 34 of the end ring 32 can be performed by providing a positioning projection at the tip in the axial direction of the portion corresponding to the notch 34 of the aluminum die cast type. Positioning is performed by inserting positioning protrusions into the air holes 33 of the rotor core 11a.

In the single-phase induction motor, the aluminum bar 30 of the rotor 11 is usually skewed. That is, the aluminum bar 30 is not parallel to the axis of the rotor 11 but is inclined. The skew is performed in order to prevent the voltage of the harmonic component (particularly the slot harmonic) in the magnetic field generated by the winding 20 of the stator 12 from being induced in the aluminum bar 30.

If the aluminum bar 30 of the rotor 11 is skewed, it is difficult to insert the aluminum die-casting positioning projection into the air hole 33 of the rotor core 11a. Therefore, both end portions of the aluminum bar 30 in the axial direction have a predetermined length (longer than the axial length of the positioning protrusion of the aluminum die-casting type) parallel to the shaft. Thereby, the aluminum die-casting positioning protrusion can be smoothly inserted into the air hole 33 of the rotor core 11a. However, even if the aluminum bar 30 of the rotor 11 is skewed over the entire length, it can be inserted by reducing the diameter of the positioning projection of the aluminum die-casting type. In this case, the positioning accuracy between the air hole 33 of the rotor core 11a and the notch 34 of the end ring 32 is slightly deteriorated.

Since the inner diameter side of the end ring 32 expands to the drive shaft side so as to block the air hole 33, in order not to block the air hole 33, the end ring 32 has a relief part (a part that communicates the air hole 33 with the outside, for example, FIG. 6 illustrates another example in which a portion in which the air hole 33 communicates with the space in the sealed container 4 is provided.

As shown in Fig. 6, an end ring air hole 32a communicating with the air hole 33 of the rotor core 11a is formed. The end ring air holes 32a are positioned and formed during aluminum die casting so as to communicate with the air holes 33 of the rotor core 11a. The rotor 11 shown in FIG. 6 has four air holes 33 formed therein. Therefore, the end ring air holes 32a are also provided at four locations.

Further, as in the case of FIG. 5, when the rotor 11 is manufactured by aluminum die casting, the inner periphery of the end ring 32 is secured in order to secure a holding allowance for the inner peripheral portion of the die cast mold to hold the rotor core 11 a. And the distance L between the shaft hole 31 is 4 mm or more.

Further, the positioning of the air hole 33 of the rotor core 11a and the end ring air hole 32a of the end ring 32 can be performed by providing a positioning projection at the tip in the axial direction of the portion corresponding to the end ring air hole 32a of the aluminum die cast type. Positioning is performed by inserting positioning protrusions into the air holes 33 of the rotor core 11a.

Therefore, the diameter of the end ring air hole 32a is slightly larger than the diameter of the air hole 33 of the rotor core 11a.

5 and 6 show an example in which the air holes 33 are provided in the rotor 11. As shown in FIG. 7, an air hole may be provided on the stator 12 side. As shown in FIG. 7, a notch 12c is provided on the outer periphery of the stator core 12a. In FIG. 7, the notches 12c are provided at six locations. A space is formed between the notch 12c of the stator core 12a and the sealed container 4 (body 1). This space becomes the stator air hole 35. These six stator air holes 35 and the air gap 36 between the stator 12 and the rotor 11 (the radial dimension is, for example, about 0.5 mm) are discharged from the compression element 10 at high temperature and high pressure. It becomes the passage of the gas refrigerant. The high-temperature and high-pressure gas refrigerant that has passed through the electric element 13 is discharged from the discharge pipe 16 to the outside (refrigeration cycle).

7, the notch 12c is provided on the outer periphery of the stator core 12a. However, the stator air hole 35 may be provided on the core back of the stator core 12a (the outer portion of the stator slot 12b) instead of the outer periphery.

Thus, by providing the air holes (stator air holes 35) on the stator 12 side, the end ring 32 can be enlarged (the inner diameter side of the end ring 32 is extended so as to be positioned in the vicinity of the drive shaft). Moreover, since the refrigerant | coolant flow rate which passes the stator 12 increases, it has the effect that the coil | winding 20 of the stator 12 is cooled and a temperature rise is suppressed.

In FIG. 7, the stator 12 omits the slots 12b and the like. The slot shape of the rotor 11 is a so-called double basket shape as shown in FIGS. The outer layer slot 40a and the inner layer slot 40b may be connected as shown in FIG. 8, or may not be connected as shown in FIG.

Next, the relationship between the total volume of the end rings 32 on both sides and the volume of the rotor core 11a (this is the end ring volume ratio), the secondary resistance R2 of the rotor 11, and the motor efficiency. Will be described with reference to FIG.

As already described, the secondary resistance R2 of the rotor 11 is expressed by the equation (1). That is, the secondary resistance R2 is proportional to the sum of the resistance Rb of the aluminum bar and the resistance Rr of the end ring. Therefore, even if the end ring volume ratio is increased and the end ring resistance Rr is decreased, the secondary resistance R2 converges on the resistance Rb of the aluminum bar.

As the end ring volume ratio increases, the secondary resistance R2 decreases and the motor efficiency increases. However, as the secondary resistance R2 approaches (converges) the lower limit value, the motor efficiency also converges to the upper limit value.

Therefore, the end ring volume ratio is preferably 13% or more, for example.

Next, the magnetic attraction force acting between the stator 12 and the rotor 11 will be described. A magnetic attractive force P acting between the stator 12 and the rotor 11 is expressed by the following equation.
P = k2 × W × Bm2 (2)
Here, k2 is a constant, W is the core width (axial length) of the stator core 12a, and Bm is the maximum magnetic flux density in the air gap 36 (the distance between the stator 12 and the rotor 11, see FIG. 11). It is.

By using a double squirrel-cage rotor for the rotor 11, the secondary resistance R2 of the rotor 11 can be reduced. Therefore, it is possible to increase the stalling torque (referring to the maximum torque at the rotational speed close to no load from the start). Therefore, if the stationary torque is constant, the design can be made such that the maximum magnetic flux density Bm of the air gap 41 is reduced by that amount (the specification of the winding 20 of the stator 12 is changed).

If the maximum magnetic flux density Bm of the air gap 36 is reduced, the magnetic attractive force P acting between the stator 12 and the rotor 11 is reduced from the equation (2). As shown in FIG. 1, the electric element 13 is only supported on one side by the upper bearing 6 of the compression element 10. That is, the electric element 13 has a cantilevered bearing. Accordingly, the portion of the rotor 11 opposite to the upper bearing 6 side that is not supported by the bearing (the upper portion of the rotor 11 in FIG. 1) swings. The swing of the rotor 11 is related to the magnetic attractive force P. When the magnetic attractive force P is large, the swing of the rotor 11 also increases.

As described above, since the rotary compressor 100 swings around the rotor 11, the air gap length (the length in the radial direction of the air gap 36) is made larger than that in the case where the bearing of the electric element 13 is a double-supported structure. Yes.

By using a double squirrel-cage rotor for the rotor 11, the magnetic attractive force P acting between the stator 12 and the rotor 11 can be reduced. Therefore, the gap length can be made smaller than when a single cage rotor (ordinary cage shape) is used for the rotor 11. For example, the gap length between the stator 12 and the rotor 11 (the radial length of the gap) can be set as follows.
(1) When the outer diameter of the stator 12 is 140 mm or less, the gap length is 0.6 mm or less;
(2) When the outer diameter of the stator 12 exceeds 140 mm, the gap length is 0.8 mm or less.

Further, as shown in FIG. 12, a harmonic component (torque ripple) is superimposed on the torque generated by the electric element 13 (induction motor). In FIG. 12, the horizontal axis represents the load torque [Nm], and the vertical axis represents the torque ripple [%] (ratio to the fundamental wave torque). When the double cage type and the single cage type (ordinary cage type) are compared, the torque ripple of the double cage type is smaller than the torque ripple of the single cage type in almost the entire load torque.

By making the rotor 11 into a double squirrel cage shape, the magnetic attraction force P (P = k2 × W × Bm2) is reduced at the same stationary torque, and the swinging of the rotor 11 can be suppressed. It has already been described that the gap length can be 0.6 mm or 0.8 mm or less depending on the outer diameter. Further, as shown in FIG. 13, a part of the outer periphery of the rotor core 11 a (on the side opposite to the upper bearing 6 side in FIG. 1) is cut by a predetermined amount to form a cutting portion 38. And if the gap length in the cutting part 38 is 0.6 mm or 0.8 mm or less depending on the outer diameter of the stator 12, the gap length of the part other than the cutting part 38 (part close to the upper bearing 6 in FIG. 1). Can be further reduced, and the motor efficiency can be improved.

In the double squirrel-cage rotor, the slot 40 of the rotor core 11a is composed of an outer layer slot 40a and an inner layer slot 40b. Therefore, in the slot 40 portion, the contact area between the core (rotor core 11a) and the secondary conductor (outer layer aluminum bar 30a and inner layer aluminum bar 30b) is wide, and the insulation between the core and the secondary conductor deteriorates. Alternatively, the core and the secondary conductor are insulated by post heat. Brewing refers to heat treatment of the rotor core 11a to form an oxide film on the surface of the rotor core 11a. Post-heating means that after the conductor is die-cast, the rotor 11 is heated, immersed in a liquid such as water and rapidly cooled to create a gap between the secondary conductor in the slot 40 and the rotor core 11a. The secondary conductor is insulated.

When the insulation between the rotor core 11a and the secondary conductor deteriorates, a sag occurs in the torque waveform (torque characteristics with respect to the rotational speed) of the electric element 13. If a sag occurs in the torque waveform of the electric element 13, this leads to a starting failure of the rotary compressor 100.

R22 refrigerant may be used as the refrigerant in the refrigeration cycle in which the rotary compressor 100 is incorporated. In that case, when the R22 refrigerant is used, the winding 20 temperature of the stator 12 is likely to rise. Therefore, it is difficult to reduce the size of the motor. Since the efficiency is improved by using the double squirrel-cage rotor for the electric element 13, it is possible to reduce the size or increase the capacity with the same size.

Also, R410a refrigerant is used as the refrigerant of the refrigeration cycle in which the rotary compressor 100 is incorporated. When the R410a refrigerant is used, the refrigerating capacity is increased by about 10% compared to the R22 refrigerant. Therefore, when the R410a refrigerant is used, the torque of the electric element 13 needs to be increased by that amount (about 10%) compared to the R22 refrigerant. In this case, torque improvement by using a double cage rotor for the rotor 11 is effective.

For the rotary compressor 100 using the R22 refrigerant, the electric element 13 corresponding to the R410a refrigerant is configured by simply selecting a motor based on the refrigerating capacity ratio and replacing the conventional single cage rotor with a double cage rotor. be able to.

Further, CO ₂ (R744) refrigerant is used as the refrigerant of the refrigeration cycle in which the rotary compressor 100 is incorporated. The CO ₂ refrigerant has a very high compression ratio, and at present, the electric element 13 of the rotary compressor 100 using the CO ₂ refrigerant is mainly a brushless DC motor. By using the rotary compressor 100 to the double squirrel cage motor that uses CO ₂ refrigerant, the compressor size without increasing the size of a rotary compressor using CO ₂ refrigerant equipped with constant speed induction motor 100 Can be realized.

FIG. 14 is a configuration diagram of a refrigeration cycle apparatus using the rotary compressor 100. The refrigeration cycle apparatus is, for example, an air conditioner. The rotary compressor 100 is connected to a single-phase power source 18. An operating capacitor 60 is connected between the auxiliary winding 20 b of the single-phase induction motor of the rotary compressor 100 and the single-phase power source 18. Electric power is supplied from the single-phase power source 18 to the rotary compressor 100, and the rotary compressor 100 is driven. The refrigeration cycle apparatus (air conditioner) includes a rotary compressor 100, a four-way valve 51 that switches a refrigerant flow direction, an outdoor heat exchanger 52, a decompression device 53, an indoor heat exchanger 54, and the like. These are connected by refrigerant piping.

In the refrigeration cycle apparatus (air conditioner), for example, during the cooling operation, the refrigerant flows as indicated by arrows in FIG. The outdoor heat exchanger 52 becomes a condenser. Moreover, the indoor heat exchanger 54 becomes an evaporator.

Although not shown, during the heating operation of the refrigeration cycle apparatus (air conditioner), the refrigerant flows in the direction opposite to the arrow in FIG. The direction in which the refrigerant flows is switched by the four-way valve 51. At this time, the outdoor heat exchanger 52 becomes an evaporator. Moreover, the indoor heat exchanger 54 becomes a condenser.

In addition, HFC refrigerants represented by R134a, R410a, R407c, etc., and natural refrigerants represented by R744 (CO ₂ ), R717 (ammonia), R600a (isobutane), R290 (propane), etc. are used as the refrigerant. The As the refrigerating machine oil, weakly compatible oils typified by alkylbenzene oils or compatible oils typified by ester oils are used. In addition to the rotary type (rotary type), a reciprocating type, a scroll type, etc. can be used for the compressor.

By using the rotary compressor 100 equipped with a double squirrel-cage rotor in the refrigeration cycle, it is possible to improve the performance of the refrigeration cycle apparatus, reduce the size, and reduce the price.

In the above description, an example is shown in which aluminum is used as the material of the squirrel-cage winding, but copper may be used instead of aluminum.

In addition, the single-phase induction motor using the double squirrel-cage rotor has been described, but the same effect can be obtained when applied to a three-phase induction motor.

The electric motor for a compressor according to the embodiment of the present invention can expand the end ring without blocking the air hole of the rotor core by configuring the relief portion with a notch provided in the inner periphery of the end ring.

The electric motor for a compressor according to the embodiment of the present invention can further expand the end ring without blocking the air hole of the rotor core by configuring the escape portion with the end ring air hole provided in the end ring.

An electric motor for a compressor according to an embodiment of the present invention is housed together with a compression element that compresses a refrigerant in an airtight container, and is connected to the compression element by a drive shaft to drive the compression element. A stator that is fixed to the inner periphery of the container, a rotor that is provided inside the stator and has a rotor core, and an outer layer secondary conductor and an inner layer secondary conductor that are cast into the rotor core; A double squirrel-cage conductor composed of a secondary conductor and an end ring is provided, and the stator is provided with a stator air hole serving as a refrigerant passage so that the inner diameter side of the end ring is positioned near the drive shaft. By configuring, the end ring can be further expanded. As shown in the equation (1), the secondary resistance R2 of the rotor 11 is the sum of the resistance Rb of the aluminum bar and the resistance Rr of the end ring. By enlarging the end ring, the resistance Rr of the end ring decreases, and as a result, the secondary resistance R2 of the rotor 11 decreases. When the secondary resistance R2 of the rotor 11 is reduced, the efficiency during operation of the compressor motor is improved.

In the electric motor for a compressor according to the embodiment of the present invention, the stator includes a stator core, a notch is provided in the outer peripheral portion of the stator core, and the space between the hermetic container and the outer peripheral portion of the stator core is notched. By providing the stator air holes in the stator, the winding of the stator is cooled by the refrigerant passing through the stator air holes, and the temperature rise is suppressed.

An electric motor for a compressor according to an embodiment of the present invention includes a shaft hole in which a rotor iron core is fitted with a drive shaft, and the inner diameter of the end ring is larger than the diameter of the shaft hole by 8 mm or more, thereby It is possible to secure the press-down allowance of the die when die casting the shape conductor.

The motor for a compressor according to the embodiment of the present invention can improve the motor efficiency by setting the total volume of the end ring to 13% or more of the volume of the rotor core.

In the compressor motor according to the embodiment of the present invention, the compression element includes a bearing, and the compressor motor is supported on one side by the bearing of the compression element, the bearing has a cantilever structure, and rotates with the stator. The motor efficiency can be improved by setting the radial length of the gap between the child and the child as follows.
(1) When the outer diameter of the stator is smaller than 140 mm, the radial length of the gap is 0.6 mm or less;
(2) When the outer diameter of the stator exceeds 140 mm, the radial length of the gap is 0.8 mm or less.

In the compressor motor according to the embodiment of the present invention, the outer periphery on the opposite side of the bearing of the compression element of the rotor core is cut, and the outer diameter is made smaller than the outer periphery on the bearing side of the compression element of the rotor core. As a result, the radial length of the gap between the stator and the rotor can be further reduced, and the motor efficiency can be improved.

The compressor according to the embodiment of the present invention can realize energy saving, downsizing, and low price by mounting the compressor motor.

In the compressor according to the embodiment of the present invention, even when R22 is used as the refrigerant, the capacity can be reduced or the capacity can be increased with the same size.

In the compressor according to the embodiment of the present invention, when R410a is used as the refrigerant, torque improvement by using a double cage rotor as the rotor is effective.

The compressor according to the embodiment of the present invention can realize a compressor using a CO ₂ refrigerant equipped with a constant speed motor without increasing the size of the compressor even when CO ₂ is used as the refrigerant.

In the refrigeration cycle apparatus according to the embodiment of the present invention, the compressor, the condenser, the decompression apparatus, and the evaporator are connected by a refrigerant pipe, so that the performance of the refrigeration cycle apparatus is improved, downsized, and reduced. Pricing is possible.

FIG. 3 shows the first embodiment, and is a longitudinal sectional view of the rotary compressor 100. FIG. 3 is a diagram illustrating the first embodiment and is a cross-sectional view illustrating the electric element 13. FIG. 3 is a cross-sectional view showing the rotor 11 of the electric element 13 according to the first embodiment. FIG. 3 is a diagram showing the first embodiment, and is a perspective view showing a rotor 11 of the electric element 13. FIG. 4 is a diagram illustrating the first embodiment, and is a side view of the rotor 11 in which a cutout 34 is provided in an end ring 32; FIG. 5 shows the first embodiment and is a side view of the rotor 11 provided with an end ring air hole 32a. FIG. 5 shows the first embodiment and is a cross-sectional view of the vicinity of the electric element 13 showing an example in which an air hole is provided on the stator 12 side. FIG. 5 shows the first embodiment, and is a cross-sectional view of the slot of the rotor 11. FIG. 5 shows the first embodiment, and is a cross-sectional view of the slot of the rotor 11. FIG. 5 is a diagram illustrating the first embodiment and is a diagram illustrating a relationship between a volume ratio between an end ring 32 and a rotor core 11a, a secondary resistance R2, and motor efficiency. FIG. 3 shows the first embodiment and is a partial cross-sectional view of the electric element 13. The figure which shows Embodiment 1 and is a figure which shows the torque ripple waveform of a single cage type and a double cage type. FIG. 5 shows the first embodiment, and is a side view of a rotor 11 in which a cutting portion is provided on a part of the outer periphery. FIG. 3 shows the first embodiment, and is a configuration diagram of a refrigeration cycle apparatus using a rotary compressor 100. FIG.

Explanation of symbols

1 body part, 2 upper dish container, 3 lower dish container, 4 sealed container, 5 cylinder, 6 upper bearing, 7 lower bearing, 8 drive shaft, 9 rolling piston, 10 compression element, 11 rotor, 11a rotor core, 12 stator, 12a stator core, 12b stator slot, 12c notch, 13 motor elements, 14 suction muffler, 15 suction pipe, 16 discharge pipe, 17 glass terminal, 18 single phase power supply, 20 winding, 20a main winding Wire, 20b auxiliary winding, 21 lead wire, 30 aluminum bar, 30a outer layer aluminum bar, 30b inner layer aluminum bar, 31 shaft hole, 32 end ring, 32a end ring air hole, 33 air hole, 34 notch, 35 stator air hole, 36 gap, 38 cutting part, 40a outer layer slot, 40b inner layer slot, 51 four-way valve 52 outdoor heat exchanger, 53 the decompressor, 54 indoor heat exchanger, 60 run capacitor, 100 a rotary compressor.

Claims

In a motor for a compressor that is housed together with a compression element that compresses a refrigerant in an airtight container and is connected to the compression element by a drive shaft to drive the compression element.
A stator fixed to the inner periphery of the sealed container;
A rotor provided inside the stator and having a rotor core;
A double squirrel-cage conductor composed of an outer ring secondary conductor and an inner layer secondary conductor and an end ring, which are cast into the rotor core;
The rotor core is provided with an air hole serving as a passage for the refrigerant,
The end ring expands to the drive shaft side so that the inner diameter side closes the air hole, and has an escape portion that allows the air hole to communicate with the space of the sealed container so as not to close the air hole. An electric motor for a compressor.
2. The electric motor for a compressor according to claim 1, wherein the relief portion is formed by a notch provided in an inner periphery of the end ring.
The motor for a compressor according to claim 1, wherein the escape portion is configured by an end ring air hole provided in the end ring.
In a motor for a compressor that is housed together with a compression element that compresses a refrigerant in an airtight container and is connected to the compression element by a drive shaft to drive the compression element.
A stator fixed to the inner periphery of the sealed container;
A rotor provided inside the stator and having a rotor core;
A double squirrel-cage conductor composed of a secondary conductor having an outer layer secondary conductor and an inner layer secondary conductor and an end ring, which is cast into the rotor core;
The stator is provided with a stator air hole serving as a passage for the refrigerant,
An electric motor for a compressor, wherein the inner diameter side of the end ring is positioned in the vicinity of the drive shaft.
The stator includes a stator core, a notch is provided in an outer periphery of the stator core, and the stator air hole is provided between the hermetic container and a notch in the outer periphery of the stator core. The electric motor for a compressor according to claim 4, wherein the electric motor is used.
2. The electric motor for a compressor according to claim 1, wherein the rotor iron core has a shaft hole for fitting with the drive shaft, and an inner diameter of the end ring is made 8 mm or more larger than a diameter of the shaft hole.
The motor for a compressor according to claim 4, wherein the rotor core has a shaft hole that fits with the drive shaft, and an inner diameter of the end ring is made 8 mm or more larger than a diameter of the shaft hole.
The motor for a compressor according to claim 1, wherein the total volume of the end ring is 13% or more of the volume of the rotor core.
The motor for a compressor according to claim 4, wherein the total volume of the end ring is 13% or more of the volume of the rotor core.
The compression element includes a bearing, and the electric motor for the compressor is supported on one side by the bearing of the compression element, the bearing has a cantilever structure,
The electric motor for a compressor according to claim 1, wherein the radial length of the gap between the stator and the rotor is set as follows.
(1) When the outer diameter of the stator is smaller than 140 mm, the radial length of the gap is 0.6 mm or less;
(2) When the outer diameter of the stator exceeds 140 mm, the radial length of the gap is 0.8 mm or less.
11. The compression according to claim 10, wherein an outer periphery of the rotor core opposite to the bearing of the compression element is cut to have an outer diameter smaller than an outer periphery of the rotor core on the bearing side of the compression element. Electric motor for machine.
A compressor equipped with the compressor motor according to claim 1.
The compressor according to claim 12, wherein R22 is used as the refrigerant.
The compressor according to claim 12, wherein R410a is used as the refrigerant.
The compressor according to claim 12, wherein CO 2 is used as the refrigerant.
13. A refrigeration cycle apparatus comprising: a compressor according to claim 12; a condenser; a decompressor; and an evaporator connected by refrigerant piping.
A refrigeration cycle apparatus comprising: a compressor according to claim 13; a condenser; a decompressor; and an evaporator connected by refrigerant piping.
15. A refrigeration cycle apparatus comprising the compressor according to claim 14, a condenser, a decompression device, and an evaporator connected by refrigerant piping.
A refrigeration cycle apparatus comprising: a compressor according to claim 15; a condenser; a decompressor; and an evaporator connected by refrigerant piping.