JPH10234170A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring pattern which allows a sufficient output to be obtained from a Hall element, installed on a brushless motor and a frequency generator with stability. SOLUTION: A wiring pattern 44 which is connected from a position detecting Hall element 38 inside a circle encircled with a FG pattern (pattern for frequency generation) 34, formed on one side of a printed board 14 to a control element 42, such as an IC outside a FG pattern 34, is focused at a point closer to the center 50, and led out. Thereby the circumferential region of the FG pattern 34 is expanded, and sufficiently high frequency generation output is obtained stably. Further, high position detection output is obtained with stability by placing the Hall element 38 in proximity to the magnetic flux of a magnetized section for driving.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type brushless motor with a frequency power generation pattern (hereinafter referred to as an FG pattern) used for a disk drive or the like.
More specifically, the present invention relates to an improvement of a wiring pattern for an FG pattern and a position detector.

[0002]

2. Description of the Related Art Generally, in an outer rotor type brushless motor having an FG pattern and having a small number of slots such as 12 slots and 16 poles, wiring related to the output of a Hall element is required to improve noise resistance. It is desired that the wiring be as short as possible. Therefore, the wiring of the Hall element is directly connected to the control IC element disposed outside the FG pattern.
It was routed outside the pattern.

That is, as shown in FIG. 4, in the case of a conventional 12-slot, 16-pole brushless motor 110, three Hall elements 111a, 111b, 111c are arranged in the middle of an adjacent stator core 112, and a stator core coil is provided. An FG pattern 114 is formed in an arc shape on a substrate 118 so as to surround the outer periphery of the assembly 113. Although not shown in order to avoid complicating the drawing, the magnetized surface of the frequency power generation magnet mounted on the outer peripheral edge of the rotor that is pivotally supported by the center portion 115 of the stator core coil assembly 113 is positioned immediately above the FG pattern 114. Orbiting with a slight separation distance.

The control IC element 116 of the brushless motor 110 is disposed outside the outer periphery of the FG pattern 114 so that the Hall element 11 located inside the FG pattern 114 can be controlled.
1a, 111b, and 111c are electrically connected to each other by a wiring pattern 117. In this case, the wiring pattern 117 wired from the inside to the outside of the FG pattern 114
The FG pattern 114 cannot be provided within the range.

That is, at least the Hall elements 1 on both sides
The FG pattern 114 cannot be provided within an angle range of 60 ° required as an opening angle between 11a to 111c. Therefore, the range in which the FG pattern 114 can be arranged cannot be larger than 360 ° −60 ° = 300 °. For this reason, there is a drawback that the frequency power generation output decreases and the control accuracy of rotation jitter and the like decreases.

[0006]

In order to solve this drawback, the printed circuit board 118 is provided with a Hall element 111.
a, a wiring pattern 117 relating to 111b, 111c is provided on the back side opposite to the side on which the FG pattern 114 is provided;
Hall elements 111a, 111b, 1
Although a means for connecting to each of 11c is possible, it is not preferable because the number of manufacturing steps and manufacturing costs increase due to through-hole processing. In order to increase the output and bring the magnetized portion for frequency power generation of the rotor close to the surface of the FG pattern 114, it is important to control the manufacturing accuracy in order to make the product performance uniform, and in this case, the manufacturing cost also increases. Invite.

As shown in FIG. 5, the Hall elements 121a,
By gathering the wiring patterns 127 from 121b and 121c to the control IC element 126 at one location, the passage area 128 of the wiring led out of the FG pattern 124 is reduced, and the circumferential angle of the FG pattern 124 can be increased. There is a conventional example. FIG. 5 shows the Hall elements 121a and 121a.
1b and 121c to clarify the connection relationship of the wiring patterns 127.
3 is partially omitted.

However, the arrangement of the Hall elements 121a, 121b, and 121c corresponds to the area of the wiring pattern 127 passing between the inside of the FG pattern 124 and the Hall elements 121a, 121b, and 121c.
As a result of being spaced from the inside of the stator core coil assembly 123 toward the center 125 of the stator core coil assembly 123, the distance from the magnetic field of the driving magnetized portion of the rotor is reduced, and the output amplitude is reduced accordingly. For this reason, the zero cross point of the output waveform becomes ambiguous and the Hall elements 121a, 121b, 121
The position detection accuracy of c decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wiring pattern in an outer rotor type brushless motor with an FG pattern that can obtain a sufficient output from both a Hall element and frequency power generation.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a rotor having a driving magnetized portion and a frequency power generating magnetized portion, and the drive changing with the rotation of the rotor. A position detector for detecting a magnetic flux of the magnetized portion for use, an FG pattern arranged to face the magnetized portion for frequency generation and for detecting a rotation speed of the rotor, and a substrate on which the FG pattern is laid. Brushless motor
The position detector is connected to only a plurality of wiring patterns formed closer to the center of rotation of the rotor inside the outermost point of the position detector, and these wiring patterns are converged at one location to form the FG pattern. Is drawn out to the outside across the space between both ends in the circumferential direction.

In addition, it is preferable that the outermost point of the position detector is located radially outward of the innermost portion of the FG pattern.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wiring pattern of a brushless motor according to the present invention will be described below with reference to the drawings. FIGS. 1 and 2 schematically show a first embodiment of a brushless motor 10 according to the present invention. FIG. 1 is a plan view in which a rotor portion is omitted to avoid complicating the drawing, and FIG. It is the side view which showed the section in section.

In FIGS. 1 and 2, reference numeral 12 denotes a rotating shaft supported by a pair of ball bearings 17 fitted to a bearing holder 16 on a printed circuit board 14 and rotatable integrally with a fixed rotor 18. The rotor 18 includes a driving magnet 20 and a stator core coil assembly 2 which are integrally fixed.
Due to the electromagnetic interaction with the rotating shaft 2, the rotating shaft 12 rotates about the rotating shaft 12. That is, the stator core coil assembly 22 is disposed on the outer periphery of the bearing holder 16, and the driving magnetized portion 28 of the driving magnet 20 is provided so as to face the radially outer peripheral surface 26 of the stator core 24.

An FG pattern 34, which is one element of the frequency generator 32, is provided on the upper surface 30 of the printed circuit board 14. On the surface of the driving magnet 20 facing the FG pattern 34, the FG pattern 34 is provided. A frequency power generating magnetized portion 36, which is the other element, is provided. Further, the brushless motor 10 according to the present invention includes three Hall elements 3 as position detectors in the vicinity of the inside of the rotating orbit of the driving magnet 20.
8 on the same circumference, 30 ° in mechanical angle and 120 ° in electrical angle
, And is arranged in an area where the magnetic flux inside the driving magnet 20 works effectively to perform rotation control by magnetic detection.

FIG. 1 shows a brushless motor 10 constructed as described above, which is laid on one side of a printed circuit board 14.
And an arc-shaped FG pattern 34 at a position facing the frequency generating magnetized portion 36 of the driving magnet 20 provided on the rotor 18.
And three Hall elements 38 provided as position detectors inside the arc-shaped FG pattern 34, and control elements such as ICs provided outside the FG pattern 34 from each of the three Hall elements 38. A portion of a coil wiring pattern 48 for a stator coil 46 and a wiring pattern 44 connected to 42 are shown. Other wiring is omitted to make the drawing easier to see.

As shown in the figure, a wiring pattern 44 from a Hall element 38 connected to a control element 42 such as an IC is focused at a position near a rotation center 50 of the rotor.
It is led out from between the terminals 52 and 54 of the G pattern 34.

As described above, by converging the wiring pattern 44 for the Hall element 38 in a narrow range, the effective portion of the FG pattern 34 includes almost the entire circumference,
By keeping the gap between the surface of the FG pattern 34 and the frequency power magnetized portion 36 of the rotor 18 at an appropriate allowable distance, a sufficiently large frequency power output can be stably obtained.

Moreover, the wiring pattern 44 connected to the Hall element 38 is formed so as to pass through the inside of the Hall element 38, that is, the rotation center 50 side of the rotor 18. That is, each Hall element 38 has two power terminals and two output terminals.
Are all connected only to the wiring pattern 44 formed inside the radially outermost point of the Hall element 38 in the arc drawn by the FG pattern 34. In addition,
The wiring pattern connected to one terminal so that the wiring patterns 44 do not cross each other is wired so as to pass under the main body of the Hall element 38 in the radial direction. These wiring patterns 44 are converged at one place together with the coil wiring patterns 48 connected to the coils 46 of the respective phases, and traverse the space between both ends 52 and 54 of the FG pattern 34 in the circumferential direction. It is led out in the radial direction. As a result, since the wiring pattern 44 is not formed between the outermost point of the Hall element 38 and the FG pattern, the Hall element 38 can be installed very close to the inner edge of the FG pattern 34. Therefore, the arrangement position of the Hall element 38 is changed to the driving magnetized portion 2 of the rotor 38.
8, and a position detection signal having a large amplitude can be stably obtained from the Hall element 38.

Next, a second embodiment of the brushless motor according to the present invention will be described by partially enlarging it in FIG. In the figure, components common to the first embodiment are denoted by the same reference numerals. In this embodiment, in the FG pattern 34, the power generation wire element 56 around which the Hall element 38 is provided is shortened, and the Hall element 3
8 are arranged so that the outermost point of the FG pattern 34 is located radially outside of the innermost portion of the FG pattern 34. As a result, the position of the Hall element 38 is further closer to the driving magnetized portion 28 of the rotor 18, and the output of the Hall element 38 can be significantly improved. The other configuration is the same as that of the first embodiment, and the description is omitted.

As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments, and can be variously modified without departing from the gist thereof. Needless to say. For example, in the above embodiment, the Hall element 3 is used as the position detector.
8 has been described by way of example, but is not limited to a Hall element, and may be any magnetically responsive element that detects a change in a magnetic field, such as a Hall IC, a magnetoresistive element, or a thin-film magnetic head, and converts it into an electric signal. May be used.

[0021]

As described above, in the brushless motor according to the present invention, the FG pattern can be formed on almost the entire circumference, and the position detector is located as close as possible to the driving magnetized portion. Therefore, the accuracy of the output signal from the FG pattern is improved, and the accuracy of the output signal from the position detector is also improved, so that good position detection can be performed and the rotational jitter can be improved. In addition, since a large frequency power output can be obtained, the gap between the surface of the FG pattern and the magnetized portion for frequency power generation of the rotor can be set large accordingly, which facilitates management of dimensional accuracy. As a result, production efficiency can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a first embodiment of a brushless motor according to the present invention.

FIG. 2 is a side view, partially in section, of a first embodiment of the brushless motor according to the present invention.

FIG. 3 is a partially enlarged plan view of a second embodiment of the brushless motor according to the present invention.

FIG. 4 is a schematic plan view showing a conventional wiring pattern.

FIG. 5 is a schematic plan view showing another conventional wiring pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Brushless motor 12 Rotary shaft 14 Printed circuit board 16 Bearing holder 18 Rotor 20 Driving magnet 22 Stator core coil assembly 24 Stator core 26 Outer peripheral surface 28 Driving magnetized part 30 Upper surface 32 Frequency generator 34 FG pattern 36 Frequency generating magnetized part 38 Hall element 42 Control element such as IC 44 Wiring pattern 46 Stator coil 48 Coil wiring pattern 50 Center of rotation 52, 54 (FG pattern) terminal 56 Power generation element

Claims (2)

[Claims] A rotor having a driving magnetized portion and a frequency power generating magnetized portion; a position detector for detecting a magnetic flux of the driving magnetized portion that changes with rotation of the rotor; In a brushless motor including a frequency power generation pattern that is arranged to face the power generation magnetized portion and detects the rotation speed of the rotor, and a board on which the frequency power generation pattern is laid, the position detector includes: In addition to connecting to only a plurality of wiring patterns formed closer to the center of rotation of the rotor inside the outermost point of the position detector, these wiring patterns are concentrated at one location and both ends in the circumferential direction of the frequency power generation pattern. A brushless motor characterized in that it is led to the outside across the gap. 2. The brushless apparatus according to claim 1, wherein an outermost point of the position detector is located radially outward of an innermost portion of the frequency power generation pattern. motor.