JP5178307B2 - Commutator motor and electric blower using the same - Google Patents

Description

  The present invention relates to an iron core of a commutator motor and its structure, and more particularly to a commutator motor mounted on an electric blower and used as a drive source.

  From the viewpoint of operability, electric vacuum cleaners and electric tools are desired to have a small and lightweight motor. As means for reducing the size and weight of the motor, for example, as described in Non-Patent Document 1, a method of setting a high rotational speed and a method of setting the magnetic flux density of the iron core to be relatively high are employed.

  On the other hand, a vacuum cleaner has a suction force as a performance required with a reduction in size and weight. The suction force strongly depends on the output of the electric blower, but since there is a limit to the power that can be supplied to the electric blower in household vacuum cleaners, increasing the motor output by improving the efficiency of the commutator motor is the key to improving the suction force. Therefore, reduction of the loss of the commutator motor is strongly demanded.

  On the other hand, in the commutator motor, an attempt has been made to increase the brush life by reducing the pulsating torque and reducing the mechanical vibration to improve the commutation performance of the motor.

  FIG. 9 shows a cross-sectional configuration of a conventional commutator motor. 1 is a stator, 2 is an armature, 3 is a stator core, 4 is a shaft, 5 is a field winding a, 6 is a field winding b, 7 is an armature core, 8 is a main pole, 10 is an electric machine It is a child winding.

  41 is a stator slot, 42 is an armature slot, and 43 is a tooth.

  As for torque, 5 is wound around the stator core 3 by concentrated winding, 5 is the field winding a, 6 is the main magnetic flux from the field winding b, and armature winding is wound around the armature core 7. It is generated by magnetic interaction with the armature reaction magnetic flux from 10.

  The pulsation torque is generated by a change in magnetic resistance between the stator core 3 and the armature core 7, and the degree of change in the magnetic resistance is greatly influenced by the area of the armature slot 42. In particular, a commutator motor for a vacuum cleaner tends to have a large change in magnetic resistance because a design method is adopted in which a winding space, that is, a slot area is relatively large in terms of motor design in order to reduce the size and weight. For this reason, while emphasizing the suction force, the pulsation torque is left relatively large, and an improvement against a decrease in rectification performance due to mechanical vibration generated by the pulsation torque has not yet been achieved.

  Techniques for reducing the pulsating torque are disclosed in Patent Document 1, Patent Document 2, and Patent Document 3. Hereinafter, these conventional examples will be described.

  Patent Document 1 discloses that the end face on the outer side in the radial direction of the armature teeth is inclined so as to spread forward in the rotational direction, thereby reducing the pulsation torque.

  Patent Document 2 discloses a configuration in which an iron core at the front end of the main pole positioned on the forward side of the main pole with respect to the armature rotation direction is set shorter than that on the reverse side of the armature, and an asymmetric core configuration with respect to the central axis of the commutator motor This is an example. That is, the left and right apertures of the main pole are different from each other with respect to the central axis. Thus, it is disclosed that the influence of the reaction magnetic flux from the armature is suppressed by the asymmetric configuration of the main magnetic pole to reduce the pulsating torque.

  Patent Document 3 discloses an example in which the main magnetic pole is not an asymmetrical iron core shape as compared to Patent Document 2 and an area occupied by the field winding is sufficiently secured.

JP 09-51641 A JP 07-298592 A Japanese Patent Laid-Open No. 2003-153471 RM-96-28, EE-Rotary Machine Study Group “Improvement of power density of universal motor for cleaner”

  The problem to be solved by the present invention is to improve brush life by reducing mechanical vibration that adversely affects commutation performance by reducing pulsation torque while preventing decrease in torque of commutator motor. is there. Ultimately, by improving the brush life while maintaining the suction force, which is the basic performance of a vacuum cleaner, it is possible to achieve a strong suction force and a longer product life.

  The present invention has a stator and an armature, and the stator includes a stator core formed by laminating electromagnetic steel plates, and a field winding wound around the main magnetic pole portion of the stator core. The armature is composed of an armature core formed by laminating electromagnetic steel sheets, an armature winding, a shaft, and a commutator. The armature winding is wound around the slot of the armature core, A commutator motor in which both ends of a child winding are connected to the commutator to transfer power, and a gap gap formed between the inner side of the stator core and the outer diameter of the armature core The length is gradually increased toward the front end of the main magnetic pole of the stator. Further, the rate of the increase is larger on the leading end side of the main magnetic pole of the stator than on the central side of the main magnetic pole of the stator.

  Further, the present invention provides a commutator motor having a bent portion inside the main magnetic pole tip of the stator core, and between the inner side of the stator core and the armature outer diameter from the bent portion toward the main magnetic pole tip. The gap gap to be formed is gradually increased. At that time, the value obtained by dividing the circumferential angle formed by the distance from the bent portion to the main magnetic pole tip by the angle for each armature slot is in the range of 0.4 to 0.7 and the outside of the main magnetic pole tip. The inclination angle in the radial direction is in a range of 5 degrees or more and 15 degrees or less with respect to a tangent line of an arc formed by a gap gap formed between the inner side of the stator core and the outer diameter of the armature.

  In addition, the main magnetic pole tip of the stator core positioned on the reverse side with respect to the rotation direction of the armature is tangent to the arc formed by the gap formed between the inner side of the stator core and the outer diameter of the armature core. On the other hand, it is characterized by inclining in the outer diameter direction. At this time, the rotational driving force of the commutator motor is unidirectional.

  Further, an AC applied voltage is used for driving the commutator motor, and the rotation frequency of the commutator motor is set to 500 Hz or more.

  Furthermore, the commutator motor of the present invention can be used as a drive motor for an electric blower, an electric tool or a vacuum cleaner.

  According to the present invention, by reducing the pulsation torque while maintaining the motor torque, the mechanical vibration can be reduced and the brush life can be dramatically improved, so that a highly efficient and high performance commutator motor can be provided. effective.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 shows a configuration of an electric blower according to the present invention. The motor side of the electric blower 100 includes an armature 2 and a stator 1 in a motor case 60 and an end bracket 62. Further, a diffuser 51 and a fan casing 61 are provided so as to surround the fan 50 provided at the output shaft end of the motor.

  On the other hand, the stator 1 of the motor is formed in a motor case 60, the stator cores 3 and 5 are composed of the field winding a, 6 is composed of the field winding b, and 5 is the field winding a and 6 is the field winding. A main magnetic flux is generated by passing a current through the winding b.

  The armature 2 arranged with the gap gap 15 from the stator core 3 includes a shaft 4 and is supported by a non-output side bearing 21a and an output side bearing 21b provided on the shaft centers of the motor case 60 and the end bracket 62. The shaft 4 is provided with a commutator 35 and an armature core 7, and an armature winding 10 is wound around a slot of the armature core 7, and both ends of each coil are commutations constituting the commutator 35. Connected to the child piece.

  When an AC voltage is applied between the terminals of the commutator motor, the current flows to the carbon brush 31 via one field winding a of the stator 1, and power transfer to the armature 2 is arranged oppositely. This is done via a carbon brush (not shown).

  The energization by the mechanical sliding contact with the commutator 35 is such that the carbon brush is urged to the commutator 35 by the brush pressurizing spring 32 so that stable power can be supplied even under high-speed rotation conditions, and the armature winding 10 is commutated. The electric current accompanying the phenomenon flows and generates continuous torque to obtain the rotational force of the fan.

  FIG. 2 is a cross-sectional view of the commutator motor according to the present invention taken along the line AA. A gap gap 15 formed between the inner side of the stator core 3 and the outer diameter of the armature core 7, the main magnetic pole front end portion 12 of the stator core positioned on the reverse side in the rotational direction of the armature 2 according to the present invention. The structure is inclined in the outer diameter direction with respect to the tangent line L1 of the circular arc formed. The dimension setting for inclining the main magnetic pole tip 12 can be determined in advance from the magnetic flux density distribution in the circumferential direction of the gap gap 15 using a computer described below.

  3 to 5 show analysis values of the magnetic flux density distribution in the air gap of the commutator motor using a computer. FIG. 3 shows a case where 5 is a field winding a, 6 a field winding b, and an armature winding 10 are both energized, and FIG. 4 shows a field winding a and 6 a field winding b only. FIG. 5 shows a case where only the armature winding 10 is excited. The circumferential distribution of the magnetic flux density of the gap gap 15 of the commutator motor according to the present invention is shown for each (a) conventional example and (b) the present invention.

  First, the actual load driving situation will be described with reference to FIG. Since the rotational torque is the product of the magnetic flux density of the gap gap 15 and the motor current, it can be considered that the magnetic flux density of the gap gap 15 affects the rotational torque when the motor current value is regarded as constant. In other words, in order to reduce the pulsating torque, the magnetic flux density distribution of the gap gap 15 may be made sinusoidal. However, in an actual motor, the distribution is not necessarily sinusoidal but distorted due to the influence of the armature reaction magnetic flux. In designing a magnetic circuit of a motor, it should be noted that a distribution with a steep magnetic flux density change should not be taken.

  In the figure, (a) in the conventional example, it can be seen that there is a steep change in the magnetic flux density of the gap 15 at the position of the arrow. Detailed analysis revealed that this is the source of pulsation torque. On the other hand, in the commutator motor according to the present invention, the main magnetic pole tip 12 of the stator core 3 corresponding to this portion is inclined in the outer diameter direction in order to set the steep magnetic flux density gradually. . By setting an appropriate inclination condition of the main magnetic pole tip portion 12, the conventional steep change in magnetic flux density disappears, and as a result, the pulsation torque can be reduced.

  However, if there is little inclination, the effect of this invention will be thin and a problem cannot be solved practically. On the other hand, if the tilt is too large, the equivalent gap length will increase, leading to a decrease in not only the pulsation torque but also the motor torque, so it should be determined after understanding that there is a certain optimum range of tilt conditions. is there.

  4 shows the magnetic flux density distribution of the gap gap 15 when 5 is excited by the field winding a and 6 is excited only by the field winding b. In the case where only the field winding a is excited by 5 and the field winding b is excited by 6 only, the steep change in magnetic flux density in the conventional example shown in FIG. 3 is eliminated in the commutator motor of the present invention. I understand.

  FIG. 5 shows the magnetic flux density distribution of the gap gap 15 when only the armature winding 10 is excited. Similarly, in the case of exciting only the armature winding 10, it can be seen that the steep change in the magnetic flux density in the conventional example shown in FIG. 3 disappears in the commutator motor of the present invention.

  Therefore, in the commutator motor that obtains the rotational driving force by the interaction between the stator magnetomotive force and the armature magnetomotive force, the structure inclined to the outer diameter side provided at the main magnetic pole tip 12 is effective in reducing the pulsating torque. is there.

  6 and 7 show torque waveform analysis values of a commutator motor using a computer. FIG. 6 is a torque waveform of one cycle of alternating current, and FIG. 7 is a waveform obtained by enlarging the torque peak portion. Since the main current (50 Hz in FIGS. 6 and 7) with a commercial frequency of 50 Hz to 60 Hz flows to the motor, the motor torque varies at a cycle of 100 Hz. On the other hand, the pulsation torque is generated at a period corresponding to the armature slot pitch because there is a change in the magnetic resistance between the stator core 3 and the armature core 7 described above. From the knowledge from the magnetic flux density distribution of the gap gap 15, it is clear that the commutator motor according to the present invention can significantly reduce the pulsation torque.

  By the way, the rotational speed is set high in response to the demand for the reduction in size and weight of the commutator motor. For example, the electric blower 100 of this embodiment is rotationally driven at a high speed of 30,000 r / min or more. On the other hand, the carbon brush 31 that plays the role of power transfer while being in sliding contact is subjected to dimensional constraints due to the relationship of the brush life, and due to the mechanical resonance phenomenon that occurs because the elastic frequency and the pulsation torque generation period coincide with each other, Abnormal wear of the carbon brush 31 may be regarded as a problem. The effect of the present invention is more effective in such a case. Particularly, since the commutator motor of the present embodiment has two poles, the effect is further exhibited at a rotational frequency of 500 Hz or more because of the two poles. .

  If the inclined portion of the main magnetic pole tip 12 is arranged at least at one position with respect to one main magnetic pole 8 and on the reverse side with respect to the rotation direction of the armature 2, the effect of the present invention is sufficiently exerted. For this reason, the commutator motor in the present embodiment is assumed to be rotationally driven in one direction of a blower motor mounted on the vacuum cleaner, and the inclined portion of the main pole tip 12 is in the direction of rotation of the armature 2 of the main pole 8. Although only one location is provided on the reverse side, the effect of the invention can be obtained on the reverse side of the armature 2 even if the inclined portion of the main magnetic pole tip 12 is arranged on both the forward side and the reverse side with respect to one main magnetic pole. It will be enjoyed as if it were one place. Further, the arrangement of both the forward side and the reverse side of the inclined portion with respect to the main magnetic pole 8 is effective in reducing the pulsating torque during the bi-directional rotational drive of the commutator motor that obtains the bi-directional rotational drive force in the clockwise and counterclockwise directions. Is played.

  In the present embodiment, a two-pole commutator motor has been described as an example. However, even in the case of four poles or more poles, the rotation of the armature 2 with respect to one main magnetic pole 8 in the case of one-way rotation. The present invention provides an inclined portion at one or both main magnetic pole tip portions 12 on the reverse side with respect to the direction, and in the case of bidirectional rotation, an inclined portion is provided at both main magnetic pole tip portions 12 with respect to one main magnetic pole. There is no change to the basic configuration.

  FIG. 8 shows a relationship diagram between θ2 / armature slot pitch and θ3, motor torque, and brush life. Here, θ2, θ3 and the armature slot pitch will be described with reference to FIG. θ2 is a circumferential angle formed by the distance from the bent portion of the main magnetic pole tip 12 to the main magnetic pole tip, and an arc formed by the gap gap 15 formed between the inner side of the stator core 3 and the outer diameter of the armature core 7. The angle at which the main magnetic pole tip is inclined with respect to the tangent line L1 is θ3. Further, the armature slot pitch refers to an angle between the armature slots 42 as illustrated. In this embodiment, since the number of armature slots 42 is 12, the armature slot pitch is 360 degrees / 12, which is 30 degrees.

  As for the motor torque, it can be seen that when θ2 / armature slot pitch is set large, a decreasing tendency is shown, but when θ3 is set small, the decreasing tendency becomes slow. Further, when the motor torque sharply decreases when θ3 is 20 degrees, the inclination of the main magnetic pole tip 12 is too large, so that the stator slot 41 is narrowed, 5 is the field winding a, and 6 is the field winding. This is because as a result of difficulty in securing the winding space b, the copper loss was increased.

  As described above, regarding the motor torque, θ2 / armature slot pitch and θ3 must be selected and set so as to maintain the motor torque.

  On the other hand, the brush life does not depend on θ3, and θ2 / armature slot pitch has a peak at 0.5, and the improvement amount of the brush life tends to decrease even if it is larger or smaller than 0.5. . Further, when θ3 is 5 degrees, the improvement in brush life is small compared to the conventional commutator motor, but there is no practical problem in consideration of the selection range of θ2 / armature slot pitch at which the motor torque is maintained. .

  Considering both the maintenance of the motor torque and the improvement of the brush life, the range of θ2 / armature slot pitch is preferably 0.4 or more and 0.7 or less indicated by the dotted line in the figure, and θ3 is 5 degrees or more and 15 or less. It can be seen that it may be set in the range below the degree. That is, the main magnetic pole tip 12 may be inclined so that θ2 / armature slot pitch and θ3 satisfy the above range.

  In this embodiment, the improvement amount of the brush life is emphasized, θ2 / armature slot pitch is set to 0.5, and θ3 is set to 10 degrees.

The half section of the electric blower for vacuum cleaners which shows the example of the present invention. The AA sectional view of the commutator motor of the present invention. Magnetic flux density distribution analysis value of gap gap when both field winding and armature winding are excited. Magnetic flux density distribution analysis value of gap gap when only field winding is excited. Magnetic flux density distribution analysis value of gap gap when only armature winding is excited. Torque waveform analysis value (AC 1 period). Torque waveform analysis value (peak expansion). The relationship diagram of θ2 / armature slot pitch and θ3, motor torque and brush life. AA sectional drawing of the commutator motor of a prior art example.

Explanation of symbols

1 Stator 2 Armature 3 Stator Core 4 Shaft 5 Field Winding a
6 Field winding b
7 Armature core 8 Main pole 10 Armature winding 12 Main pole tip 15 Air gap 21a Non-output side bearing 21b Output side bearings 30a, 30b Brush device 31 Carbon brush 32 Brush pressing spring 35 Commutator 41 Stator slot 42 Armature slot 43 Teeth 50 Fan 51 Diffuser 60 Motor case 61 Fan casing 62 End bracket 100 Electric blower

Claims (5)

Having a stator and an armature,
The stator is composed of a stator core formed by laminating electromagnetic steel sheets, and a field winding wound around a main magnetic pole portion of the stator core,
The armature is composed of an armature core formed by laminating electromagnetic steel sheets, an armature winding, a shaft, and a commutator,
A commutator motor that winds the armature winding in a slot of the armature core, connects both ends of the armature winding to the commutator, and transfers power.
The gap length of the gap formed between the inner side of the stator core and the outer diameter of the armature core gradually increases toward the front end of the main magnetic pole of the stator,
There are a plurality of gap lengths in which the rate of gradual increase is greater on the front side of the main pole of the stator than on the center side of the main pole of the stator and the rate of gradual increase is different .
The rotational driving force of the commutator motor is unidirectional,
Only the tip of the main magnetic pole of the stator core located on the reverse side with respect to the rotation direction of the armature is tangent to an arc formed by a gap formed between the inner side of the stator core and the outer diameter of the armature core. On the other hand, the commutator motor is inclined in the outer diameter direction . The commutator motor according to claim 1,
Has a bent portion the stator iron core positioned on the reverse side,
The main magnetic pole tip is a portion from the bent portion to the main magnetic pole tip,
The commutator motor according to claim 1, wherein a value obtained by dividing a circumferential angle formed by a distance from the bent portion to the tip of the main pole by an angle for each armature slot is 0.5 . An electric blower using the commutator motor according to claim 1 as a drive motor. An electric tool using the commutator motor according to claim 1 as a drive motor. A vacuum cleaner comprising the commutator motor according to claim 1 or 2 as a drive motor.

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