JPH09200986A - Permanent magnet dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the improvement of motor efficiency by specifying the material of a balance weight and by short-circuiting the magnetic flux by magnet within the rotor core thereby restricting the flow of magnetic flux regardless of the mounting position of the balance weight on the rotor. SOLUTION: Balance weights 45a and 45b are constituted with a non-magnetic material such as stainless steel. Then, the amount of short-circuited magnetic flux flowing between different magnetic poles after passing though the balance weights 45a and 45b can be reduced even though the balance weights 45a and 45b are arranged and attached to a rotor 27 in such a manner that they stride different magnetic poles at outer peripheral portion of a rotor core 28 by magnets 40, 40,....

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type DC motor, and more particularly to a ballast weight attached to a rotor of a driven device (load device) drivingly connected to the motor to reduce vibration. Belongs to the technical field of structure.

[0002]

2. Description of the Related Art Generally, a compression mechanism of a compressor is provided with an eccentric roller and an eccentric portion such as an eccentric shaft for driving the eccentric roller, and vibration is generated as the eccentric portion rotates. For this reason, conventionally, as disclosed in, for example, Japanese Patent Publication No. 2-33876, in a compressor motor for driving the above-mentioned compression mechanism, a balance weight is integrally attached to the rotor so that the balance weight is integrated. Thus, the vibration during rotation of the eccentric portion of the compression mechanism is canceled to reduce the vibration during operation of the compressor.

[0003]

By the way, a permanent magnet type DC motor in which a permanent magnet is attached to a rotor is integrally formed by a fastening member which axially penetrates a plurality of laminated magnetic plates and has an outer peripheral portion. A rotor core in which a plurality of magnet mounting portions extending in the axial direction are formed, and a magnet that is mounted and fixed to each magnet mounting portion of the rotor core and forms magnetic poles on the outer peripheral portion of the rotor core. However, when attaching the balance weight to the axial end of the rotor,
When the balance weight is attached to the rotor by being arranged so as to straddle different magnetic poles on the outer peripheral portion of the rotor core by the magnet, the following problems occur.

That is, the magnetic flux generated by a pair of magnets adjacent to each other in the circumferential direction in the rotor core originally comes out from the magnetic pole of one of the magnets, passes through the stator core, and then the magnetic pole of the other magnet of the rotor core. However, if the balance weight is arranged so as to straddle different magnetic poles of the rotor core, a part of the magnetic flux emitted from one of the magnets of the rotor core will be on the stator core side. Instead of passing through the balance weight, it flows through the balance weight to reach the magnetic pole of the other magnet. As a result, magnetic flux leakage with respect to the original magnetic flux flow occurs, and the efficiency of the motor decreases.

Particularly, when the balance weight is attached to the rotor by using the fastening member for fastening the magnetic plate of the rotor core, if the fastening member is made of a magnetic material, the fastening member is Although it can be a part of the magnetic flux path flowing between the stator core side and the stator core side, the magnetic flux flowing through the fastening member made of a magnetic material to the balance weight also increases and the magnetic flux leakage becomes remarkable.

The present invention has been made in view of the above problems, and an object thereof is to specify the material of the balance weight so that the magnetic flux generated by the magnet can be generated regardless of the mounting position of the balance weight with respect to the rotor. This makes it difficult for the rotor core to flow due to a short circuit within the rotor core, and to maintain the improvement of motor efficiency.

[0007]

To achieve the above object, in the present invention, the balance weight is made of a non-magnetic material so that the magnetic flux of the rotor core due to the magnet does not flow due to a short circuit inside the balance weight. I did it.

Specifically, according to the invention of claim 1,
As shown in FIG. 3, fastening members (32), (32), ... In which a plurality of magnetic plates are laminated in the axial direction and penetrate in the axial direction.
And a rotor core (28) formed with a plurality of magnet mounting portions (37), (37), ... Having magnets (40), (40), ... Fixed and attached to the portion (37) and forming magnetic poles on the outer peripheral portion of the rotor core (28),
A rotor (27) that is drivingly connected to a driven device (3) having an eccentric portion (8) that is eccentric about the rotation axis, and is attached to at least one end portion in the axial direction of the rotor (27), Balance weights (45a), (45) for canceling the shake due to the rotation of the eccentric part (8) of the driven device (3)
b) is a permanent magnet type DC motor with the premise.

The balance weight (45
a) and (45b) are the magnets (40), (40), ...
The rotor core (28) is attached to the rotor (27) so as to straddle different magnetic poles on the outer periphery of the rotor core (28), and is made of a non-magnetic material.

According to this structure, the balance weight (4
Since 5a) and (45b) are made of a non-magnetic material, the balance weights (45a) and (45b) have different magnetic poles on the outer peripheral portion of the rotor core (28) by the magnets (40), (40) ,. Even if the rotor core (28) is installed so as to be straddled between the rotor core (28) and the rotor core (28),
Balance weights (45a), (45
The magnetic flux flowing through b) is almost eliminated, the magnetic flux leakage between both magnetic poles can be reduced, and the efficiency of the DC motor can be improved and maintained.

According to the second aspect of the invention, the balance weights (45a) and (45b) are the fastening members (32) and (3).
2) is attached to the rotor (27) by. Therefore, the fastening members (32), (32), ... Which integrate the magnetic plates of the rotor core (28) are also used to attach the balance weights (45a), (45b) to the rotor (27). Even if the balance weights (45a) and (45b) are made of a non-magnetic material as described above, the balance weights (45a) and (45b) pass through the fastening members (32), (32), .... The flowing magnetic flux can be reduced.

According to a third aspect of the invention, in the permanent magnet type DC motor of the second aspect of the invention, the fastening members (32),
(32), ... Are made of a magnetic material. Even in this case, the balance weights (45a), (4
Since 5b) is made of a non-magnetic material, although the fastening members (32), (32), ... Are made of magnetic material,
The magnetic flux flowing through the balance weights (45a), (45b) via the fastening members (32), (32), ... Can be reduced.

On the other hand, in the fourth aspect of the invention, similarly, in the permanent magnet type DC motor of the second aspect of the invention, the fastening members (32), (32), ... Are made of a non-magnetic material. And By doing this, the magnets (40), (40),
It becomes more difficult for the magnetic flux from the magnetic fluxes to flow into the balance weights (45a) and (45b) via the fastening members (32), (32), and so that the magnetic flux flowing through the balance weights (45a) and (45b) can be further reduced. .

According to a fifth aspect of the present invention, in the permanent magnet type DC motor of the first, second, third or fourth aspect of the present invention, as shown in FIGS. 6 and 7, the driven device (3) is a compressor (C). Compression mechanism. Therefore, when vibrations due to the rotation of the eccentric portion (8) in the compression mechanism (3) are suppressed by the balance weights (45a), (45b) on the motor side, magnetic flux leakage by the balance weights (45a), (45b). Can be reduced and the efficiency of the compressor DC motor can be increased.

[0015]

FIG. 6 shows a dome type compressor (C) equipped with a permanent magnet type motor according to an embodiment of the present invention, wherein (1) is a vertically extending closed cylindrical dome,
A refrigerant discharge pipe (2) communicating with the inside and outside of the dome (1) is inserted into the upper end of the dome (1) in an airtight manner with its inner end positioned at the center of the upper end of the dome (1). There is.

Further, a compression mechanism (3) (driven device) for sucking the refrigerant gas, compressing it, and then discharging it into the dome (1) is fitted in the lower part of the dome (1). As shown in FIG. 6, the compression mechanism (3) includes three disk-shaped side housings (4) arranged side by side in the vertical direction.
(4), ... and these side housings (4),
(4), ... A housing comprising two annular roller housings (5) and (5) sandwiched in an airtight manner is provided, and a ring-shaped eccentric roller (6) is provided in each roller housing (5). ) Is the adjacent side housing (4),
(4) It is arranged so as to be located between them.

The side housings (4), (4), ...
A rotary shaft (7) extending in the vertical direction is airtightly penetrated through the central part of the rotary shaft (7), and the rotary shaft (7) has a pair of upper and lower crank parts (7a), (7a). 7a)
Respectively rotatably support the eccentric roller (6) by being inserted into the center hole of the eccentric roller (6), and each eccentric roller (6) has its outer peripheral portion on the inner peripheral surface of the roller housing (5). While being in contact with each other, the rotary shaft (7) is rotated about its axis. That is, in this embodiment, the rotary shaft (7)
Each crank part (7a) and each eccentric roller (6) mounted and supported by each crank part (7a) constitute an eccentric part (8) that rotates around the rotation axis of the rotation shaft (7). It

As shown in FIG. 7, a concave groove portion (5a) extending in the vertical direction is formed at a predetermined portion of the inner peripheral surface of each roller housing (5), and the concave groove portion (5a) is notched in the diameter direction. A column-shaped rocking shaft (9) having a blade fitting insertion portion (9a) is supported so as to be rockable with a vertical axis. On the other hand, a plate-shaped blade (10) extending vertically is integrally provided on the outer peripheral surface of each eccentric roller (6), and the tip end of this blade (10) has an inner peripheral surface of the roller housing (5). Is slidably fitted in the blade fitting portion (9a) of the swing shaft (9) in the concave groove portion (5a) of the eccentric roller (6). An arcuate space (11) surrounded by the inner peripheral surface of the roller housing (5) and side housings (4) on both upper and lower sides (11) has two working chambers (12a) on the suction side and a discharge side (12a). 12b). Further, the groove (5a) is formed on the roller housing (5).
The suction port (1
3) and the discharge port (14) are opened, and the suction port (13) is connected to the downstream end of a refrigerant suction pipe (15) penetrating the side wall of the dome (1), and the upstream side of each refrigerant suction pipe (15). The end is connected to the accumulator (47). On the other hand, the discharge port (14) is opened inside the dome (1), and a discharge valve (16) as a check valve composed of a reed valve is arranged in the middle of the discharge port (14), and each eccentricity is increased. Laura (6)
Rotation of the accumulator (24) sucks low-pressure refrigerant gas into the working chambers (12a) and (12b) through the refrigerant suction pipe (15) and the suction port (13), and the refrigerant gas is sucked into the eccentric roller (6). ) Rotation chamber (12a),
After compression due to the volume reduction of (12b), the discharge port (1
4) is discharged into the dome (1) through the discharge valve (16) to increase the internal pressure of the dome (1), and the high pressure refrigerant gas in the dome (1) is passed through the refrigerant discharge pipe (2). It is designed to be discharged outside the dome (1).

The outer peripheral surface of each crank portion (7a) of the rotary shaft (7) and the outer peripheral surface of each rotary shaft (7) above the upper crank portion (7a) and below the lower crank portion (7a). Are provided with lubricating oil discharge holes (17), (17), ...
Is communicated with a lubricating oil passage (not shown) passing through the shaft center of the rotating shaft (7), and the lubricating oil passage is opened to the lower end surface of the rotating shaft (7). After sucking the lubricating oil accumulated in the inner bottom of the dome (1) into the lubricating oil passage of the rotary shaft (7), the lubricating oil is discharged from each lubricating oil discharge hole (17) to the sliding portion of the compression mechanism (3). Supply. A part of the lubricating oil provided for this lubrication is mixed with the refrigerant gas discharged into the dome (1) from the discharge port (14) of the compression mechanism (3) and then discharged.

At the upper end of the dome (1), there is a permanent magnet type DC motor (2) for driving the compression mechanism (3).
1) is fitted with a vertical axis of rotation. The DC motor (21) comprises a stator (22) and a rotor (27) rotatably arranged in the stator (22). The stator (22) is an annular thin plate composed of a large number of electromagnetic steel plates (magnetic plates) in the axial direction (dome (1)
(In the up-and-down direction), and a cylindrical shape in which winding insert portions (not shown), which are integrated by being laminated in the inner peripheral surface and are formed in the inner peripheral surface, are formed at equal intervals in the peripheral direction. A stator core (23) and a stator winding (24u) of three phases of u-phase, v-phase and w-phase, which is provided by being fitted into the winding insertion portion of the inner peripheral surface of the stator core (23). )-(24w). FIG.
, These three-phase windings (24u) to (24
For example, the u-phase winding (24u) of w) is an outer-phase winding located at the radially outer end of the stator core (23),
Inside the outer phase winding (24u), another phase, for example, a v phase winding (24v) is concentrically arranged as a middle phase winding, and inside the middle phase winding (24v), that is, fixed. The remaining, for example, w-phase windings (24w) are concentrically arranged as inner-phase windings at the radially inner end of the child core (23), and each phase winding (24u) to (24w) loops the coil. It consists of four magnetic poles that are bundled into a shape. A coil end, which is an axial end of each magnetic pole coil, projects from the end of the stator core (23) in the same direction, and radially outward as the distance from the end of the stator core (23) increases. Has been bent. In addition, the stator windings (24u) to (24w) of each phase are integrally fixed with a varnish.

As shown in FIG. 5, the outer phase, middle phase, and inner phase windings (24u) to (24w) are connected at one end thereof by a neutral point, while each phase winding is wound. (2
The other ends of 4u) to (24w) are used as power source input terminals. That is, three-phase stator windings (24u) to (24u)
w) is a Y connection, and this three-phase stator winding (2
A rotating magnetic field is generated in the stator core (23) by supplying power to the power input terminals 4u) to (24w).

On the other hand, the rotor (27) is shown in FIGS.
As shown in Fig. 7, a cylindrical rotor core (28) is formed by axially laminating circular thin plates composed of a large number of electromagnetic steel plates (magnetic plates).
And upper and lower end plates (29a), (29) integrally attached to the upper and lower end portions of the rotor core (28), respectively.
b) and four rivet insertion holes (3) penetrating in the axial direction of the rotor core (28).
0), (30), ... Are formed at equal angular intervals in the circumferential direction. Further, four rivet insertion holes (31), (31), ... Are also provided in the end plates (29a), (29b), respectively, in the rivet insertion holes (3) of the rotor core (28).
0), (30), ... Are penetrated. Then, basically, the upper and lower end plates (29a) and (29b) are superposed on the upper and lower end portions of the rotor core (28) so that the respective rivet insertion holes (30) and (31) are aligned and rotated. The fastening rivet (32) (fastening member) is inserted from the lower side into the rivet insertion holes (30) and (31) of the child core (28) and the end plates (29a) and (29b), respectively, and the fastening rivets are inserted. By crimping the upper end of (32), the rotor core (28) and the end plates (29a) and (29b) are moved to 4
They are integrated by book fastening rivets (32), (32), .... As will be described later, spacers (42), (4) are provided above the upper end plate (29a) of the rotor (27).
2), ..., the oil separating plate (43) and the upper balance weight (45a), and the lower balance weight (45b) under the lower end plate (29b) respectively inserts the respective fastening rivets (32). The four fastening rivets (32), (32), ... Are attached to the rotor (27) while inserting the respective fastening rivets (32).
Are integrally fastened.

The rotor core (28) and end plates (29)
a) and (29b) are respectively formed with shaft insertion holes (34) and (35) having the same inner diameter concentrically with each other in the central portions thereof, and these rotation shafts are inserted into the shaft insertion holes (34) and (35). The upper end of (7) is press-fitted and fixed, and the rotor (27) is attached to each eccentric part (8) (each eccentric roller (6)) of the compression mechanism (3) via the rotary shaft (7). Drive-coupled.

The peripheral edge of the rotor core (28) penetrates in the axial direction at positions corresponding to the rivet insertion holes (30), (30), ... And the end plates (29a),
The four magnet insertion portions (37), (37), ... (Magnet attachment portions) having a rectangular cross section which are closed by (29b) are arranged so as to form each square side portion around the shaft insertion hole (34). Voids (38), (38) extending to the outer peripheral edge of the rotor core (28) in the radial direction are provided at both ends in the circumferential direction of each magnet insertion portion (37). A rectangular plate-shaped permanent magnet (40) made of a rare earth magnet is fitted and fixed in each magnet insertion portion (37), and the rotor (27) is of a magnet embedded type. And these four magnets (40), (40), ...
Is a pair of magnets (40) facing each other in the diametrical direction of the rotor core (28), and the magnetic poles of the pair of magnets (40) facing outward in the radial direction of the rotor core are the same magnetic pole, that is, in the circumferential direction. The pair of magnets (40) adjacent to each other are magnetized so that the magnetic poles of the pair of magnets facing outward in the radial direction of the rotor core are opposite to each other, and these four magnets (40), (40) ,. The magnetic poles of the rotor core (28) are alternately formed on the outer peripheral portion of the rotor core (28) by means of the magnets (40), (40) ,. 24u) ~
The compression mechanism (3) rotates the rotor (27) by the interaction with the magnetic flux of the four magnetic poles formed by (24w).
Drive.

Further, a disk-shaped oil separating plate (43) (not shown in FIG. 3) is inserted into the upper end of the rotor (27) by the rivets (32), (32), .... In this state, they are integrally attached to each other by the fastening rivets (32). This oil separating plate (43) is fitted with each rivet (3
2) through which four cylindrical spacers (42), (4
2), ... Interposed by a predetermined distance from the upper end of the rotor (27), that is, the stator winding (24u) to
It is fixed horizontally to the upper coil end of (24w), and the lubricating oil is discharged from the discharge port (14) of the compression mechanism (3) into the dome (1) together with the discharge gas, and the dome (1). When going to the refrigerant discharge pipe (2) at the inner upper end,
The lubricating oil inside the dome (1) is prevented from flowing toward the refrigerant discharge pipe (2) by the oil separating plate (43) which rotates integrally with the rotor (27).

The upper surface of the oil separating plate (43) (rotor (2
7) and the bottom surface of the lower end plate (29b), which is the lower end of the rotor (27), are provided with a pair of upper and lower balance weights (45a) and (45b) in the form of thin plates, respectively. In the state where they are inserted through (32), (32), ..., They are attached integrally by rotation with the respective fastening rivets (32). Both ends of each of the balance weights (45a) and (45b) are formed in a circular shape, and fastening rivets (32) and (32) are inserted into the respective circular portions. Then, as shown in FIG. 1, the upper balance weight (45
a) is a pair of fastening rivets (32), (32) adjacent to each other in the circumferential direction of the rotor (27), and the lower balance weight (45b) is also the other pair of fastening rivets. By (32) and (32), a pair of magnets (40) adjacent to each other in the circumferential direction of the rotor (27),
The upper and lower balance weights (45a) are arranged so as to straddle different magnetic poles of the outer peripheral portion of the rotor core (28) by (40) and are attached to the rotor (27).
When the position of (45b) and the upper and lower eccentric parts (8), (8) of the compression mechanism (3) are aligned in the circumferential direction in a predetermined state, the compressor (C) is operated. , The deflection due to the rotation of the eccentric parts (8) and (8) of the compression mechanism (3) is DC
Balance weights (45a), (4) on the motor (21) side
It is made to cancel by 5b).

A feature of the present invention is that each of the balance weights (45a), (45b) and each fastening rivet (32) is made of a non-magnetic material such as SUS304.

In FIG. 6, reference numeral (25) denotes a power source connecting portion attached to the outer surface of the upper end of the dome (1), which is a DC motor (2
Three terminals (26), (26), ... For connecting three power input lines from a motor control device (not shown) for controlling the operation of 1) are attached. Also,
In FIG. 7, (18) is a stopper that regulates the maximum opening of the discharge valve (16).

The DC motor (21) for the compressor is
After the magnets (40) in the rotor (27) are mounted in the dome (1) of the compressor (C) together with the compression mechanism (3) in the unmagnetized state, the magnets in the unmagnetized state (4
0) is magnetized. To briefly explain this method, the magnets (40) (magnet materials) that are not magnetized in the magnet insertion portions (37) of the rotor core (28) of the rotor (27) of the DC motor (21), respectively. After inserting and fixing, place the end plates (29a) and (29b) on the upper and lower ends,
On the outer surface of the upper end plate (29a), spacers (42), (4
2), the oil separating plate (43) and the upper balance weight (45a) are arranged, and the lower balance weight (45b) is arranged on the outer surface of the lower end plate (29b). 32), (32), ...

Then, the upper and lower balance weights (4
5a) and (45b) in the circumferential direction at the crank portions (7a) and (7a) of the rotary shaft (7), that is, the compression mechanism (3).
Of the rotor (27) with the shaft insertion holes (3) positioned in a predetermined relationship with the upper and lower eccentric parts (8), (8).
4), (35), press fit the upper end of the rotary shaft (7). Then, the stator (22) of the DC motor (21) is fitted and fixed to the upper part inside the dome (1) of the compressor (C), and the rotor (27) is fitted into the stator (22). While inserting the compression mechanism (3) around each crank portion (7a) of the rotary shaft (7), the compression mechanism (3) is fitted in the lower part of the dome (1), and by this, All parts such as (3) and DC motor (21) are mounted in the dome (1). In this state, the dome (1) is, for example, opened at the upper end, and the magnets (40) in the rotor (27) of the DC motor (21) are not magnetized, but other structures are completed. It is almost the same as the compressor (C).

Thereafter, the magnets (40) of the rotor (27) of the DC motor (21) are connected to the stator winding (24).
u) to (24w) are aligned so as to correspond to the magnetic pole positions, and then a magnetizing voltage is applied to the stator windings (24u) to (24w) to apply the same to the windings (24u) to (24w). A magnetizing magnetic field is generated in the rotor, and this magnetic field causes the rotor (27) to
It is sufficient to magnetize the magnets (40) whose positions are matched.

Therefore, in this embodiment, when the DC motor (21) is in operation, one of the pair of magnets (40), (40) adjacent to each other in the circumferential direction of the rotor (27) of the DC motor (21) is used. ) Radially outside the rotor core (2
8) A magnetic flux flowing from the stator core (23) to the other magnet (40) through the outer peripheral portion of the rotor core (28) again toward the stator core (23).
At that time, the upper and lower balance weights (45) integrally attached to the rotor (27) of the DC motor (21).
a) and (45b) are the upper balance weights (45
In a), one pair of fastening rivets (32) and (32) adjacent to each other in the circumferential direction of the rotor (27), and the lower balance weight (45b) similarly to the other pair. A pair of magnets (40) adjacent to each other in the circumferential direction of the rotor (27) by the fastening rivets (32) and (32).
(40) is arranged so as to straddle different magnetic poles on the outer periphery of the rotor core (28).
Part of the magnetic flux flowing between the magnets (40) adjacent to each other in the circumferential direction of (7), (40) is a fastening rivet (32) located on the outer peripheral portion of the rotor core (28) outside the magnet (40),
(32) and the balance weights (45a), (4) fastened by the fastening rivets (32), (32).
5b) and try to short circuit.

However, the upper and lower balance weights (4
5a) and (45b) are both made of a non-magnetic material such as SUS304 steel, and the balance weights (4)
Since the fastening rivets (32) and (32) for fastening 5a) and (45b) to the rotor (27) are also made of a non-magnetic material, even if each balance weight (45a),
(45b) are four magnets (40), (40),
Are arranged so as to straddle different magnetic poles on the outer peripheral portion of the rotor core (28), and each is for integrating the magnetic plates and the end plates (29a), (29b) of the rotor core (28). The fastening rivet (32) is a balance weight (45a),
Even when the rotor core (28) is used also for attaching the (45b) to the rotor (27), a short-circuit magnetic flux flowing between the different magnetic poles in the rotor core (28) through the balance weights (45a) and (45b) is generated. It almost disappears, and the magnetic flux leakage between the two magnetic poles with respect to the original magnetic flux flow can be reduced. As a result, the efficiency of the DC motor (21) during the operation of the compressor (C) can be improved and maintained.

In the above embodiment, not only the balance weights (45a) and (45b) of the rotor (27) but also the fastening rivets (32) are made of a non-magnetic material. It is also possible that only 45a) and (45b) are made of a non-magnetic material and the fastening rivet (32) is made of a magnetic material. In this way, the rivet insertion holes (30) of the rotor core (28) are replaced by the magnetic material rivets (32).
Since the rotor core (28) has no rivet insertion hole (30) and is made of the magnetic material, the magnetic flux density passing through the rotor core (28) is increased. be able to. However, in order to prevent the magnetic flux from being short-circuited to the balance weights (45a) and (45b) as much as possible, the balance weights (45a) and (45b) and the fastening rivets (32) as in the above embodiment. It is preferable that both of the above) are non-magnetic materials.

Further, in the above embodiment, the rotor (27)
The oil separating plate (43) is arranged at the upper end of the rotor with a space, and the upper balance weight (45a) is mounted on the oil separating plate (43). However, the present invention is applicable to a rotor to which the oil separating plate (43) is not mounted. Can also be applied. In that case, the upper balance weight (45a) is directly attached to the upper surface of the upper end plate (29a).
It is sufficient to attach a).

In the above embodiment, the rotor core (2
8) Fastening rivets (32), (32), for fastening and integrating the circular thin plate and the end plates (29a), (29b).
The balance weights (45a) and (45b) are fastened to the rotor (27) by the
5a), (45b) to the rotor (2
It may be attached to 7), and the same effects as those of the above embodiment can be obtained.

Furthermore, in the above embodiment, each magnet (40) of the rotor (27) in the DC motor (21) is a rare earth magnet, but the present invention provides a rotor to which other ferrite magnets are attached. It can also be applied to a DC motor that has it. Further, according to the present invention, as in the above embodiment, in addition to the embedded DC motor (21) in which the magnet (40) is embedded in the rotor core (28), the magnet is attached to the surface of the rotor core. Any other permanent magnet type DC motor, such as a surface type DC motor, can be applied. Furthermore, it goes without saying that the present invention can be applied to ordinary DC motors other than compressor DC motors.

[0038]

As described above, according to the first aspect of the present invention, the balance weight for canceling the shake due to the rotation of the eccentric portion of the driven device drivingly connected to the rotor is rotated to the rotor having the permanent magnet. Permanent magnet type DC attached integrally
Since the balance weight is made of a non-magnetic material with respect to the motor, even if the balance weight is arranged and attached to the rotor so as to straddle different magnetic poles of the rotor core outer peripheral portion by the magnet, The magnetic flux flowing between the different magnetic poles inside the rotor itself through the balance weight can be reduced, and the magnetic flux leakage between both magnetic poles can be reduced, so that the efficiency of the permanent magnet type DC motor can be improved and maintained.

According to the second aspect of the present invention, the balance weight is attached to the rotor by a fastening member that integrates the magnetic plate of the rotor core. Even if it is attached to the rotor, the magnetic flux flowing through the balance weight through this fastening member can be reduced, and the efficiency of the permanent magnet type DC motor can be improved and maintained.

According to the invention of claim 3, since the fastening member is made of a magnetic material, the magnetic flux flowing through the balance weight through the fastening member is made smaller by the balance weight of the non-magnetic material, and the efficiency of the DC motor is improved. It is possible to maintain improvement.

According to the invention of claim 4, since the fastening member is made of a non-magnetic material, it is possible to further reduce the leakage of the magnetic flux from the magnet flowing through the fastening member to the balance weight, and to improve the efficiency of the permanent magnet type DC motor. It is possible to further improve and maintain the above.

According to the fifth aspect of the present invention, the driven device is the compression mechanism of the compressor, so that when the vibration accompanying the rotation of the eccentric portion of the compression mechanism is suppressed by the balance weight on the motor side, the balance weight is reduced. It is possible to reduce the leakage of magnetic flux due to, and to improve and maintain the efficiency of the compressor DC motor.

[Brief description of drawings]

FIG. 1 is a plan view showing how a balance weight is attached to a rotor in an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing how a balance weight is attached to a rotor.

FIG. 3 is an exploded perspective view showing a configuration of a rotor.

FIG. 4 is a plan view showing an arrangement state of windings in a stator.

FIG. 5 is an electric circuit diagram showing a stator winding of a DC motor.

FIG. 6 is a cross-sectional view showing a compressor equipped with a DC motor according to an embodiment of the present invention.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

[Explanation of symbols]

 (C) Compressor (3) Compression mechanism (driven device) (6) Eccentric roller (7) Rotating shaft (7a) Crank part (8) Eccentric part (21) DC motor (22) Stator (27) Rotor (28) Rotor core (29a), (29b) End plate (32) Fastening rivet (fastening member) (37) Magnet insertion part (magnet mounting part) (40) Magnet (45a), (45b) Balance weight

Claims (5)

[Claims] 1. A plurality of magnet mounting portions, each having a plurality of magnetic plates laminated in the axial direction and integrated by fastening members (32), (32), ... (37), (37), ... Formed rotor core (2
8) and each magnet mounting portion (37) of the rotor core (28)
Driven and having an eccentric part (8) eccentric about the rotation axis, which has magnets (40), (40), ... A rotor (27) drivingly connected to the device (3) and a runout caused by rotation of an eccentric part (8) of the driven device (3), which is attached to at least one end of the rotor (27) in the axial direction. Balance weight (45a) to cancel the
In the permanent magnet type DC motor including (45b), the balance weights (45a), (45b) are rotor cores (28) formed by the magnets (40), (40) ,.
A permanent magnet type DC motor, which is arranged so as to straddle different magnetic poles on the outer peripheral portion, is attached to a rotor (27), and is made of a non-magnetic material. 2. The permanent magnet DC motor according to claim 1, wherein the balance weights (45a), (45b) are attached to the rotor (27) by fastening members (32), (32), .... A permanent magnet DC motor characterized in that 3. The permanent magnet DC motor according to claim 2, wherein the fastening members (32), (32), ... Are made of a magnetic material. 4. The permanent magnet DC motor according to claim 2, wherein the fastening members (32), (32), ... Are made of a non-magnetic material. 5. The permanent magnet type DC motor according to claim 1, 2, 3 or 4, wherein the driven device (3) is a compression mechanism of a compressor (C). motor.