KR20020083484A - Permanent Magnet Type Rotating Electric Machine and Compressor Using the Same - Google Patents

Abstract

PURPOSE: To provide a permanent magnet type dynamo-electric machine which is low in noises and a compressor using it. CONSTITUTION: The permanent magnet type dynamo-electric machine has a stator 5, on which an armature winding in a concentrated winding is executed so as to surround a plurality of teeth 8 formed to a stator core, and a rotor 1, in which permanent magnets 2 are housed in a plurality of permanent-magnet inserting holes formed to the rotor core 3. Arcuate sections and linear sections are formed to the teeth inner circumferential surfaces of the stator core, with 3.7<=(b/a)<=4.9 being established, when the width of the teeth is represented by (b) and the radial thickness of both end sections 8a of the front ends of the teeth by (a).

Description

Permanent Magnet Type Rotating Electric Machine and Compressor Using the Same}

The present invention relates to a permanent magnet rotary electric machine in which a rotor is provided with a permanent magnet for a field, and more particularly, to a permanent magnet rotary electric machine mounted to a compressor for an air conditioner, a refrigerator and a freezer.

Conventionally, in these types of permanent magnet rotary electric machines, various measures have been taken to reduce noise, that is, to reduce torque ripple. For example, Japanese Unexamined Patent Publication No. 3-106869 (1991) discloses that in order to reduce torque ripple, the center of the tooth end is formed concentrically with the rotor core, and both ends of the top of the tooth are removed from the rotor. The countermeasure formed by the straight line so that it may move away is disclosed.

As described above in the prior art, although the torque ripple is reduced by dropping both ends of the top of the tooth away from the rotor, however, in order to reduce the noise, it is necessary to significantly reduce the torque ripple, so that simply the top of the tooth Measures to keep both ends away from the rotor are insufficient.

It is an object of the present invention to provide a permanent magnet rotary electric machine having limited noise during rotation.

1 is a cross-sectional structural view of a permanent magnet rotary electric machine showing an embodiment of the present invention,

2 is a simulated flux flow diagram according to an embodiment of the present invention;

3 is a table showing a relationship between a tooth top shape and noise according to an embodiment of the present invention;

4 is a cross-sectional structural view of a compressor according to an embodiment of the present invention.

One feature of the invention is that a plurality of permanent magnet inserts formed in the stator and rotor cores are applied to a plurality of teeth formed on the stator core with each armature winding wound around the plurality of teeth formed on the stator core. In a permanent magnet rotary electric machine including a rotor in which each permanent magnet is accommodated in a hole, two or more kinds of gap faces having different gap intervals are formed on the inner circumferential surface of the stator core, and each tooth is 3.7 &lt; a) ≧ 4.9, where a is the radial thickness of the top of each tooth and b is the width of each tooth.

Another feature of the invention is that a plurality of permanent magnet inserts formed in the stator and rotor core are applied to a plurality of teeth formed on the stator core with each armature winding wound around the plurality of teeth formed on the stator core. In a permanent magnet rotary electric machine including a rotor in which each permanent magnet is accommodated in a hole, the inner circumferential surface of each tooth of the stator core is formed of an arcuate portion and a straight portion, and each tooth is 3.7? b / a) ≧ 4.9, where a is the radial thickness of the tip of each tooth top and b is the width of each tooth.

Another feature of the invention is that a plurality of insertion holes formed in the stator and rotor core are applied to a plurality of teeth formed on the stator core, each armature winding wound around the plurality of teeth formed on the stator core In a permanent magnet rotary electric machine including a rotor in which each permanent magnet is accommodated, the inner circumferential surface of each tooth of the stator core is formed of an arcuate portion and a straight portion, and each tooth is 3.7≤ (b / a) ≥ 4.9, wherein a is the radial thickness of the tip of each tooth top and b is the width of each tooth, as well as an arc on the inner circumferential surface of the tooth of the stator core with respect to the axis center of the rotor. The angle formed by the top is chosen to be smaller than the angle formed by the width of the tooth with respect to the axis center of the rotor.

By constructing the permanent magnet rotary electric machine in the manner as described above, since the shape of the top of the tooth is optimized, a permanent magnet rotary electric machine with reduced noise can thus be provided.

In the following, embodiments of the present invention are described in detail with reference to FIGS. Throughout each figure, like reference numerals refer to like elements. Further, in the present embodiment, a 4-pole-6 slot permanent magnet rotary electric machine is illustrated, but the present invention is not limited to this specific machine.

Figure 1 is a cross-sectional structure of a permanent magnet rotary electric machine showing an embodiment of the present invention, Figure 2 is a simulated flux flow diagram according to an embodiment of the present invention, Figure 3 is a top of the tooth form according to an embodiment of the present invention Noise measurement results for rotating electric machines showing the relationship between noise.

In Fig. 1, the permanent magnet rotary electric machine consists of a stator 5 and a rotor 1, the core of the stator 5 being formed of six pieces of teeth 8 and a core back 6 cores. do. In addition, the rotor core 3 in the rotor 1 is provided with a permanent magnet embedding hole in which the permanent magnet 2 is buried, and the armature windings (not shown) which are intensively wound in each slot 7 of the stator 5. (Not shown) is arranged to surround the tooth (8). In this embodiment, each inner circumferential surface of the teeth 8 is constituted by an arcuate portion and a straight portion, and the gap spacing at the central portion 8b of each tooth 8 is referred to as g1, and each tooth 8 end portion Assuming that the gap interval at 8a is g2, a relationship of g1 < g2 is determined. Further, the axis center of the rotor 1 is O, the angle of the arc shape AB with respect to the axis center O is α, and the angle of the width CD of the tooth with respect to the axis center O is β. In this case, the relationship of α <β is determined.

Now, one of the problems associated with permanent magnet rotary electric machines is the noise of rotation caused by torque ripple. Torque ripple is generated due to the higher harmonic flux in the machine, and if the flux distribution in the machine, that is, the flux distribution in the air gap, is smooth, the torque ripple can be reduced.

Observing the flow of the magnetic flux, as shown in FIG. 2, the magnetic flux Φ entering the stator 5 from the rotor 1 side is each tooth 8 from both ends 8a and the center of the uppermost tooth. In the order of the joint and core bag (6). As described above, there is substantially no magnetic flux entering from the slot opening 9, and the magnetic flux concentrates at both ends 8a and the central portion 8b of the top of the tooth and enters therethrough, thus, the magnetic flux distribution in the air gap. In order to smooth the, it is necessary to limit (reduce) the magnetic flux coming from the end 8a of each tooth top to a predetermined amount. Thus, in order to reduce torque ripple, both ends 8a of the top of each tooth are generally spaced away from the rotor 1 so as to obtain a relationship of g1 < g2, whereby both ends of the top of each tooth ( The magnetic flux coming from 8a) is reduced. However, only the adjustment effect by the gap intervals g1 and g2 is limited, and the noise during rotation cannot be sufficiently reduced.

Therefore, the inventors found that satisfactory results can be obtained if the magnetic flux distribution of the gap is smoothed by appropriately saturating the tip 8a of each tooth top to suppress the magnetic flux coming from the tip 8a of each tooth. It was. That is, the inventors have optimized the ratio between the radial thickness of the joint at the top end of each tooth 8a and the width b of each tooth 8, so that the magnetic flux distribution in the gap can be smoothed and the torque ripple can be greatly reduced. The conclusion was reached.

In view of the above, the inventors experimented using permanent magnet rotary electric machines with different ratios of b / a. The noise measurement results are shown in FIG. The permanent magnet rotary electric machine with low noise during rotation is represented by O table, and the permanent magnet rotary electric machine with high noise is indicated by X table. When the ratio b / a was selected in the range of 3.7 ≦ (b / a) ≦ 4.9, it was observed that noise during rotation was reduced.

From the results of the above experiment, when the ratio b / a exceeds 4.9, the noise is increased because a is small with respect to b, so that the magnetic saturation becomes extremely large at both ends 8a of the top of each tooth. As the magnetic flux coming from both ends 8a at the top of each tooth is significantly limited, the magnetic flux entering the stator 5 from the rotor 1 side is concentrated and smoothed at the center 8b of the top of each tooth. This is because it disturbs the magnetic flux distribution.

On the other hand, if the ratio (b / a) falls below 3.7, the reason for the noise becomes large because a is large with respect to b, and as the magnetic saturation at both ends 8a at the top of each tooth is lowered, g1 And the difference in incoming magnetic flux due to the gap gap between g2 and g2, and the difference in incoming magnetic flux between the both ends 8a and the central portion 8b of the uppermost portion of each tooth is large, which hinders the smooth magnetic flux distribution.

That is, if the ratio b / a is selected in the range of 3.7? (B / a)? 4.9, as the magnetic flux density distribution in the gap becomes smooth, torque ripple is limited and noise is reduced.

In addition, as shown in the figure, when the inner circumferential surface of each tooth 8 is composed of an arc portion and a straight portion, the range of the angle α of the arc portion AB to the axis center O is an important factor. . As a result of some experiments on this, if the angle α is smaller than the angle β of the width CD of the tooth with respect to the axis center O, that is, the noise is further reduced at α <β.

4 is a cross-sectional configuration diagram of a compressor according to one embodiment of the present invention. The compressor has a scroll-shaped lap 12 standing upright on the end plate 11 of the fixed scroll member 10 and another scroll-shaped wrap 15 standing upright on the end plate 14 of the pivoting scroll member 13. ) Is formed in engagement with each other, and the pivoting scroll member 13 pivots with the crankshaft 4 to perform the compression operation. Of the compression chambers 16a, 16b ... formed by the fixed scroll member 10 and the revolving scroll member 13, the chambers placed on the outermost side in the radial direction are both scroll chambers 10, 13 according to the revolving motion. Is displaced to its center, its volume is gradually reduced. When the compression chambers 16a and 16b reach near the center of the scroll chambers 10 and 13, the compressed gas in both compression chambers 16a and 16b is discharged from the outlet 17 in communication with the compression chambers 16a and 16b. Discharged. The discharged compressed gas passes through the gas passage (not shown) provided in the fixed scroll member 10 and the frame 18 to reach the compression vessel 19 under the frame 18, and the compression vessel 19 It is exhausted to the outside of the compressor through the discharge pipe 20 provided on the side wall of the. Further, in the present compressor, the drive motor 21 is sealed in the compression vessel 19, and rotates at a rotational speed controlled by an inverter (not shown) arranged separately to perform the compression operation. In this compressor, the drive motor 21 is a permanent magnet rotary electric machine composed of a stator 5 and a rotor 1.

Further, reference numeral 22 is an armature winding of the stator 5, reference numeral 23 is an oil reservoir, reference numeral 24 is an oil hole, and reference numeral 25 is a sliding bearing.

Since compressors are used as driving sources for air conditioners, refrigerators and freezers, and operate all year round, compressors are the most important products requiring energy saving in view of global warming problems. If a permanent magnet rotary electric machine is used in the drive source, due to the high efficiency of the product, energy savings can be obtained, but the permanent magnet rotary electric machine cannot be used unless it innovatively reduces its noise. However, when the permanent magnet rotary electric machine according to the present invention is used as a driving source, since the noise is small and environmental problems can be solved, a compressor that can obtain high efficiency and energy saving can be provided.

When the compressor using the permanent magnet rotary electric machine according to the present invention is used in an air conditioner as a driving source, it is possible to provide an air conditioner that has passed the top runner regulation.

When a compressor using the permanent magnet rotary electric machine according to the present invention is used in a refrigerator as its driving source, it is possible to provide a refrigerator that has passed top runner regulations.

When a compressor using a permanent magnet rotary electric machine according to the present invention is used in a freezer as its driving source, a freezer that can save energy can be provided.

As described above, according to the present invention, since the noise of the permanent magnet rotating electric machine can be reduced at the time of rotation, the permanent magnet rotating electric machine with reduced noise and a compressor using the same can be provided.

Claims (7)

Each armature winding wound intensively around a plurality of teeth formed on the stator core is inserted into a plurality of permanent magnet insertion holes formed in the stator and rotor cores applied to the plurality of teeth formed on the stator core. In a permanent magnet rotary electric machine comprising a rotor for receiving a permanent magnet, Two or more types of gap faces with different gap spacing are formed on the tooth inner circumferential surface of the stator core, and each tooth is configured to satisfy a relationship of 3.7 &lt; (b / a) &gt; 4.9, where a is the top of each tooth A permanent magnet rotary electric machine, characterized in that the radial joint thickness at the end of b is the width of each tooth. Each armature winding wound around a plurality of teeth formed on the stator core is wound into a plurality of permanent magnet insertion holes formed in the stator and rotor cores applied to the plurality of teeth formed on the stator core. A permanent magnet rotary electric machine comprising a rotor accommodated therein, The inner circumferential surface of each tooth of the stator core is formed to have an arc shape and a straight portion, each tooth is configured to satisfy a relationship of 3.7 ≤ (b / a) ≥ 4.9, where a is the radial direction of the end of each tooth top A joint thickness of b and b is the width of each tooth. The method of claim 2, And an angle formed by an arc shape on the inner circumferential surface of the tooth of the stator core with respect to the axis center of the rotor is selected to be smaller than the angle formed by the width of the tooth with respect to the axis center of the rotor. A compressor comprising the permanent magnet rotary electric machine according to any one of claims 1 to 3 as its drive source. An air conditioner comprising the compressor according to claim 4. Refrigerator comprising a compressor according to claim 4. A freezer comprising the compressor according to claim 4.