JP2012172622A - Hermetic compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic compressor, which is capable of improving demagnetization characteristics to a demagnetizing field current by lowering a temperature of a permanent magnet provided in a rotor, and capable of suppressing demagnetization to a demagnetizing field even when the dysprosium content of the permanent magnet is reduced.SOLUTION: The hermetic compressor includes: a hermetic container storing refrigerating machine oil at a bottom; a compression element which is provided inside the hermetic container and compresses a refrigerant, and in which a slide part is lubricated with refrigerating machine oil; an electric element which is provided above the compression element inside the hermetic container, drives the compression element, and provided with a stator and a rotor disposed on the inner side of the stator and using a permanent magnet; and a shield plate which is provided above the compression element and below the electric element, and guides the refrigerant discharged from the compression element to the stator of the electric element.

Description

  The present invention relates to a hermetic compressor. Specifically, the present invention relates to a refrigerant gas flow path inside the hermetic compressor.

  Conventionally, in a hermetic compressor, an electric element and a compression element are provided in a hermetic container, and a donut-shaped shielding plate having a hollow center portion is provided above the electric element and discharged to the outside of the hermetic container. A hermetic compressor that reduces the amount of refrigeration oil discharged is proposed (see, for example, Patent Document 1).

JP 2008-31913 A

  However, the hermetic compressor of Patent Document 1 can reduce the amount of refrigerating machine oil discharged to the outside of the hermetic container, but the discharge gas containing the refrigerating machine oil passes through the rotor of the electric element, so that The child is heated by the discharge gas. When using a permanent magnet for a rotor, since the temperature of the permanent magnet was high, there existed a subject that the demagnetization tolerance with respect to the demagnetizing-field current of a permanent magnet was not enough.

  The present invention has been made to solve the above-described problems. By reducing the temperature of the permanent magnet provided in the rotor, the demagnetization characteristic against the demagnetizing field current can be improved, and the permanent magnet can be made permanent. Provided is a hermetic compressor that can suppress demagnetization against a demagnetizing field even if the dysprosium content of a magnet is reduced.

A hermetic compressor according to the present invention includes a hermetic container in which refrigeration oil is stored at the bottom,
A compression element that is provided in a sealed container, compresses the refrigerant, and the sliding portion is lubricated by the refrigerating machine oil;
An electric element provided above the compression element in the hermetic container, driving the compression element, having a stator and a rotor disposed inside the stator and using a permanent magnet;
A shielding plate is provided above the compression element and below the electric element, and guides the refrigerant discharged from the compression element to the stator of the electric element.

  In the hermetic compressor according to the present invention, the shielding plate for guiding the refrigerant discharged from the compression element to the stator of the electric element is provided above the compression element and below the electric element. Can be lowered. Therefore, demagnetization with respect to the demagnetizing field can be suppressed even if the dysprosium content of the permanent magnet is reduced.

FIG. 3 shows the first embodiment, and is a cross-sectional view of the permanent magnet motor 100 of the rotary compressor 300. FIG. 5 shows the first embodiment, and is a cross-sectional view of the stator 12. FIG. 5 shows the first embodiment, and is a cross-sectional view of the stator core 12a. FIG. 3 shows the first embodiment and is a cross-sectional view of the rotor 11. FIG. 5 shows the first embodiment and is a cross-sectional view of the rotor core 11a. The elements on larger scale of FIG. FIG. 3 is a diagram showing the first embodiment, showing demagnetization characteristics, and a magnetic flux amount characteristic diagram with respect to a demagnetizing field current. FIG. 3 is a diagram showing the first embodiment, showing demagnetization characteristics, and a magnetic flux amount characteristic diagram with respect to a demagnetizing field current. The figure which shows Embodiment 1 is a figure which shows a demagnetization characteristic, and is a magnet temperature characteristic figure with respect to a dysprosium (Dy) content rate. FIG. 3 shows the first embodiment, and is a longitudinal sectional view of the rotary compressor 300, and is a sectional view taken along the line A-O-B in FIG. FIG. 5 shows the first embodiment and is a cross-sectional view of the shielding plate 80. FIG. 5 shows the first embodiment, and is a configuration diagram of permanent magnets per pole, and is a perspective view of permanent magnets 13b and 13c divided into permanent magnets 13b and 13c. FIG. 5 shows the first embodiment, and is a configuration diagram of permanent magnets per pole, and is a perspective view of permanent magnets 13d and 13e divided into permanent magnets 13d and 13e. FIG. 5 shows the first embodiment, and is a configuration diagram of permanent magnets per pole, and is a perspective view of permanent magnets 13f, 13g, 13h, and 13j divided into permanent magnets 13f, 13g, 13h, and 13j. FIG. 5 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 301 of a first modification. FIG. 5 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 302 of a second modification. FIG. 5 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 303 of a third modification. FIG. 5 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 304 of a fourth modification. FIG. 3 is a diagram illustrating the first embodiment, and is a circuit diagram of a drive circuit 1 of the permanent magnet motor 100.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of the permanent magnet electric motor 100 of the rotary compressor 300 showing the first embodiment. A permanent magnet motor 100 shown in FIG. 1 is a 6-pole concentrated winding brushless DC motor. The permanent magnet motor 100 includes a stator 12 and a rotor 11. Hereinafter, the permanent magnet motor 100 may be simply referred to as a motor or an electric motor.

  As shown in the partially enlarged view of FIG. 1, a gap 60 (also referred to as an air gap) having a predetermined radial dimension is provided between the stator 12 and the rotor 11. For example, the gap 60 between the stator 12 and the rotor 11 has a radial dimension of about 0.2 to 2.0 mm.

  The rotor 11 is provided on the inner peripheral side of the stator 12 through a gap 60. Details of the configuration of the rotor 11 will be described later.

  The stator 12 is fitted to the inner periphery of a trunk portion 72a of a sealed container 72 (see FIG. 10) of a rotary compressor 300 described later. The stator 12 and the body 72a of the sealed container 72 are fitted by, for example, shrink fitting.

  When performing shrink fitting between the stator 12 and the trunk portion 72a of the sealed container 72, the trunk portion 72a is heated to about 200 ° C. by electromagnetic induction heating and is shrink-fitted to the stator 12 in an expanded state. The fitting allowance (shrinkage allowance) between the trunk portion 72a and the stator 12 is appropriately selected in the range of several tens to several hundreds of μm according to the weight of the stator 12.

  By shrink fitting, the inner diameter of the barrel portion 72a is set smaller than the outer diameter of the stator 12 at room temperature, and when the stator 12 is fitted to the barrel portion 72a, the barrel portion 72a is heated and expanded. When the inner diameter of the barrel 72a is inserted larger than the outer diameter of the stator 12, and the stator 12 returns to room temperature, both are fixed. The fitting allowance (shrink fitting allowance) refers to the difference between the outer diameter of the stator 12 and the inner diameter of the trunk portion 72a at room temperature (the outer diameter of the stator 12> the inner diameter of the trunk portion 72a).

  FIG. 2 is a cross-sectional view of the stator 12 showing the first embodiment. The stator 12 includes a substantially cylindrical (doughnut-shaped) stator core 12a, and stator slots 12b (9 slots, see FIG. 3) of the stator core 12a. Phase windings 20 are provided. As the winding 20, a magnet wire or the like in which an insulating film is applied to the outer periphery of a copper wire is generally used.

  Insulator 12g is inserted into stator slot 12b to ensure electrical insulation between winding 20 and stator core 12a.

  As shown in FIG. 2, the winding 20 is directly wound around one stator tooth portion 12e (9 stator teeth portions, see FIG. 3) via an insulating material 12g. Such a winding method is generally called concentrated winding.

  The U-phase winding, V-phase winding and W-phase winding are connected by Y connection (star connection, star connection), and the permanent magnet motor 100 generates torque by applying a three-phase voltage to each winding. To do. Although the Y connection is described here, a Δ connection (triangular connection) may be used.

  FIG. 3 shows the first embodiment, and is a cross-sectional view of the stator core 12a. The stator core 12a is manufactured by punching a magnetic steel sheet having a thickness of about 0.1 to 1.5 mm into a predetermined shape, then stacking a predetermined number of sheets in the axial direction, and fixing by punching or welding.

  As shown in FIG. 3, a stator slot 12b is formed in the stator core 12a along the inner peripheral edge. The nine stator slots 12b are arranged at substantially equal intervals in the circumferential direction. In the example of FIG. 3, all the stator slots 12b have the same shape. However, the stator slots 12b may be configured in a large and small slot shape in which a part of the size is changed.

  Between adjacent stator slots 12b, a stator tooth portion 12e, which is a part of the stator core 12a, is formed. For this reason, the number of stator slots 12b and the number of stator teeth 12e are the same. In the example of FIG. 3, the stator 12 includes nine stator slots 12b and nine stator teeth 12e.

  The stator slot 12b extends in the radial direction. The stator slot 12b opens to the inner peripheral edge. This opening is referred to as a slot opening 12d.

  As shown in FIG. 3, nine stator notches 12c are provided on the outer peripheral surface of the stator core 12a (the outer peripheral side of the stator tooth portion 12e). However, this is an example, and the number of stator cutouts 12c may be arbitrary.

  Further, in the stator core 12a, the outer core portion of the stator slot 12b is generally called a core back 12f. The magnetic path cross-sectional area of the core back 12f in the portion where the stator notch 12c is formed is smaller than the magnetic path cross-sectional area of the portion whose outer periphery is an arc shape. Therefore, normally, the stator notch 12c is provided on the outer peripheral side (on the radial extension line) of the stator tooth portion 12e. When the stator notch 12c is provided in the core back 12f outside the stator slot 12b, the magnetic path cross-sectional area of the core back 12f in the stator notch 12c portion is reduced by the amount of the stator notch 12c.

  When the permanent magnet motor 100 is mounted on a rotary compressor 300 (which will be described later) which is an example of a hermetic compressor used in the refrigeration cycle, the stator 12 is a body portion of a cylindrical sealed container 72 of the rotary compressor 300. The inner periphery of 72a is shrink-fitted. Inside the rotary compressor 300, refrigerant gas (including refrigeration oil) passes through the permanent magnet motor 100. Therefore, the permanent magnet motor 100 requires a refrigerant gas passage.

  FIG. 4 is a cross-sectional view of the rotor 11 showing the first embodiment. A rotor 11 provided on the inner peripheral side of the stator 12 via a gap 60 includes a rotor core 11a, permanent magnets 13a (the six permanent magnets 13a constitute a six-pole rotor 11), and a rotating shaft 90. Is provided. The permanent magnet 13a is embedded in the rotor core 11a as will be described later.

  The permanent magnet 13a is a rare earth permanent magnet mainly composed of neodymium (element symbol: Nd), iron (element symbol: Fe), and boron (element symbol: B). In order to increase the coercive force, the dysprosium ( Element symbol: Dy) is contained. In other words, the permanent magnet 13a is a rare earth permanent magnet containing neodymium, iron, boron, and dysprosium.

  After the permanent magnet 13a is inserted into the magnet insertion hole 11f (see FIG. 5) of the rotor core 11a, end plates (not shown) are arranged at both ends in the stacking direction of the rotor core 11a, and rivets (see FIG. The rotor 11 is manufactured by inserting (not shown).

  5 is a diagram showing the first embodiment, and is a cross-sectional view of the rotor core 11a. FIG. 6 is a partially enlarged view of FIG. As shown in FIG. 5, the rotor core 11a is formed by punching electromagnetic steel sheets having a plate 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, and removing and caulking and bonding. It is fixed and manufactured by etc. In general, the electrical steel sheet of the inner (inner peripheral side) portion of the stator core 12a is often used.

  Generally, the rotor core 11a is often punched from the same material as the stator core 12a, but the material of the rotor core 11a may be different from the material of the stator core 12a. For example, the highly efficient permanent magnet motor 100 with reduced iron loss can be obtained by setting the thickness of the rotor core 11a to 0.5 mm and the thickness of the stator core 12a to 0.35 mm.

  The rotor iron core 11a is provided with six magnet insertion holes 11f, and six plate-like permanent magnets 13a are inserted into the magnet insertion holes 11f to constitute a six-pole rotor 11. Further, a shaft hole 11g into which the rotating shaft 90 is fitted is formed at a substantially central portion of the rotor core 11a.

  As shown in FIG. 6, the magnet insertion hole 11f is formed long in the circumferential direction so as to be along the outer peripheral edge in the vicinity of the outer peripheral edge of the rotor core 11a. A central portion of the magnet insertion hole 11f is a magnet insertion portion 11f-1 into which the permanent magnet 13a is inserted. Both ends of the magnet insertion portion 11f-1 are leakage magnetic flux suppression holes 11f-2 that partially remain as spaces even when the permanent magnet 13a is inserted. Leakage magnetic flux suppression hole 11f-2 suppresses magnetic flux leakage at the circumferential end of permanent magnet 13a.

  As shown in FIGS. 5 and 6, the rotor core 11 a is provided with a plurality of slits 40 in the core portion existing on the outer peripheral side of the magnet insertion hole 11 f. For example, a total of seven slits 40 are provided symmetrically on both sides of the magnetic pole center line. However, one of them is on the magnetic pole center line.

  The slit 40 smoothes the magnetic flux distribution in the iron core portion on the outer peripheral side of the magnet insertion hole 11f. For example, the slit 40 can be concentrated on one point on the extension line of the magnetic pole center line of the permanent magnet 13a. It is formed so as to extend from the circumferential side toward the outer circumferential side.

  However, the extending direction of the slit 40 may not extend toward the magnetic pole center. For example, it may be parallel to the magnetization direction of the permanent magnet 13a (perpendicular to the magnet insertion hole 11f). Furthermore, the shape of the slit 40 is substantially rectangular in cross section in the examples of FIGS. 5 and 6, but is not limited to this shape. Any shape such as an ellipse or a trapezoid may be used as long as the rotor core 11a is formed to extend from the inner peripheral side toward the outer peripheral side. Further, although the slits 40 are provided symmetrically on both sides of the magnetic pole center line, they may be provided asymmetrically.

  By arranging the plurality of slits 40, the magnetic flux distribution on the outer periphery of the rotor core 11a can be smoothed, and the harmonic component of the voltage induced in the winding 20 of the stator 12 can be reduced. .

  When driving by applying a three-phase sine wave AC voltage to the winding 20, only the fundamental wave component of the voltage induced in the winding 20 of the stator 12 contributes effectively as the torque of the permanent magnet motor 100. Yes, the harmonic component is torque pulsation (torque ripple).

  Although this torque ripple causes the vibration and noise of the motor to increase, the permanent magnet motor 100 with less vibration and noise can be obtained by arranging the plurality of slits 40. Further, by mounting the permanent magnet electric motor 100 on the rotary compressor 300, the rotary compressor 300 with low vibration and low noise can be obtained.

  When a large demagnetizing field current flows through the winding 20 of the stator 12, the permanent magnet 13a causes irreversible demagnetization (hereinafter referred to as demagnetization), and the magnetic force (magnetic flux amount) of the permanent magnet 13a is reduced. There is a problem of lowering. Further, the demagnetization due to the demagnetizing current tends to be gradually demagnetized from the surface of the permanent magnet 13a on the side close to the stator 12, particularly from the vicinity of the corner at the circumferential end.

  Since the magnetic flux of the demagnetizing field of the stator 12 passes through the iron core having a low magnetic resistance, the permanent magnet 13a can be used not only when the slit 40 is not present but also when the width dimension (circumferential direction) of the slit 40 is small. There is a possibility of demagnetizing the circumferential end of the.

  7 to 9 are diagrams showing the first embodiment, FIG. 7 is a diagram showing a demagnetization characteristic, a magnetic flux amount characteristic diagram with respect to a demagnetizing current, and FIG. 8 is a diagram showing a demagnetizing property with respect to a demagnetizing current. FIG. 9 is a diagram showing the demagnetization characteristic, and is a magnet temperature characteristic diagram with respect to the dysprosium (Dy) content rate.

  The demagnetization characteristics of the permanent magnet 13a will be described with reference to FIGS. Here, as described above, the permanent magnet 13a is a rare earth permanent magnet mainly composed of neodymium, iron, and boron, and dysprosium (Dy) is added to increase the coercive force.

  As shown in FIG. 7, for example, when a demagnetizing current is applied to the permanent magnet 13a at the magnet temperature T1, if the demagnetizing current is low, the amount of magnetic flux of the permanent magnet 13a does not decrease, but When a demagnetizing field current flows, the amount of magnetic flux decreases, and when a further demagnetizing field current is applied, the amount of magnetic flux tends to decrease rapidly.

  The same tendency as in T1 is observed at T2 and T3, but the demagnetizing current at which magnetic flux reduction starts changes. Here, the respective temperatures have a relationship of T1 <T2 <T3, and when the magnet temperature increases, the demagnetizing field current at which the reduction of the magnetic flux amount starts decreases. That is, as shown in FIG. 7, it can be seen that the demagnetizing current with a predetermined magnetic flux amount increases as the magnet temperature decreases.

  That is, in the same demagnetizing field current, it is difficult to demagnetize when the magnet temperature is low, and it is easy to demagnetize when the magnet temperature is high.

  FIG. 8 shows the demagnetization characteristics when the Dy content is changed under a constant magnet temperature condition. The permanent magnet having a Dy content of 7% has a reduced magnetic flux compared with the case of a Dy content of 3%. The demagnetizing field current that starts is increased. That is, when the Dy content is high, it is difficult to demagnetize, and when the Dy content is low, it is easy to demagnetize.

  From the characteristic diagrams of FIGS. 7 and 8, FIG. 9 shows the magnet temperature characteristics with respect to the Dy content ratio that provides the predetermined magnetic flux amount (predetermined demagnetization factor) characteristics with the same demagnetizing field current. By increasing the Dy content, the temperature of the permanent magnet 13a can be increased. That is, when the Dy content is decreased, it is indicated that the temperature of the permanent magnet 13a needs to be decreased.

  As shown in FIG. 9, when a permanent magnet having a Dy content higher than 4% is used, even if the Dy content is increased, the temperature of the permanent magnet cannot be made too high. That is, it shows that the magnet temperature characteristic with respect to the Dy content does not change greatly.

  On the other hand, when a permanent magnet having a Dy content of 4% or less is used, it can be seen that the magnet temperature characteristics at which the predetermined magnetic flux amount changes sharply with respect to the change in the Dy content. That is, in order to use a permanent magnet having a Dy content, it is necessary to lower the magnet temperature.

  FIG. 10 shows the first embodiment, which is a longitudinal sectional view of the rotary compressor 300 and a sectional view taken along the line A-O-B in FIG.

  The configuration of the rotary compressor 300 will be described with reference to FIG. As shown in FIG. 10, the rotary compressor 300 houses a compression element 200, a permanent magnet motor 100 that is an electric element, and a refrigerating machine oil (not shown) in a sealed container 72. The refrigerating machine oil is stored at the bottom in the sealed container 72. The refrigerating machine oil mainly lubricates the sliding portion of the compression element 200. The sealed container 72 includes an upper dish container 72b and a body portion 72a.

  The compression element 200 includes a cylinder 79, an upper bearing 74 (an example of a bearing), a lower bearing 75 (an example of a bearing), a rotating shaft 90, a rolling piston 77, a discharge muffler 76, a vane (not shown), and the like.

  A cylinder 79 in which a compression chamber is formed includes a cylinder chamber having an outer periphery that is substantially circular in plan view and a space that is substantially circular in plan view. The cylinder chamber is open at both axial ends. The cylinder 79 has a predetermined axial height in a side view.

  Parallel vane grooves (not shown) that communicate with a cylinder chamber that is a substantially circular space of the cylinder 79 and extend in the radial direction are provided so as to penetrate in the axial direction.

  In addition, a back pressure chamber (not shown) that is a substantially circular space in plan view communicating with the vane groove is provided on the back surface (outside) of the vane groove.

  A suction port through which suction gas from the suction pipe 71 passes penetrates the cylinder chamber from the outer peripheral surface of the cylinder 79.

  The cylinder 79 is provided with a discharge port (not shown) in which the vicinity of the edge of a circle forming a cylinder chamber which is a substantially circular space is cut out.

  The rolling piston 77 rotates eccentrically in the cylinder chamber. The rolling piston 77 is ring-shaped, and the inner periphery of the rolling piston 77 is slidably fitted to the eccentric shaft portion 90 a of the rotating shaft 90.

  The vane is housed in the vane groove of the cylinder 79, and the vane is always pressed against the rolling piston 77 by a vane spring (not shown) provided in the back pressure chamber. In the rotary compressor 300, since the inside of the sealed container 72 is at a high pressure, when the operation is started, a force due to the differential pressure between the high pressure in the sealed container 72 and the pressure in the cylinder chamber acts on the back surface (back pressure chamber side) of the vane. Therefore, the vane spring is mainly used for the purpose of pressing the vane against the rolling piston 77 when the rotary compressor 300 is started (in a state where there is no difference between the pressure in the sealed container and the cylinder chamber).

  The shape of the vane is a flat shape (the thickness in the circumferential direction is smaller than the length in the radial direction and the axial direction).

  The upper bearing 74 is slidably fitted to the main shaft portion 90b (a portion above the eccentric shaft portion 90a) of the rotating shaft 90, and one end face (permanent magnet) of the cylinder chamber (including the vane groove) of the cylinder 79. The motor 100 side) is closed.

  A discharge valve (not shown) is attached to the upper bearing 74. The upper bearing 74 has a substantially inverted T shape when viewed from the side.

  The lower bearing 75 is slidably fitted to the auxiliary shaft portion 90c (a portion below the eccentric shaft portion 90a) of the rotary shaft 90, and the other end surface (freezing) of the cylinder chamber (including the vane groove) of the cylinder 79. Block the machine oil side). The lower bearing 75 is substantially T-shaped when viewed from the side.

  A discharge muffler 76 is attached to the outer bearing 74 on the outer side (permanent magnet motor 100 side). The high-temperature and high-pressure refrigerant gas discharged from the discharge valve (not shown) of the upper bearing 74 enters the discharge muffler 76 at one end, and is then discharged into the sealed container 72 from the discharge hole of the discharge muffler 76.

  A suction muffler 78 is provided beside the hermetic container 72 to suck low-pressure refrigerant gas from the refrigeration cycle and prevent liquid refrigerant from being directly drawn into the cylinder chamber of the cylinder 79 when the liquid refrigerant returns. The suction muffler 78 is connected to the suction port of the cylinder 79 via the suction pipe 71. The suction muffler 78 is fixed to the side surface of the sealed container 72 by welding or the like.

  FIG. 11 is a cross-sectional view of the shielding plate 80 showing the first embodiment.

  A shielding plate 80 provided with a shielding plate hole 80a (shown in FIG. 11) is provided between the discharge muffler 76 and the permanent magnet motor 100. The shielding plate 80 has a substantially disc shape. The high-temperature and high-pressure refrigerant gas compressed by the compression element 200 is discharged from the discharge hole of the discharge muffler 76, passes through the stator notch 12 c of the permanent magnet motor 100 from the shield plate hole 80 a of the shield plate 80, and is discharged. It is discharged from the pipe 70 to an external refrigerant circuit.

  Nine shielding plate holes 80a of the shielding plate 80 are provided at substantially equal intervals in the circumferential direction on the outer peripheral edge. The shield plate holes 80a of the shield plate 80 correspond to nine stator cutouts 12c provided on the outer peripheral surface of the stator core 12a.

  That is, the shielding plate 80 provided with the shielding plate hole 80a is provided so that the high-temperature and high-pressure refrigerant gas compressed by the compression element 200 is allowed to pass through the stator notch 12c and the passage of the refrigerant gas to the rotor 11 is suppressed.

  By providing the shielding plate 80 and allowing high-temperature and high-pressure refrigerant gas to pass through the outer periphery of the stator 12, it is possible to suppress the rotor 11 from becoming high temperature. That is, the temperature of the permanent magnet 13a provided in the rotor 11 can be lowered.

  As described above, by reducing the temperature of the permanent magnet 13a, it is possible to improve the demagnetization characteristics against the demagnetizing field current, and it is possible to obtain the rotary compressor 300 with improved demagnetization resistance.

  Moreover, if it is the same demagnetizing-field current, the Dy content rate can be reduced, an inexpensive permanent magnet 13a with a low amount of Dy can be used, and an inexpensive rotary compressor 300 can be obtained.

  Further, since the permanent magnet 13a with a low Dy usage amount generally has a high residual magnetic flux density, the current flowing through the winding 20 can be reduced during the operation of the rotary compressor 300, and the highly efficient permanent magnet motor 100 can be reduced. And the rotary compressor 300 can be obtained.

  In particular, in the rotary compressor 300 shown in the present embodiment, the temperature of the permanent magnet 13a can be lowered by the shielding plate 80, and the permanent magnet 13a having a Dy content (weight ratio) of 4% or less can be used. it can. Therefore, the inexpensive and highly efficient permanent magnet motor 100 and the rotary compressor 300 can be obtained.

  By making the number of the shielding plate holes 80a and the stator notches 12c the same number and matching the positions (phases), it becomes possible to pass a high-temperature / high-pressure refrigerant gas through the stator notches 12c, and further effects. Play.

  The high-temperature and high-pressure refrigerant gas compressed by the compression element 200 contains refrigeration oil. However, when the refrigeration oil is taken out of the rotary compressor 300 together with the refrigerant gas, the lubrication failure of the compression element 200 occurs. There are challenges. However, by providing the shielding plate 80 above the discharge muffler 76, the refrigerating machine oil can adhere to the lower portion of the shielding plate 80, and the highly reliable rotary compressor 300 can be obtained.

  Further, a substantially donut-shaped oil shielding plate 84 is provided above the stator 12. Even if the shielding plate 80 is provided, the refrigeration oil may be contained in the refrigerant gas. However, by providing the substantially donut-shaped oil shielding plate 84 above the stator 12, only the highly viscous refrigeration oil contained in the refrigerant gas is provided. Is attached to the oil shielding plate 84, and only the refrigerant gas is discharged from the discharge pipe 70, whereby the rotary compressor 300 with higher reliability can be obtained.

  In FIG. 11, the shape of the shielding plate hole 80 a is a long hole shape, but may be configured in other shapes such as a round hole shape and a trapezoidal shape. In addition, although nine shielding plate holes 80a are provided in accordance with the nine stator cutouts 12c, the number of the shielding plate holes 80a is not limited as long as the positions coincide with the stator cutouts 12c.

  FIGS. 12 to 14 are diagrams showing the first embodiment, and FIG. 12 is a configuration diagram of permanent magnets per pole. FIG. 13 is a perspective view of permanent magnets 13b and 13c divided into permanent magnets 13b and 13c. FIG. 14 is a configuration diagram of permanent magnets per pole, a perspective view of permanent magnets 13d and 13e divided into permanent magnets 13d and 13e, FIG. 14 is a configuration diagram of permanent magnets per pole, and permanent magnets 13f, 13g, It is a perspective view of permanent magnets 13f, 13g, 13h, and 13j divided into 13h and 13j.

  Generally, the permanent magnet motor 100 is operated by an inverter which is a drive circuit shown in FIG. The inverter controls the voltage and frequency applied to the permanent magnet motor 100 by PWM (Pulse Width Modulation) control.

  By performing PWM control, the permanent magnet provided in the rotor 11 of the permanent magnet electric motor 100 is a conductor, so eddy current flows, eddy current loss occurs, and the temperature of the permanent magnet rises.

  In this embodiment, as shown in FIG. 12 to FIG. 14, by dividing the permanent magnet per pole, the eddy current flowing is suppressed by lowering the electrical conductivity of the permanent magnet (increasing the resistivity). The temperature of the permanent magnet can be lowered.

  In the example shown in FIG. 12, the permanent magnet per pole is divided into two in the circumferential direction, and the permanent magnet per pole is divided into a permanent magnet 13b and a permanent magnet 13c.

  In the example shown in FIG. 13, the permanent magnet per pole is divided into two in the axial direction, and the permanent magnet per pole is divided into a permanent magnet 13d and a permanent magnet 13e.

  In the example shown in FIG. 14, the permanent magnet per pole is divided into four in the circumferential direction and the axial direction, and the permanent magnet per pole is divided into a permanent magnet 13f, a permanent magnet 13g, a permanent magnet 13h, and a permanent magnet 13i. is doing.

  By lowering the magnet temperature, a permanent magnet having a low Dy content can be used, and an inexpensive and highly efficient permanent magnet motor 100 and rotary compressor 300 can be obtained.

  In addition, by coating the surface of the permanent magnet with a highly heat-insulating resin or the like, the heat of the rotor core 11a becomes difficult to be transmitted to the permanent magnet, the temperature rise of the permanent magnet can be suppressed, and it is inexpensive and highly efficient. A rotary compressor 300 can be obtained.

  FIG. 15 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 301 of a first modification. Another example of the hermetic compressor will be described with reference to FIG. The rotary compressor 301 of the first modification shown in FIG. 15 is a shield plate 81 having a slope that is higher on the outer peripheral side than the inner peripheral side with respect to the shield plate 80 (substantially horizontal) of the rotary compressor 300 shown in FIG. It is equipped with.

  By providing the shielding plate 81 with a higher inclination on the outer peripheral side than on the inner peripheral side, the flow of the high-temperature and high-pressure refrigerant gas discharged from the discharge muffler 76 becomes smooth, and a highly efficient rotary compressor with reduced pressure loss 301 can be obtained.

  FIG. 16 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 302 of a second modification. The rotary compressor 302 of the second modification shown in FIG. 16 includes a shielding plate 82 that is inclined so that the outer peripheral side is lower than the inner peripheral side.

  By providing the shielding plate 82 that is inclined so that the outer peripheral side is lower than the inner peripheral side, the refrigerating machine oil accumulated on the upper surface of the shielding plate 82 is stopped after the rotary compressor 302 stops, that is, the rotor 11 rotates. After stopping, it passes through the shielding plate hole 82a provided on the outer peripheral side of the shielding plate 82 and falls to the lower surface, so that there is no shortage of refrigerating machine oil and a highly reliable rotary compressor 302 can be obtained.

  FIG. 17 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 303 of a third modification. In the rotary compressor 303 of the third modification, a pipe 83 is passed through the shielding plate hole 80a of the shielding plate 80 of the rotary compressor 300 shown in FIG. 10, and the pipe 83 is stretched to reach the stator notch 12c. It is set.

  By directly connecting the shielding plate hole 80a and the stator cutout 12c with the pipe 83, the high-temperature and high-pressure refrigerant gas compressed by the compression element 200 can more easily pass through the stator cutout 12c. The temperature of the magnet 13a can be lowered, and the inexpensive and highly efficient permanent magnet motor 100 and the rotary compressor 303 can be obtained.

  FIG. 18 shows the first embodiment, and is a longitudinal sectional view of a rotary compressor 304 of a fourth modification. The rotary compressor 304 of Modification 4 is configured such that the refrigerant gas passes through the stator notch 12c by providing a rotation shielding plate 85 directly connected to the rotor 11 on the compression element 200 side.

  By providing the rotation shielding plate 85 directly connected to the rotor 11, it is possible to suppress the refrigerating machine oil having a high viscosity contained in the refrigerant gas from being discharged from the discharge pipe 70, and the highly reliable rotary compressor 304 is provided. Obtainable.

  In general, a rotary compressor has a load pulsation (rotation unevenness) during one rotation, and therefore tends to increase vibration and noise. In the present embodiment, the rotary shielding plate 85 is directly connected to the rotor 11 to increase the inertia of the rotor 11 and to obtain a low-vibration and low-noise rotary compressor 304 that suppresses uneven rotation during one rotation. be able to.

  Next, the drive circuit 1 of the permanent magnet motor 100 will be described. FIG. 19 shows the first embodiment, and is a circuit diagram of the drive circuit 1 of the permanent magnet electric motor 100. AC power is supplied to the drive circuit 1 from a commercial AC power supply 2 provided outside. The AC voltage supplied from the commercial AC power supply 2 is converted into a DC voltage by the rectifier circuit 3. The DC voltage converted by the rectifier circuit 3 is converted to a variable voltage and a variable frequency AC voltage by the inverter main circuit 4 and applied to the permanent magnet motor 100. The permanent magnet motor 100 is driven by variable frequency AC power supplied from the inverter main circuit 4. The rectifier circuit 3 includes a diode bridge that rectifies the voltage of the commercial AC power supply 2, a chopper circuit that boosts the voltage applied from the commercial AC power supply 2, and a smoothing capacitor that smoothes the rectified DC voltage.

  The inverter main circuit 4 is a three-phase bridge inverter circuit, and the switching section of the inverter main circuit 4 includes six IGBTs 6a to 6f (insulated gate bipolar transistors) using silicon carbide (SiC) as an inverter main element, and 6 SiC-SBDs 7a to 7f (Schottky barrier diodes) using SiC as two flywheel diodes (FRD) are provided. The SiC-SBDs 7a to 7f, which are FRDs, are reverse current prevention means for suppressing the counter electromotive force generated when the IGBTs 6a to 6f turn the current from ON to OFF.

  Here, the IGBTs 6a to 6f using SiC and the SiC-SBDs 7a to 7f are IC modules in which each chip is mounted on the same lead frame and molded with epoxy resin. The IGBTs 6a to 6f may be IGBTs using GaN (gallium nitride) instead of IGBTs using SiC, and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) using SiC and GaN instead of IGBTs. Other switching elements may be used.

  Two voltage-dividing resistors 8a and 8b connected in series are provided between the rectifier circuit 3 and the inverter main circuit 4, and the high-voltage DC voltage is reduced by the voltage-dividing circuit using the voltage-dividing resistors 8a and 8b. A DC voltage detector 8 is provided for sampling and holding the electrical signal.

  Current detection elements 30a and 30c that detect currents flowing through the U-phase winding 20a and the W-phase winding 20c of the permanent magnet motor 100 are provided. As the current detection elements 30a and 30c, a direct current transformer (DCCT), an alternating current transformer (ACCT), or the like is used, and an instantaneous value of a current flowing through the U-phase winding 20a and the W-phase winding 20c is detected.

  The rotor position detection unit 10 calculates the rotation position of the rotor 11 of the permanent magnet electric motor 100 from the output signals of the current detection elements 30 a and 30 c, and outputs the position information of the rotor 11 to the output voltage calculation unit 9. Here, the current of two phases of the U-phase winding 20a and the W-phase winding 20c of the permanent magnet motor 100 is detected, but the current of three phases including the current of the V-phase winding 20b is detected. Alternatively, currents for two phases of other combinations may be detected.

  The rotor position detection unit 10 may detect the terminal voltage of the permanent magnet motor 100 and detect the position of the rotor 11 of the permanent magnet motor 100.

  The position information of the rotor 11 detected by the rotor position detection unit 10 is output to the output voltage calculation unit 9. The output voltage calculation unit 9 is optimally applied to the permanent magnet motor 100 based on the command of the target rotational speed N given from the outside of the drive circuit 1 or information on the operating conditions of the apparatus and the position information of the rotor 11. The output voltage of the inverter main circuit 4 is calculated. The output voltage calculation unit 9 outputs the calculated output voltage to the PWM signal generation unit 31. PWM is an abbreviation for Pulse Width Modulation.

  The PWM signal generation unit 31 outputs a PWM signal that becomes the output voltage given from the output voltage calculation unit 9 to the main element drive circuit 4a that drives each of the IGBTs 6a to 6f of the inverter main circuit 4, and the inverter main circuit The four IGBTs 6a to 6f are respectively switched by the main element drive circuit 4a.

  Here, a control method for suppressing the demagnetizing field of the stator 12 will be described. The demagnetizing field of the stator 12 is generated when a large current flows through the winding 20 (the U-phase winding 20a, the V-phase winding 20b, and the W-phase winding 20c) by mistake.

  In the present embodiment, the instantaneous value of the current flowing through the winding 20 is detected, and when the detected instantaneous current value becomes higher than a predetermined current value, the output voltage calculation unit 9 outputs to the PWM signal generation unit 31. Is controlled so that a large current does not flow through the winding 20, and the demagnetization of the permanent magnet 13a due to the demagnetizing field of the stator 12 can be suppressed, and a highly reliable permanent magnet motor. 100 can be obtained.

  Here, the wide band gap semiconductor will be described. Wide bandgap semiconductor is a generic term for semiconductors having a larger bandgap than Si. SiC used in IGBTs 6a to 6f and SiC-SBDs 7a to 7f is one of wide bandgap semiconductors. (GaN), diamond, etc. Furthermore, wide band gap semiconductors, particularly SiC, have higher heat resistance temperature, dielectric breakdown strength, and thermal conductivity than Si.

  The switching element using SiC realizes a low-loss switching element with a simple configuration and can operate at a higher temperature. Therefore, it can be used near a high-temperature electric motor (or equipment that includes an electric motor), and no cooling fan is required, or airflow fins (heat sinks, etc.) can be reduced in size and weight. It becomes.

  Since switching elements and diode elements formed of such SiC (wide band gap semiconductor) have high voltage resistance and high allowable current density, the switching elements and diode elements can be miniaturized. By using the switching elements and diode elements thus made, it is possible to reduce the size of a semiconductor module incorporating these elements.

  Further, since the heat resistance is high, the heat radiation fins of the heat sink can be downsized and the water cooling part can be air cooled, so that the semiconductor module can be further downsized.

  Furthermore, since the power loss is low, it is possible to increase the efficiency of the switching element and the diode element, and further increase the efficiency of the semiconductor module.

  By setting the switching frequency to a high frequency, the AC voltage generated by the inverter main circuit 4 can output an AC voltage that is closer to a sine wave and has less harmonic components.

  The harmonic component of the AC power applied to the permanent magnet motor 100 becomes a torque ripple of the permanent magnet motor 100, and not only vibration and noise increase, but also motor loss (copper loss and iron loss) due to the current of the harmonic component. There is a problem that the efficiency is lowered due to the increase.

  In the present embodiment, by using SiC for the inverter main circuit 4, the switching frequency can be increased with respect to the inverter main circuit using Si, and vibration and noise are low and the permanent magnet motor is highly efficient. 100 can be obtained.

  Moreover, since the eddy current loss which generate | occur | produces in the permanent magnet 13a increases by making a switching frequency high frequency, the temperature of the permanent magnet 13a increased and the subject that the demagnetization characteristic with respect to a demagnetizing field deteriorated occurred.

  In this embodiment, as described above, by dividing the permanent magnet per pole, the specific resistance value of the permanent magnet can be increased and eddy current can be suppressed, so even when the switching frequency is set to a high frequency. The temperature of the permanent magnet can be lowered. As a result, an inexpensive and highly efficient hermetic compressor using a permanent magnet having a low Dy content can be obtained.

  As an application example of the present invention, there is a hermetic compressor equipped with a permanent magnet motor.

  1 drive circuit, 2 commercial AC power supply, 3 rectifier circuit, 4 inverter main circuit, 6a to 6f IGBT, 7a to 7f SiC-SBD, 8 DC voltage detector, 8a voltage dividing resistor, 8b voltage dividing resistor, 9 output voltage calculation Part, 10 rotor position detection part, 11 rotor, 11a rotor core, 11f magnet insertion hole, 11f-1 magnet insertion part, 11f-2 leakage flux suppression hole, 11g shaft hole, 12 stator, 12a stator core 12b Stator slot, 12c Stator notch, 12d Slot opening, 12e Stator teeth, 12f Core back, 12g Insulation, 13a-13i Permanent magnet, 20 windings, 20a U-phase winding, 20b V-phase winding Wire, 20c W phase winding, 30a current detection element, 30c current detection element, 31 PWM signal generator, 40 slit, 60 gap, 70 discharge 71, suction pipe, 72 sealed container, 72a body, 72b upper dish container, 74 upper bearing, 75 lower bearing, 76 discharge muffler, 77 rolling piston, 78 suction muffler, 79 cylinder, 80 shielding plate, 80a shielding plate hole, 81 Shield Plate, 82 Shield Plate, 83 Pipe, 84 Oil Shield Plate, 85 Rotation Shield Plate, 90 Rotating Shaft, 90a Eccentric Shaft, 90b Main Shaft, 90c Subshaft, 100 Permanent Magnet Motor, 200 Compression Element, 300 Rotary Compressor, 301 Rotary compressor, 302 Rotary compressor, 303 Rotary compressor, 304 Rotary compressor

Claims (11)

A sealed container in which refrigerator oil is stored at the bottom;
A compression element provided in the sealed container, compressing the refrigerant, and the sliding portion being lubricated by the refrigerating machine oil;
An electric element that is provided above the compression element in the sealed container, drives the compression element, and has a stator and a rotor that is disposed inside the stator and uses a permanent magnet;
A sealed type comprising: a shielding plate provided above the compression element and below the electric element and guiding the refrigerant discharged from the compression element to the stator of the electric element Compressor. The stator has a plurality of notches on the outer periphery,
The hermetic compressor according to claim 1, wherein the shielding plate includes a plurality of shielding plate holes corresponding to the notches of the stator in an outer peripheral portion.   The hermetic compressor according to claim 2, wherein phases of the shielding plate hole and the stator notch are matched.   The hermetic compressor according to any one of claims 1 to 3, wherein the shielding plate has a substantially disc shape.   The hermetic compressor according to claim 4, wherein the shielding plate is inclined so that the outer peripheral side is higher than the inner peripheral side.   The hermetic compressor according to claim 4, wherein the shielding plate is inclined so that the outer peripheral side is lower than the inner peripheral side.   3. The hermetic compressor according to claim 2, further comprising a pipe that communicates the shielding plate hole with the stator cutout.   3. The hermetic compressor according to claim 2, wherein the shielding plate is constituted by a rotating shielding plate directly connected to the rotor on the compression element side of the rotor.   2. The hermetic compressor according to claim 1, wherein the permanent magnet used in the rotor is a rare earth permanent magnet containing neodymium, iron, boron, and dysprosium.   The hermetic compressor according to claim 9, wherein a content ratio of the dysprosium is 4% or less.   The hermetic compressor according to claim 1, wherein the permanent magnet per pole is divided.

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