JPH0686523A - Commutator-less motor - Google Patents

Abstract

PURPOSE:To obtain a commutator-less motor with high reliability at a low cost by providing a stator core plate vertically bent in the direction of a circuit substrate to the outermost diameter section of the core plate nearest to the circuit substrate of a stator. CONSTITUTION:A bearing 8 is constituted of sliding bearings 9 and 10 bearing a shaft 3 and an end receiving plate 18 of the shaft 3, and one piece 19 nearest to a circuit substrate 14 of a stator 6 winding a winding 7 on a projection bends the outermost diameter section thereof vertically in the direction of the circuit substrate 14. Even if the end of a permanent magnet 1 of a rotor is extended near to the circuit substrate 14, strong magnetic attraction still occurs in the direction of the circuit substrate 14 by the influence of the bent core plate 19. Accordingly, the movement of the rotor can be controlled by the end receiving plate 18 even if it is not controlled by the end of the sliding bearing 10, and even if the sliding bearing 10 is used, a commutator-less motor having high reliability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor structure of a commutatorless motor.

[0002]

2. Description of the Related Art In recent years, the reliability of various electric and electronic devices has increased, and highly reliable non-commutator motors have been widely used as the power for these devices.

A conventional non-commutator motor will be described below. FIG. 3 shows the structure of a non-commutator motor used in a conventional fan motor for cooling equipment. In FIG. 3, 1 is a permanent magnet, 2 is a frame, 3 is a shaft, and these constitute a rotor. Around the rotor, a load portion 4 to which a fan motor blade 5 is attached is attached by a method such as press fitting. Reference numeral 6 denotes a stator composed of a plurality of core plates, which is installed so as to face the inner peripheral surface of the permanent magnet 1, and a winding 7 is wound around the protrusion thereof.
Reference numeral 8 is a bearing portion composed of two sliding bearings 9 and 10 and several sliding plates 11 and holds the shaft of 3. A retainer 12 is attached to the end of the shaft. A magnetic sensor 13 for detecting the position of the rotor is installed on the substrate 14 near the end face of the permanent magnet 1 together with the current control circuit of the winding 7. Reference numeral 15 is a case of a fan motor that surrounds the blades 5 and holds the bearing portion 8. An oil drainer 16 is attached to the shaft 3 for the purpose of preventing oil scattering from the bearing portion. Also, 17 is a member for the purpose of preventing oil leakage from the bearing portion and is a cap.

The operation of the non-commutator motor having the above structure will be described below.

First, the magnetic sensor 13 detects the end face magnetic flux of the permanent magnet 1 of the rotor and sends a signal corresponding to the magnetic flux to the control circuit section. The control circuit section applies an appropriate current to the winding 7 in order to rotate the rotor in the correct direction in response to this signal. The rotor rotates accordingly. Since the magnetic sensor 13 constantly monitors the movement of the rotor, the rotation of the rotor continues without stopping.

[0006]

However, in the above-mentioned conventional structure, the magnetic sensor 13 has to be located at a position apart from the laminated core to some extent because the winding 7 exists, so that the magnetic flux of the permanent magnet is reduced. In order to detect, it is necessary to extend the end of the permanent magnet 1 of the rotor to the vicinity of the magnetic sensor 13, and naturally the magnetic attraction force of the rotor is in the direction opposite to the circuit board. Therefore, in order to rotate the rotor at a stable position, it is necessary to limit the movement of the rotor at the end surface of the sliding bearing 10. Since the sliding bearing is generally weak against the sliding of the end face, the life of the motor is shortened. Further, in order to prevent this, there is a problem that the bearing needs to be an expensive rolling bearing.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide an inexpensive and highly reliable commutatorless motor.

[0008]

To achieve this object, a commutatorless motor according to the present invention bends an outermost diameter portion of a core plate of a stator, which is closest to a circuit board, substantially perpendicularly to a direction of the circuit board. Has a stator core plate.

[0009]

With this configuration, since the magnetic attraction force of the rotor is in the direction of the circuit board, even if the bearing is a sliding bearing, it is not necessary to limit the movement of the rotor at its end face, and the rotor can be moved at a stable position. It can be rotated.

[0010]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a permanent magnet, 2 is a frame, 3 is a shaft, and forms a rotor. Reference numeral 4 is a load part having blades 5 attached to its outer circumference. Reference numeral 8 is a bearing portion, which is a sliding bearing 9 for supporting the shaft 3.
10 and the end face receiving plate 18 of the shaft 3.
Reference numeral 13 denotes a sensor that detects the position of the rotor, which is installed on the circuit board 14. A stator 6 has a winding 7 wound around the protrusion. Further, one piece 19 of the stator 6 closest to the circuit board 14 has a maximum outer diameter portion bent substantially perpendicularly to the direction of the circuit board 14. Reference numeral 15 is a case of a fan motor that surrounds the blades 5 and holds the bearing portion 8. An oil drainer 16 is attached to the shaft 3 for the purpose of preventing oil scattering from the bearing portion. Also, 1
7 is also a member for the purpose of preventing oil leakage from the bearing portion and is a cap. The cap 17 holds an end face receiving plate 18.

As described above, according to this embodiment, even if the end portion of the permanent magnet 1 of the rotor is extended to the vicinity of the circuit board 14, the core plate 19 which is still bent has a large effect in the direction of the circuit board 14. Since a magnetic attraction force is generated, a sliding bearing 1
End face receiving plate 1 even if the movement of the rotor is not restricted by the 0 end face
8 can be regulated, and the reliability of the sliding bearing 10 is not impaired.

(Embodiment 2) FIG. 2 shows only the bearing portion of another embodiment in which the structure of the bearing portion of FIG. 1 is changed. This is an example of a bearing part in which the rotor side of the bearing member is a rolling bearing and the other one is a sliding bearing. 20 is a rolling bearing, 10 is a sliding bearing, and 21 is a rolling bearing 2.
It is a spacer for allowing the inner ring of 0 to receive the load of the rotor. 3 is a shaft and 2 is a frame. In this case, since the rolling bearing 20 regulates the movement of the rotor, the end face receiving plate is not necessary. Further, since the preload required when using the rolling bearing can be obtained by the strong magnetic attraction force of the rotor toward the circuit board, it is not necessary to use two expensive rolling bearings.

[0014]

As described above, according to the present invention, a large magnetic attraction force to the circuit board side can be obtained by bending one of the laminated cores of the stator closest to the circuit board side substantially perpendicularly to the circuit board side. Therefore, a highly reliable non-commutator motor can be realized even if a sliding bearing is used as the bearing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a commutatorless motor according to a first embodiment.

FIG. 2 is a sectional view of a bearing portion of a commutatorless motor according to a second embodiment.

FIG. 3 is a sectional view of a conventional commutatorless motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet 2 Frame 3 Shaft 4 Load part 5 Blade 6 Stator 7 Winding 8 Bearing part 9,10 Sliding bearing 11 Sliding plate 12 Lockout 13 Magnetic sensor 14 Circuit board 15 Case 16 Oil drain 17 Cap 18 End face receiving plate 19 core plate 20 rolling bearing 21 spacer

Claims (4)

[Claims] 1. An annular permanent magnet that is radially magnetized from an inner diameter to an outer diameter, a frame that surrounds the outer circumference of the permanent magnet, and a shaft that forms the center of rotation of a rotor at one axial end thereof. An annular rotor composed of a member having a mechanism for rotating, and a plurality of core plates inside the rotor having a plurality of protrusions toward the rotor, which are stacked in the axial direction,
In order to rotate the rotor in a certain direction by passing a current through the stator winding, the stator is composed of windings wound around the protrusions of the laminated core so as to generate magnetic flux. A sensor that detects the position of the rotor installed away from the side that holds the shaft of the shaft by the end face magnetic flux of the permanent magnet or the leakage magnetic flux of the inner face, and the current according to the signal of the sensor In a non-commutator motor consisting of a circuit board containing the flow control circuit and a bearing that is installed at the center of the stator and constitutes the center of rotation of the rotor, the outermost diameter part of the core plate closest to the circuit board of the stator is A non-commutator motor that greatly increases the magnetic force that attracts the rotor toward the circuit board by bending it almost perpendicularly to the direction in which the circuit board is located. 2. A non-commutator motor according to claim 1, wherein a plurality of blades are provided on the outer peripheral portion of the rotor, and a ring-shaped case surrounds the blades to form a box-shaped cooling fan. 3. The bearing according to claim 1, wherein the bearing portion is composed of two bearing members, the bearing member on the shaft holding mechanism side of the rotor is a rolling bearing, and the other one is a sliding bearing. No commutator motor. 4. The non-commutator motor according to claim 1, wherein the bearing portion comprises a slide bearing for receiving the outer circumference of the shaft and a slide bearing portion for receiving the tip of the shaft.