JP2653930B2 - Electric blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower used as a suction fan of a vacuum cleaner or a ventilation fan of a heating device.

[0002]

2. Description of the Related Art An electric blower of this type includes an inner rotor type brushless motor for rotating a blower fan. Since this brushless motor uses a permanent magnet for the rotor, it is necessary to detect the rotational position of the rotor and to energize predetermined stator windings to switch the phase. For this reason, in the conventional brushless motor, a plurality of magnetic poles are magnetized at predetermined angles on a rotating disk that rotates integrally with the rotor, and a detection sensor using a Hall element is provided at a position facing the rotating disk. The rotation position of the rotor is determined by directly magnetically detecting the switching of the magnetic pole of the turntable with this detection sensor.

A brushless motor for an electric blower has a high driving voltage of 100 V to 200 V and generates a strong magnetic field in the stator. Therefore, the amount of heat generated from the stator is large, and the coil temperature of the stator is 160 ° C. to 180 °.上昇 It may rise to the C position. From this, when a Hall element is used as a detection sensor for detecting the rotational position of the rotor, the guaranteed temperature at which this Hall element operates correctly is:
Since the temperature is generally about 100 ° C., it is necessary to provide the Hall element at a position as far away from the stator as possible to minimize the influence of heat from the stator.

[0004] However, even if the Hall element is moved away from the stator, the location of the Hall element is subject to various restrictions due to the size of the motor and the like. Has its limitations, of course. For this reason, conventionally, a brushless motor in which a temperature sensor for detecting a temperature around the stator is provided on an outer peripheral surface of a case accommodating the stator is known.
In this conventional brushless motor, when the temperature around the stator becomes abnormally high, the drive circuit of the motor is controlled by the output from the temperature sensor, and the rotation of the rotor is stopped or decelerated, thereby preventing overheating of the Hall element. I am holding it down.

[0005]

However, since the blower fan driven by the brushless motor is disposed outside the case, the flow path of the air blown by the blower fan is provided outside the case. Exists. Then, since the temperature sensor is located in the air flow path, the temperature sensor is cooled by the air flowing in the flow path, and the temperature around the stator detected by the temperature sensor and the actual temperature around the stator are reduced. There will be a considerable gap between the temperature in the case.

As a result, the temperature around the stator cannot be detected with high accuracy, and the ambient temperature of the detection sensor may exceed the guaranteed temperature. May become unstable.

The present invention has been made in view of the above circumstances, and it is possible to accurately detect the ambient temperature of a detection sensor. An object is to provide an electric blower in which the rotation of a fan is stabilized.

[0008]

Accordingly, the present invention provides a brushless motor including a stator housed in a case and a rotor inserted inside the stator, and one end of a rotor shaft of the rotor. At the one end of the rotor shaft, a blower fan that rotates integrally with the rotor is provided, and a flow path of air blown by the blower fan is positioned outside the case. In the electric blower, the inside of the case of the motor is divided into a first chamber for accommodating a stator and a second chamber having a closed structure in which the first chamber and the flow path of the air are partitioned. The other end of the rotor shaft is guided to the second chamber, and the other end of the rotor shaft introduced into the second chamber is provided with a rotor position detecting rotor that rotates integrally with the rotor. A turning plate is provided, and in the second chamber, a detection sensor for detecting a rotational position of the rotor from the turning disk, and an ambient temperature of the detecting sensor, A temperature sensor for outputting a control signal to a control circuit for controlling the drive circuit of the motor when the ambient temperature exceeds an allowable limit is provided.

[0009]

According to this structure, the detection sensor for detecting the rotational position of the rotor is housed in the second chamber of the case, which is separated from the first chamber for housing the stator. Therefore, the influence of heat on the detection sensor from the stator side is reduced. Moreover, in the second chamber having the closed structure,
Since the temperature sensor that detects the ambient temperature of the detection sensor is housed, the temperature sensor is not directly exposed to the flow of air sent from the blower fan, eliminating the temperature difference between the temperature sensor installation part and the detection sensor installation part. be able to. At the same time, since the detection sensor and the temperature sensor are housed in the same closed space, a change in the ambient temperature of the detection sensor can be detected sensitively, and the responsiveness of the temperature sensor to the temperature change is significantly improved. Therefore, it is possible to accurately detect the ambient temperature of the detection sensor, and it is possible to reliably prevent thermal damage and malfunction of the detection sensor.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in the drawings.

In FIG. 4, an electric blower indicated by reference numeral 1 is housed in a blower box 2. The interior of the blower box 2 is partitioned by a partition wall 3 into a suction passage 4 having a suction port 4a and a discharge passage 5 having a discharge port 5a. The partition wall 3 has a communication port 6 for communicating the two passages 4 and 5 with each other.
The electric blower 1 is supported at the opening of the communication port 6.

As shown in FIG. 1, the electric blower 1 comprises:
An inner rotor type brushless motor 10 is provided. The brushless motor 10 protrudes into the discharge passage 5 of the blower box 2. The cylindrical case 11 constituting the outer shell of the brushless motor 10 is divided into an upper case 12 and a lower case 13, and these two cases 12, 1
3 are connected by screws 14. A stator 15 is housed inside the case 11. Stator 15
Has a stator core 16 and a winding 17 wound around the stator core 16, and the windings 17 are electrically arranged with a phase difference of 120 °.
It is wound so that three-phase driving can be performed with a driving voltage of 0 V to 200 V.

A rotor 19 is inserted and arranged inside the stator 15. The rotor 19 includes a rotor shaft 20 and a rotor magnet 2 provided on the outer periphery of the rotor shaft 20.
1 and 1. The rotor magnet 21 is located inside the stator core 16, and a plurality of magnetic poles are magnetized at predetermined angles on an outer peripheral portion facing the stator core 16. The upper end of the rotor shaft 20 penetrates through the upper surface wall 12a of the upper case 12 and is led out of the case 11, and the upper surface wall 12a
A ball bearing 22 that rotatably supports the upper end of the “0” is provided.

A boss 23 projects downward from the bottom of the lower case 13. The boss portion 23 has a fitting hole 24 formed therein. The fitting hole 24 is coaxial with the case 11, and a flange portion 25 projecting radially inward is integrally formed at an open end of the fitting hole 24. A cylindrical portion 26 extending downward is coaxially protruded from an outer peripheral portion of a lower end of the boss portion 23.
3 is integrated with the lower case 13.

A bearing holder 28 is fitted in the fitting hole 24 of the boss 23. A through hole 29 through which the lower end of the rotor shaft 20 penetrates is formed at the center of the bearing holder 28, and a ball bearing that rotatably supports the lower end of the rotor shaft 20 inside the through hole 29. 30 are provided. Therefore, the rotor shaft 20 of the rotor 19
The upper and lower ends are supported by the frame 11 via ball bearings 22 and 30, whereby the rotor magnet 21 is coaxially positioned inside the stator core 16.

As the upper and lower ball bearings 22 and 30 for supporting the rotor shaft 20, shield bearings containing grease are used.

The bearing holder 28 and the ball bearing 30 are
The inside of the case 11 is divided into a first chamber 31 for accommodating the stator 15 and the rotor magnet 21 and a second chamber 32 which is partitioned from the first chamber 31. Second room 3
2 is located inside the boss portion 23 and the tubular portion 26, and the open end of the tubular portion 32 is closed by a shield plate 33. The shield plate 33 serves as a bottom plate of the second chamber 32, and seals the second chamber 32 without opening it to the discharge passage 5.

The lower end of the rotor shaft 20 penetrates the ball bearing 30 and is introduced into the second chamber 32. A bracket 35 also serving as a back yoke is coaxially fitted around the lower end of the rotor shaft 20.
On the lower surface of 5, a rotating disk 36 for detecting the rotor position is superposed coaxially. The rotating disk 36 is fastened and fixed to the lower end surface of the rotor shaft 20 via a screw 37, and is configured to rotate integrally with the rotor shaft 20. A plurality of magnetic poles are alternately magnetized at predetermined angles on the turntable 36, and eight magnetic poles are magnetized in the present embodiment because three-phase driving is performed. This turntable 36 and bracket 3
Numeral 5 is located inside the fitting hole 24, and a thrust spring 38 made of a wave washer or the like is sandwiched between the flange portion 25 of the fitting hole 24 and the bearing holder 28. . The thrust spring 38 is mounted on the bearing holder 28.
Is pressed toward the first chamber 31, and the play of the upper and lower ball bearings 22 and 30 is absorbed by the pressing.

The rotor shaft 20 penetrating through the case 11
A centrifugal blower fan 40 is fastened and fixed to the upper end through a nut 41. The periphery of the blower fan 40 is covered by a fan cover 42. The fan cover 42 has a shape in which a lower surface is opened, and this opening portion is fitted to the outer periphery of a flange-shaped support wall 43 protruding from the outer peripheral surface of the upper case 12. At the center of the upper surface of the fan cover 42, an inlet 44 connected to the communication port 6 of the blower box 2 is opened. The suction port 44 faces the rotation center of the blower fan 40, and when the blower fan 40 rotates, the air sucked from the suction port 44 is discharged from the outer periphery of the blower fan 40 into the fan cover 42. You. The support wall 43 that supports the fan cover 42 is provided with an air discharge port 45, and the air discharged into the fan cover 42 passes through the discharge port 45 to a discharge passage located outside the case 11. 5 is blown.

Incidentally, the second chamber 32 of the case 11
Accommodates a circuit board 50. Circuit board 50
Is fastened and fixed to the lower surface of the boss portion 23 of the lower case 13 via a screw 49, and a central portion thereof is close to the lower surface of the rotary disk 36. On the lower surface of the circuit board 50,
A detection sensor 5 positioned at a portion facing the turntable 36 for magnetically detecting the rotational position of the rotor magnet 21.
1 is provided. As the detection sensor 51, for example, a Hall element is used. Since the motor 10 of the present embodiment is driven by three phases, three detection sensors 51 are used. The detection sensors 51 are arranged on the lower surface of the circuit board 50 with a phase difference of 120 ° as shown in FIG. I have. Therefore, the switching of the magnetic pole of the turntable 36 is detected by the detection sensor 51, and the rotational position of the rotor magnet 21 is determined.
Transmits a signal indicating the rotational position of the rotor magnet 21 to the motor drive circuit 52.

On the lower surface of the circuit board 50, a temperature sensor 53 such as a temperature fuse is mounted.
The temperature sensor 53 is for detecting the ambient temperature of the detection sensor 51, and in the second chamber 32,
It is provided at a position adjacent to the detection sensor 51. When the ambient temperature of the detection sensor 51 exceeds the guaranteed temperature of the detection sensor 51, the temperature sensor 53
The control circuit 54 sends a signal indicating an abnormality to the control circuit 54. The control circuit 54 receives a signal from the temperature sensor 53 and stops or reduces the rotation of the brushless motor 10. The motor drive circuit 5
Output to 2.

In the case of the present embodiment, the motor drive circuit 52 and the control circuit 54 are integrated into the blower box 2. To explain the structure, one side surface of the blower box 2 is covered with a cover 57 as shown in FIG. The cover 57 forms a circuit storage room 58 between the cover 57 and one side surface of the blower box 2. The upper part of the circuit storage chamber 58 faces the suction passage 4 via a communication port 59 opened at the upper part of one side of the blower box 2. In the circuit storage room 58,
The printed wiring board 60 is housed. The printed wiring board 60 is supported on one side surface of the blower box 2, and its upper end reaches the communication port 59. A plate-shaped heat sink 61 is attached to the upper end of the printed wiring board 60. The heat sink 61 is connected to the communication port 5.
9, is exposed to the suction passage 4 of the blower box 2 through the air passage 9, and comes into contact with air flowing in the suction passage 4 when the blower fan 40 rotates, so that it is forcibly cooled. Various circuit components 62 constituting the motor drive circuit 52 and the control circuit 53 are mounted on the printed wiring board 60, and the surface of the heat sink 61 facing the circuit storage chamber 58 is provided with the stator 15. The switching element 63 (transistor) of the motor drive circuit 52 for switching the current is attached. The switching element 63 is in surface contact with the heat sink 61.
For this reason, the switching element 63 is
The heat is exchanged with the cold air immediately after flowing into the suction passage 4 through the air passageway 4, and the cooling efficiency of the switching element 63 is enhanced.

In FIG. 3, reference numeral 65 denotes a signal cable for electrically connecting the circuit components 62 and the switching element 63 to the sensors 51 and 53 on the circuit board 50.

According to the blower 1 having such a configuration, the rotor magnet 21 is
Is rotationally detected, and a signal indicating the rotational position is input to the motor drive circuit 52. In the motor drive circuit 52, the winding 17 of the stator 15 is energized in accordance with the rotational position of the rotor magnet 21,
Are sequentially switched, so that the rotor 19
It is continuously driven to rotate at a high speed of 00 rpm or more. Due to the rotation of the rotor 19, the blower fan 40 rotates integrally, and air in the suction passage 4 is sucked into the rotation center of the blower fan 40 through the suction port 44. This air is blown out from the outer periphery of the blower fan 40 into the fan cover 42, and is discharged therefrom through the discharge port 45 of the support wall 43 to the discharge passage 5, along the case 11 of the brushless motor 10 in the discharge passage 5. After flowing, it is discharged to the outside of the blower box 2 through the discharge port 5a.

In the electric blower 1 having the above-described configuration, the detection sensor 51 for detecting the rotational position of the rotor magnet 21 is housed in the second chamber 32 which is partitioned from the stator 15 which generates heat and which is sealed. Therefore, the thermal effect of the stator 15 on the detection sensor 51 is reduced. For this reason, the temperature rise of the detection sensor 51 that is weak to heat such as a Hall element can be suppressed, and the reliability of the operation of the detection sensor 51 increases.

In the sealed second chamber 32,
Since the temperature sensor 53 for detecting the ambient temperature of the detection sensor 51 is accommodated, the temperature sensor 53
It does not need to be directly exposed to the air flow inside. Accordingly, the temperature sensor 53 is not affected by the temperature of the air flowing through the discharge passage 5 of the blower box 2, and the temperature difference between the installation portion of the detection sensor 51 and the installation portion of the temperature sensor 53 can be eliminated.

In addition, a detection sensor 51 and a temperature sensor 53
Are housed in the same closed space adjacent to each other, so that a change in the ambient temperature of the detection sensor 51 can be directly and sensitively detected, and the temperature sensor
3 will be significantly improved. From this, the ambient temperature of the detection sensor 51 can be accurately detected, and when the ambient temperature exceeds the guaranteed temperature of the detection sensor 51, the rotation of the rotor 19 is stopped immediately, or the speed is reduced. Can be migrated. Therefore, thermal destruction and malfunction of the detection sensor 51 can be reliably prevented, and the rotor 19 and, consequently, the blower fan 40 can be prevented.
There is an advantage that the rotation of is stable.

Further, in the above embodiment, the temperature sensor 53 is mounted using the circuit board 50 supporting the detection sensor 51, so that no special parts or mounting portions for supporting the temperature sensor 53 are required. The structure can be simplified accordingly.

In the above-described embodiment, the rotational position of the rotor is magnetically detected using a rotating disk having a plurality of magnetic poles and a Hall element. However, the present invention is not limited to this. A slit may be provided on the rotating disk, and a light emitting diode and a phototransistor may be provided on both sides of the rotating disk to optically detect the rotational position of the rotor.

[0030]

According to the present invention described in detail above, since the temperature sensor does not need to be directly exposed to the flow of air sent by the blower fan, the temperature sensor is not affected by the temperature of the air and can be detected. The temperature difference between the sensor installation part and the temperature sensor installation part can be eliminated. Moreover,
Since the detection sensor and the temperature sensor are housed in the same closed space, a change in the ambient temperature of the detection sensor can be directly and sensitively detected, and the responsiveness to the temperature change is remarkably improved. As a result, since the ambient temperature of the detection sensor can be accurately detected, thermal destruction and malfunction of the detection sensor can be reliably prevented, and there is an advantage that the rotation of the rotor and thus the blower fan is extremely stabilized.

[Brief description of the drawings]

FIG. 1 is an overall sectional view of an electric blower.

FIG. 2 is an enlarged sectional view showing a portion of a second chamber of the brushless motor.

FIG. 3 is a diagram showing a positional relationship between a detection sensor and a temperature sensor on a circuit board.

FIG. 4 is a cross-sectional view showing a state where a brushless motor is incorporated in an air blower box.

FIG. 5 is a diagram showing an arrangement state of switching elements as viewed from the direction of line A in FIG. 4;

[Explanation of symbols]

10 brushless motor, 11 case, 15 stator, 19 rotor, 20 rotor shaft, 31 first chamber,
32: second chamber, 36: turntable, 40: blower fan, 5
1: detection sensor, 52: motor drive circuit, 53: temperature sensor

Claims (1)

(57) [Claims] A brushless motor including a stator housed in a case and a rotor inserted inside the stator, wherein one end of a rotor shaft of the rotor is led out of the case. At one end of the rotor shaft, a blower fan that rotates integrally with the rotor is provided, and a flow path of air blown by the blower fan is arranged inside the case of the motor in an electric blower positioned outside the case. A first chamber containing a stator;
The first chamber and the flow path of the air are divided into two chambers, namely, a second chamber forming a hermetically sealed structure, and the other end of the rotor shaft is guided to the second chamber. The other end of the rotor shaft introduced into the second chamber is provided with a rotating disk for detecting a rotor position which rotates integrally with the rotor, and the second chamber is provided with a rotating disk facing the rotating disk. A detection sensor for detecting the rotational position of the rotor from the controller, and a control circuit for detecting an ambient temperature of the detection sensor and controlling a drive circuit of the motor when the ambient temperature exceeds an allowable limit. An electric blower comprising a temperature sensor for outputting a signal.