JP2001359267A - Position detector and brushless motor equipped with the detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detector, which is low in cost and whose Hall devices do not show reduction in outputs, and to provide a thin position detector. SOLUTION: This position detector has iron plates (1 and 11), printed boards (2 and 12), on which patterns (20) are formed and which are mounted on the iron plates and Hall devices (5, 15 and 25) which are mounted on the patterns of the printed boards. Through-holes (12a) are formed in the printed boards. At least parts of the Hall devices are inserted into the through-holes, or half- punched protrusions (11a) are formed in the iron plates, and the protrusions are inserted into the through-holes to arrange the iron plates and the Hall devices close to each other, so that more magnetic fluxes ca be caught.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting device for a brushless motor, and more particularly to a mounting structure for mounting a position detecting Hall element on a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, a Hall element has been mounted on an iron plate made of SECC in order to obtain position information of a rotor, and a position output of the rotor has been obtained by moving a rotor magnet on the Hall element. However, this method has a disadvantage that processing is complicated and expensive because a pattern is formed on an iron plate. Therefore, there has been proposed a printed circuit board such as a paper phenol board disposed on an iron plate and a pattern formed on the printed board. Hereinafter, description will be made with reference to the drawings. FIG. 3 is a cross-sectional view showing a conventional position detecting device in which a printed board such as a paper phenol board is stacked on an iron plate, a pattern is formed on the printed board, and a Hall element is mounted on the pattern. In the figure, 1 is an iron plate, 2 is a printed circuit board mounted on the iron plate 1,
Reference numeral 3 denotes a land which is electrically connected to the pattern 20 formed on the printed circuit board 2;
Is a resist that covers. 5 is a Hall element, 6 is
Normally, two leads for the input and two for the output are provided as leads of the Hall element 5, and are fixed to the lands 3 by soldering or the like. 7 is, for example, indium antimony (InSb)
Also, elements made of gallium arsenide (GaAs) or the like are electrically connected to corresponding leads 6 from four corners by bonding wires 8. 9 is a magnetic flux collecting plate made of ferrite or the like. Reference numeral 10 denotes a rotor magnet integrally formed with a rotor (not shown).

[0003]

In the position detecting device for a brushless motor constructed as described above, since the pattern is formed on the printed circuit board, it is inexpensive, but the position detecting device is directly attached to the iron plate 1. The distance between the iron plate and the Hall element is greater than the thickness of the printed circuit board (about 0.3 mm).
8 mm), and the output of the Hall element is reduced by that amount. Therefore, a brushless motor using the position detection device also has a weak position detection output, and thus suffers from disadvantages such as difficulty in recognizing position information. Further, there is a disadvantage that the position detecting device becomes thicker by the thickness of the printed circuit board. Therefore, the disadvantage that the brushless motor using the position detecting device also becomes thick is inevitable.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a position detecting device which has a simple structure and does not reduce the output of the Hall element. further,
Another object of the present invention is to provide a brushless motor that can easily recognize position information of a brushless motor using a position detecting device using a Hall element. Still another object of the present invention is to provide a position detecting device which does not become thicker by the entire thickness of the printed circuit board while using the printed circuit board. Still another object of the present invention is to provide a brushless motor that can be reduced in thickness.

[0005]

According to the first aspect of the present invention, a printed circuit board having a pattern formed on an iron plate is overlaid, and a position detection is performed by mounting a Hall element on the pattern on the printed circuit board. In the apparatus, a through-hole is provided in the printed circuit board, and at least a part of the Hall element is inserted into the through-hole, or a half-cut projection is formed in the iron plate, and the projection is inserted into the through-hole. This can be achieved by disposing the iron plate and the Hall element close to each other so that a large amount of magnetic flux can be picked up. According to the second aspect of the present invention,
This can be achieved by a brushless motor provided with the position detecting device according to the first aspect.

[0006]

FIG. 1 is a sectional view showing a first embodiment of the present invention. In the figure, reference numeral 15 denotes a Hall element. The Hall element 15 has indium / antimony (InSb) and gallium arsenide (GaAs) substantially at the center.
s), indium arsenide (InAs) silicon (Si)
And the like. Reference numeral 16 denotes a lead of the Hall element 15, two for normal bias and two for output are provided diagonally (16 a and 16 c, 16 b and 16 d), and a bonding wire 18 (18 a. 18c, 18b and 18d)
Connected by Reference numeral 19 denotes a magnetic flux collecting plate made of ferrite or the like, which is provided near the element 17.
The element 17, the magnetic flux collecting plate 19, the bonding wire 18 and one end of the lead 16 are integrally resin-molded to form the Hall element 15. Reference numeral 12 denotes a printed circuit board such as a paper phenol board having a pattern 20 formed on one surface and a through hole 12a provided at a position where the Hall element 15 is mounted. Reference numeral 13 denotes a land provided at the tip of the pattern 20. The other end of the lead 16 (the foot of the Hall element 15) is placed on the land 13 and fixed by soldering or the like, and is electrically connected. FIG.
In the case where the lead 16 described in (1) is used as a bias lead, the output lead is not shown because it is in a direction orthogonal to these. 14 is pattern 20 and land 1
This is a resist for insulating 3. Reference numeral 11 denotes an iron plate provided below the printed circuit board 12, and a projection 11a is formed by half-blanking at a position corresponding to the through hole, and a tip of the projection 11a contacts or contacts the lower surface of the Hall element 15. Close. Reference numeral 10 denotes a rotor magnet which is disposed to face the Hall element 15 with a slight gap.

As described above, in this embodiment, the through holes 12 a are provided in the printed circuit board 12, so that the printed circuit board 12 is placed on the iron plate 11, but the hole element 15 is located immediately below the Hall element 15. The projection 11 of the iron plate 11 is on the lower surface.
Since a is increased, the output of the Hall element 15 does not decrease. Therefore, an inexpensive brushless motor can be provided.

Next, FIG. 2 is a sectional view showing a second embodiment of the present invention. In the figure, the same parts as those in FIG. 2, reference numeral 1 denotes an iron plate, which is the same as the conventional iron plate shown in FIG. On the iron plate 1, there is a through hole 1
A printed circuit board 12 having 2a is provided. In the second embodiment, the Hall element 25 is provided upside down by being fitted into the through hole 12a. Reference numeral 26 denotes a lead (a leg of the Hall element 25), which is connected to the element 27 by a bonding wire 28. Thus, the Hall element 2
5 is inserted upside down into the through hole 12a, and the free end of the lead 26 is fixed to the land 13 by soldering or the like.

In the second embodiment, the printed circuit board 12
In the case where the Hall element 25 is directly mounted on the iron plate 1 even though the printed circuit board 12 is mounted on the iron plate 1, Therefore, a thin position detecting device can be provided. Therefore, a thin brushless motor can be provided.

[0010]

As described above, according to the present invention, a printed circuit board having a pattern formed on an iron plate is overlaid,
In a position detection device in which a Hall element is mounted on a pattern on a printed board, a half-hollow projection is formed on the iron plate and a through hole is provided in the printed board, and the projection of the iron plate is inserted into the through hole. By arranging the projection and the Hall element close to each other, the position detection is inexpensive and the output of the Hall element 15 does not decrease even though the printed circuit board is mounted on the iron plate. Equipment can be provided. Therefore, in a brushless motor using such a position detecting device, there is an effect that position information can be easily recognized and cheap. In addition, a printed circuit board having a pattern formed on an iron plate is overlaid,
In a position detecting device in which a hall element is mounted on a pattern on a printed board, a through hole is provided in the printed board, and a hole element is inserted into the through hole to provide a thin position detecting device. Further, since a thin position detecting device can be mounted, a brushless motor having a thin overall structure can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional position detecting device.

[Explanation of symbols]

 1,11 Iron plate 2,12 Printed circuit board 3,13 Land 4,14 Resist 5,15,25 Hall element 6,16,26 Lead 7,17,27 Element 8,18,28 Bonding wire 9,19 Magnetic flux collecting plate 10 Rotor magnet

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 11/00 H02K 11/00 CF term (Reference) 2F063 AA02 AA35 BA30 CA35 CA40 DA01 DA05 DB07 DD02 GA52 GA55 GA61 KA02 ZA01 2F077 AA49 CC02 JJ01 JJ08 JJ23 VV01 VV31 WW04 5H019 AA08 BB01 BB05 BB15 BB18 EE08 5H611 AA01 BB01 BB07 BB08 PP05 QQ03 RR02 TT01 UA01

Claims (2)

[Claims] 1. A position detecting device in which a printed circuit board having a pattern formed on an iron plate is overlaid, and a hole element is mounted on the pattern on the printed circuit board. At least a part of the Hall element is inserted into the iron plate, or a half-cut projection is formed on the iron plate, and the projection is inserted into the through hole, and the iron plate and the Hall element are arranged close to each other. , A position detecting device in a brushless motor capable of picking up a large amount of magnetic flux. 2. A brushless motor comprising the position detecting device according to claim 1.