JPS61251464A - Brushless motor - Google Patents

Abstract

PURPOSE:To accurately mount a magnetic sensitive element with a very simple work by providing an engaging part for engaging the magnetic sensitive element and a mounting member having an engaging part to be engages with a stator core. CONSTITUTION:When a magnetic sensitive element such as a Hall element 7 is mounted, the engaging projection 8c of a Hall element holder 8 is first engaged with the engaging hole 4d of a stator core 4, the holder 8 and a stator core 4a are positioned, and the element 7 is then inserted into the through hole of the core 4a. Thus, a position between the elements 7 is restricted. Accordingly, the positional relationship between a stator core 4c and the Hall element is not displaced, but the element 7 can be mounted accurately at the optimum mounting position as preset.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a brushless motor that detects the magnetic pole position of a field magnet using a magnetically sensitive element such as a Hall element and is driven based on the detected signal.

[Prior art]

Currently, this type of brushless motor is used in computer peripheral equipment and audio equipment conductive connection equipment. For example, an outer rotor type motor as shown in Fig. 5 is used for rotating magnetic disks. be.

In the figure, l is a motor shaft, 2 is a cylindrical holder rotatably attached around the motor shaft 1 via a bearing 3, and 4 is a stator, which is a stator core made of a laminated iron core fixed to the upper outer periphery of the holder 2. 4a, a plurality of slots 4b formed at equal intervals on the outer circumference thereof, and a drive coil 4C wound around the slots 4b. 5 is the rotor,
It is composed of a cylindrical cup-shaped yoke 5a made of a magnetic material and a field magnet 5b fixed to the inner peripheral surface of the yoke 5a. The center of the yoke 5a is fixed to the upper end of the motor shaft 1 with bolts or the like, and covers the stator 4 above and on the sides at a predetermined distance. The field magnet 5b is made of a cylindrical permanent magnet in which magnetic poles are sequentially reversed in the circumferential direction of the yoke 5a, and its inner circumferential surface faces each slot 4b with a certain gap in between. There is. Reference numeral 6 denotes a circuit board fixed to the flange portion 2a of the holder 2 so as to face the rotor 5, and a predetermined drive electronic circuit is formed on this board 6. 7 is a plurality of Hall elements fixed on the substrate 6;
The slot 4b and the field magnet 5b are arranged at a position where the optimum relative position between the slot 4b and the field magnet 5b can be detected.
The optimum relative position with b is the position where the rotor 5 can generate the maximum torque.

The conventional brushless motor is configured as described above, and when the drive coil 4C of the stator 4 is energized, torque is generated in a certain direction in the rotor 5, causing it to rotate.

This detects the magnetic pole position of the rotor 4 by a Hall element 7 placed opposite to the lower surface of the field magnet 5b of the rotor 5, and operates the electronic circuit of the circuit board 6 based on the output signal of the Hall element 7. , by distributing current to the drive coil 4C located at the position where the maximum torque can be generated.

[Problem that the invention seeks to solve]

In the above-mentioned brushless motor, the board 6 to which the Hall element 7 is attached and the stator 4 are separate members installed at separate positions, so when attaching them to the holder 2, the stator core 4C and the board 6 must be connected. There is a risk that the relative position may shift in the circumferential direction, and the substrate 6 of the Hall element 7 may
Even when attached to the substrate 6, each Hall element 7 is attached to the substrate 6.
It is possible to shift in any direction relative to the

For this reason, conventionally, it has been extremely difficult to increase the accuracy of the relative mounting position between the Hall element 7 and the stator 4 in the assembly process. When the relative positional accuracy between the Hall element 7 and the substrate 6 is low, the distribution of current to the drive coil 4C is
Since the position of the magnetic pole of the rotor 5 deviates from that of the rotor 5, there are problems in that the stability of rotation is decreased, power consumption is increased, and other negative effects occur. Furthermore, when attaching a plurality of Hall elements 7 to the circuit board 6, troublesome positioning with respect to the stator core 4C must be performed each time each Hall element 7 is attached, and the attaching process is extremely complicated.

The present invention was made in view of this problem, and an object of the present invention is to provide a brushless motor in which a plurality of magnetically sensitive elements can be attached to a stator core with high precision, and the process for attaching the same can be simplified.

[Means for solving problems]

A mounting member having a fitting portion for the magnetically sensitive element is provided at a position where the optimal relative position between the slot of the stator core and the field magnet can be detected, and the mounting member is provided with a portion for engaging with the stator core. It is something.

[Effect]

The mounting member of the present invention distributes current to the drive coil to the magnetic pole position of the rotor in order to control the magnetically sensitive element in an accurate position with respect to the slot of the stator core without deviation in the circumferential direction and radial direction. This allows stable rotation to be achieved.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4. Note that the same or equivalent parts as in the above conventional example are given the same reference numerals, and detailed explanation thereof will be omitted.

2 and 3 are diagrams showing a first embodiment of the present invention, and in the figures, 8 is a Hall element holder as a mounting member installed on a circuit board 6 on which a predetermined electronic circuit is formed. be. In this Hall element holder 8, 8a is a holder body made of an insulating material, 8C is a plurality of retaining protrusions as retaining parts formed on this Hall element holder body 8a, and these retaining protrusions 8c are formed on the stator core 4. It is inserted into the plurality of retaining holes 4d without gaps. The formation positions of the plurality of retaining protrusions 8c and the retaining holes 4d through which they are inserted may be shifted in the circumferential direction of the stator 4 as shown in FIG. 2, or radially shifted as shown in FIG. It may be set as appropriate according to the shape of the stator 4, the internal structure of the motor, etc., such as by being shifted in the direction.

Reference numeral 8b denotes a through hole as a fitting portion formed in the Hall element holder main body 8a, and has substantially the same shape as the Hall element 7. Further, the formation position of the through hole 8b is such that the Hall element 7 fitted into the through hole faces the lower surface sb+ of the field magnet 5b with the engaging protrusion 8C engaged with the engaging hole 4d. In addition, the optimum relative position between the slot 4b of the stator 4 and the field magnet 5b, that is, the position where the rotor 5 can generate maximum torque can be detected. Each Hall element 7 is inserted into the through hole 8b so that its sensitive part faces the lower surface 5b of the field magnet 5b, and is connected to the electronic circuit on the substrate 6 located below. Note that the other configurations are the same as the above conventional example.

In the brushless motor having the above configuration, when attaching the Hall element 7, first, each engagement protrusion 8c of the Hall element holder 8 is engaged with each engagement hole 4b of the stator core 4, and the Hall element holder 8 and After positioning with the stator core 4a, the Hall element 7 is attached to the stator core 4a.
Insert into the through hole 4d of a. As a result, each Hall element 7
Their relative positions are also regulated. Therefore, the positional relationship between the stator core 4C and the Hall element 7 will not deviate, and the optimal mounting as preset can be done by accurately positioning the Hall element 7.
can be installed.

Therefore, the distribution of current to the drive coil 4C is also carried out appropriately as preset with respect to the magnetic pole position of the rotor 5, and stable rotation can be obtained.

Furthermore, when attaching the plurality of Hall elements 7, there is no need to perform troublesome positioning work for each Hall element 7, and the assembly process can be simplified.

Further, if the Hall element 7 and the holder 8 are integrated in advance, it is extremely suitable for automating the assembly process.

Furthermore, since the Hall element 7 is surrounded by the holder 8, damage to the Hall element 7 is also prevented.

Next, a second embodiment of the invention will be described.

This second embodiment differs from the first embodiment in which the through hole 8b is formed at a position facing the lower surface 5bl of the field magnet 5 as a fitting portion formed in the Hall element holder main body 8a. As shown in the figure, a notch 8d is provided as a fitting portion at a position facing the inner peripheral surface of the field magnet 5, and the Hall element 7 is fitted into this notch 8d. By fitting into this notch 8d, the position of the Hall element 7 in the circumferential direction and the radial direction is regulated, and the same effect as in the first embodiment can be obtained.

〔effect〕

As explained above, the present invention provides a mounting member having a fitting part for fitting the magnetically sensitive elements and an engaging part for engaging the stator core, so that each magnetically sensitive element can be raised with extremely simple work. It can be mounted with precision, the current can be distributed to the drive coil appropriately with respect to the magnetic pole position of the rotor, and stable rotation can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view showing a first embodiment of the invention;
FIG. 2 is an exploded perspective view of the main part shown in FIG. FIG. 4 is an exploded perspective view of essential parts of a second embodiment of the present invention, and FIG. 5 is a partially sectional side view showing a conventional brushless motor. 4...Stator 4a...Stator core 4b...Slot 4C...Drive coil 5...Rotor 5b. ..... Field magnet 7 ..... Hall element 8 as a magnetic sensing element ..... Hall element holder 8a as a mounting member... Hall element holder body 8C...
・Engagement protrusion

Claims (1)

[Claims] The magnetic poles of the field magnets installed in the rotor are detected by multiple magnetic sensing elements, and current is distributed to the drive coils installed in the slots of the stator core according to signals from the magnetic sensing elements. In the brushless motor, a mounting member is provided with a fitting portion for providing a magnetically sensitive element at a position where the optimal relative position between the slot and the field magnet can be detected, and the stator core and the mounting member are provided. A brushless motor characterized by having an engaging portion.