JPH0433558A - Brushless motor - Google Patents

Abstract

PURPOSE:To reduce the number of components and to improve an assembling efficiency by securing a printed circuit board to the base securing part of a mounting base so as to be disposed at its rear side as seen from the end face side of a rotor, and integrally molding an element holder for holding to contain a magnetic element at the base. CONSTITUTION:Three Hall ICs 23 of magnetic detectors for detecting the rotating position of a rotor 19 and a printed circuit board 24 in which the terminals of the ICs 23 are soldered are arranged in a front frame 12 of a motor shell. In a mounting base 25 for mounting the board 24, a board container 29 for containing the board 24 is integrally molded so as to protrude to the rotor 19 side, and the board 24 is contained in the container 29 so as to be disposed at its rear side as seen from the end face side of the rotor 19. Thus, the detector can be held even without preparing a separate holder.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention provides a magnetic detection element for detecting the rotational position of a rotor, which is disposed on a printed wiring board, and this printed wiring board is attached to a motor outer shell. This invention relates to a brushless motor installed inside the motor.

(Prior Art) Conventionally, in brushless motors, for example, the 11th
As shown in the figure, in order to detect the rotational position of the rotor 1, a Hall IC 3, for example, is placed as a magnetic detection element at a position where leakage magnetic flux of the rotor magnet 2 is detected.

This Hall IC 3 is fixed by soldering terminals 3 a to a printed wiring board 4 , and the printed wiring board 4 is fixed to a motor outer shell 6 with screws via a mounting base 5 . Further, the tip of the signal line 7 for taking out the signal from the Hall IC 3 is soldered to the printer I/wiring board 4, and is led out from there through the gap outside the stator coil 8 from the signal line lead-out hole 9 of the motor outer shell 6. It is.

(Problems to be Solved by the Invention) In the conventional configuration described above, the Hall IC 3 is supported by the terminal 3a, so the terminal 3a may bend due to impact during assembly or during transportation after assembly, causing the Hall IC 3 to bend. There is a risk of positional deviation, and there is a drawback that rotation detection accuracy tends to deteriorate.

Therefore, in order to eliminate such drawbacks, a holder (not shown) for holding the Hall IC 3 is attached to the printed wiring board 4, but if this is done, the number of parts increases. This method has the drawbacks of lower assembly efficiency and higher costs.

Furthermore, in the above conventional configuration, since the signal line 7 of the pole IC 3 is loose inside the motor outer shell 6, the signal line 7 may be pushed into the motor outer shell 6 by an external force and come into contact with the rotor 1. , or an excessive tensile force may be applied from the outside to the solder (=I) portion of the signal line 7, which may lead to breakage of the signal line 6, poor connection, etc., resulting in a lack of reliability.

Therefore, in order to eliminate this drawback, we separately installed the signal line 7.
There is a motor equipped with a presser (not shown) that presses and fixes it to the inner surface of the motor outer shell 6, but this method has the disadvantage that the number of parts increases, assembly efficiency decreases, and costs increase. There is.

The present invention has been made in consideration of these circumstances, and a first object thereof is to provide a brushless motor that can improve the positional accuracy of a magnetic detection element without increasing the number of parts or reducing assembly efficiency. In addition to this, a second object of the present invention is to provide a brushless motor that can hold the signal line of a magnetic detection element within the motor outer shell without requiring a separate member.
The purpose of

[Structure of the Invention] (Means for Solving the Problems) A brushless motor according to claim 1 is characterized in that a magnetic detection element for detecting the rotational position of the rotor is disposed on a printed wiring board, and the printed wiring board is mounted on a plastic mounting board. A base for fixing the mounting base to the motor outer shell, the base being disposed in the motor outer shell via a base so that the magnetic detection element is located near the end face of the rotor. A fixing part, a board fixing part for fixing the printed wiring board so as to be positioned on the back side of the rotor when viewed from an end face side of the rotor, and an element holding part for storing and holding the magnetic detection element on the mounting base. It is integrally molded.

Furthermore, in addition to the above-mentioned configuration, the brushless motor of claim 2 further includes a signal line accommodating part in which the signal line of the magnetic detection element is housed between the printed wiring board and the mounting base, and a signal line accommodating part for accommodating the signal line of the magnetic detection element between the printed wiring board and the motor outer shell from the signal line accommodating part. A signal line guide part that guides the signal line toward the signal line lead-out hole of the motor and holds the signal line between the motor outer shell and the signal line guide part is integrally molded.

(Function) The configuration of claim 1 is different from the conventional one in that the printed wiring board is fixed to the board fixing part of the mounting base so as to be positioned on the back side when viewed from the end face side of the rotor. , in that an element holding part for housing and holding the magnetic detection element is integrally molded on the mounting base. in this case,
If the printed wiring board is mounted on the mounting base so that it faces the end surface of the rotor as in the past,
Since the mounting base and the magnetic detection element are separated by the printed wiring board, it is impossible to have a structure in which the element holding part is integrally molded on the mounting base. If the printed wiring board is fixed to the mounting base so as to be positioned on the back side of the rotor when viewed from the end face side of the rotor, the element holding portion can be integrally molded on the mounting base. This makes it possible to hold the magnetic sensing element without having to prepare a separate holder for the magnetic sensing element.
The positional accuracy of the magnetic detection element can be improved without increasing the number of parts or reducing assembly efficiency.

Furthermore, according to the structure of claim 2, since the signal line storage section and the signal line guide section are also integrally molded on the mounting base, one mounting base eliminates the need for separate members. It is also possible to hold the motor inside the motor shell.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 10.

First, the overall general structure will be explained based on FIGS. 3 to 5. The motor outer shell 11 has a stator core 14 sandwiched between a front frame 12 and a rear frame 13, and these three frames are connected by rivets. 15. The stator coil 16 is installed in the slot (not shown) of the stator core 14, and the sunrise wire 16a (see FIG. 4) of the stator coil 16 is inserted into the lead wire outlet hole formed on the side surface of the rear frame 13. 13b to the outside. On the other hand, ball bearings 17.18 are fitted into the cylindrical parts 12a and 13a formed at the center of the front and rear frames 12.13, and the rotor 19 is rotated by these ball bearings 1.7 and 1.8. A shaft 20 is inserted and supported. A rotor core 21 is fitted onto the rotating shaft 20, and a rotor magnet 22 fitted onto the outer circumferential portion of the rotor core 21 faces the inner circumferential surface of the stator core 14.

In the front frame 12, there are three Hall ICs 2B (see FIG. 3), which are magnetic detection elements for detecting the rotational position of the rotor 19, and a printed wiring board to which the terminals of each Hall IC 2B are soldered. 24 are arranged as follows. That is, the plastic mounting base 25 on which the printed wiring board 24 is mounted is formed in a generally semicircular shape as a whole, as shown in FIG. A boss 26 is formed, and a screw insertion hole 27 of the front frame 12 is formed as shown in FIG.
The mounting base 25 is fixed to the front frame 2 by tightening the screw 28 inserted into the screw boss 26. This mounting base 25 is integrally molded with a semicircular arc-shaped board accommodating part 29 for accommodating a printed wiring board 24 formed in a semicircular arc shape so as to protrude toward the rotor 19 side. For printed wiring board 2
4 is housed so as to be located on the back side when viewed from the end surface side of the rotor 19. The specific fixing structure is the board storage part 2.
9 are formed with screw bosses 30 serving as board support parts, for example, and screws 31 inserted into the screw insertion holes 24a (see FIG. 1) of the printed wiring board 24 are tightened to the screw bosses 30. The printed wiring board 24 fixed in this way is attached to the screw boss 3 when viewed from the end surface side of the rotor 19.
0 (substrate support part).

In order to facilitate positioning of the printed wiring board 24 when installing the printed wiring board 24, the board storage section 2
The printed wiring board 24 is positioned by integrally molding positioning pins 32 at, for example, two locations on the printed wiring board 9, and inserting positioning holes 33 formed in the printed wiring board 24 into the positioning pins 32.

In this case, the printed wiring board 24 is mounted with the three hole ICs 2B arranged at equal pitches facing the rotor 19 side, and the three element holding parts 34 for storing and holding each hole IC 2B are installed in the board storage part. 29 so as to protrude toward the rotor 19 side. Each element holding part 3
4, as shown in FIG.
The ribs 36 on the inner circumferential side are thin and the ribs 37 on the outer circumferential side are thick. The two thin ribs 36 on the sides support the hole IC 23 from the inside.

Therefore, the four ribs 36, 37 form a set to constitute one element holding part 34, and the tip side of each rib 36, 37 (
The insertion side) portion is formed in an inclined shape to guide the hole IC2B, and serves as guide portions 36a and 37a. The Hall IC 23 accommodated in the element holding portion 34 having such a configuration is connected to the rotor magnet 22 as shown in FIG.
The rotor magnet 22 comes into contact with the outer circumferential side wall of the circular arc-shaped four portion 35 protruding toward the inner circumferential side of the rotor magnet 22 , and comes close to the inner circumferential surface end of the rotor magnet 22 , so that leakage magnetic flux of the rotor magnet 22 is detected through the outer circumferential side wall of the circular arc-shaped recess 35 . It has become. The rotor 19 is rotated by switching the energization to the U-phase, ■-phase, and W-phase stator coils 16 based on the output signal of each Hall IC 23.

On the other hand, in order to extract the output signal of Hall IC23,
As shown in FIG. 6, a signal line 38 is soldered to the printed wiring board 24 near the center, and the signal line 38 is connected to the signal line lead-out hole 3 formed in the front frame 12 as shown in FIG. The structure for accommodating and holding the signal line 38 within the front frame 12 will be described below. That is, the signal line 3 is placed in the board storage section 29.
A signal line accommodating part 40 is integrally molded so that a portion serving as a lead-out path of 8 is recessed, and the signal line 38 is housed between this signal line accommodating part 40 and the printed wiring board 24. Furthermore,
A signal line guide part 41 is integrally molded into the mounting base 25 in the shape of a groove for guiding the signal line 38 drawn out from the signal line storage part 40 to the signal line lead-out hole 39. The signal line 38 is held between the front end surface of the front frame 12 and the signal line 38 as shown in FIG.

Next, the assembly procedure of the main parts will be explained.

First, a hole IC is installed at a predetermined position on the printed wiring board 24.
Insert and set the terminal 23, and connect the signal line 38
The core wire at the tip is also inserted and set in a predetermined position on the printed wiring board 24 (do not solder it yet in this step).

In this way, the hole IC is placed on the printed wiring board 24.
2B and the signal line 38, attach the mounting base 25 from above so as to cover the printed wiring board 24, thereby pushing the printed wiring board 24 into the board storage part 29, and inserting the hole IC 23 into the element holding part. 34 and hold it. At this time, the printed wiring board 24
In the process of pushing the board into the board storage part 29, the positioning pins 32 of the two board storage parts are inserted into the positioning holes 33 of the printed wiring board 24, and the printed wiring board 24 is positioned. Also, in the process of pushing the hole IC 23 into the element holding part 34, the inclined guide part 36a at the tip of each rib 36, 37.

37a acts to guide the hole I C2B, -1
2= This allows the element to be pushed into the element holding portion 34 smoothly. In this way, with the printed wiring board 24 set on the mounting base 25, the printed wiring board 24
The screw 31 inserted through the board storage section 29 is tightened and fixed to the screw boss 30 of the board storage section 29.

After that, after soldering the terminal of the Hall IC 23 and the core wire of the signal line 38 to the printed wiring board 24,
is placed on the signal line guide section 41, and attach the mounting base 25.
is set in a predetermined position in the front frame 12, and the screws 28 inserted into the screw insertion holes 27 of the front frame 12 are tightened to the screw bosses 26 of the mounting base 25.
is fixed to the front frame 12, the installation work of the hole IC 23 is completed, and the signal line 38 is fixed to the signal line guide part 41.
and the front end surface of the front frame 12. Note that the signal line 38 may be soldered to the printed wiring board 24 in advance before setting the Hall IC 2B.

By the way, this embodiment differs from the conventional one in that the printed wiring board 24 is fixed to the screw boss 30 of the base temporary storage part 29 of the mounting base 25 so as to be positioned on the back side when viewed from the end face side of the rotor 19. point and its mounting base 2
5 is integrally molded with an element holding portion 34 for housing and holding the hole IC2B. In this case, printed wiring board 2
4 is mounted on the mounting base 24 so as to face the end surface of the rotor 19 as in the past, the mounting base 25 and the hole IC 23 are separated by the printed wiring board 24. However, as in this embodiment, the printed wiring board 24 is attached to the mounting base 25 from the end surface side of the rotor 9. If the element holding part 34 is fixed so as to be positioned on the back side when viewed, the element holding part 34 can be integrally molded on the mounting base 25. This makes it possible to hold the Hall IC23 without preparing a separate holder for the Hall IC23, unlike in the past, without increasing the number of parts or reducing assembly efficiency.
By improving the positional accuracy of Hall IC23, rotor 19
The rotation detection accuracy can be improved.

Moreover, since the signal line storage section 40 and the signal line guide section 41 are also integrally molded on the mounting base 25, the Hall IC 2 can be mounted on one mounting base 25 without requiring a separate member.
It is also possible to hold the signal wire 38 of the rotor 11 inside the motor outer shell 1, which contributes to reducing component costs and improving assembly efficiency. The soldering of the signal line 38 can reliably prevent excessive tensile force from being applied to the part from the outside. , can improve reliability.

Further, in this embodiment, since the inclined guide parts 36a and 37a are formed at the insertion opening portion of the element holding part 34, the guiding action of the guide parts 36a and 37a allows the element holding part 34 to
This has the advantage of being able to be inserted smoothly into the layer, improving layer compatibility.

In this embodiment, each of the element holding portions 34 is composed of four ribs 36, 37, but this may be made up of three or five ribs.
It may be constructed with more than one rib, or it may be constructed with a rectangular tube instead of the ribs.

In addition, the present invention allows the shape of the mounting base 25 to be changed as appropriate, and as a magnetic detection element other than a Hall IC.
For example, various modifications are possible, such as applying it to a device using a Hall element or a magnetoresistive element.

[Effects of the Invention] As is clear from the above description, the present invention includes fixing a printed wiring board to the board supporting portion of the τI base so as to position it on the back side when viewed from the end surface side of the rotor, and Since the element holding part that houses and holds the magnetic detection element is integrally molded on the mounting base, the magnetic detection element can be held without the need for a separate holder for the magnetic detection element.
The positional accuracy of the magnetic detection element can be improved, and the rotor rotation detection accuracy can be improved without causing an increase in the number of parts or a decrease in assembly efficiency.

In this case, if the signal line storage section and signal line guide section are also integrally molded on the mounting base, the signal line of the magnetic detection element can be held within the motor outer shell using one mounting base without requiring a separate part. This also contributes to reducing parts costs and improving assembly efficiency, and also prevents the signal wire from coming loose and touching the rotor, or the soldering of the signal wire from being subjected to excessive tension from the outside. It can reliably prevent the application of force, prevent disconnection of signal lines, poor connections, etc., and improve reliability.

[Brief explanation of the drawing]

1 to 10 show an embodiment of the present invention, in which FIG. 1 is an enlarged longitudinal cross-sectional view showing the fixing structure of the printed wiring board, and FIG. 2 is an enlarged longitudinal cross-sectional view showing the holding structure of the Hall IC. 3 is a vertical cross-sectional view taken along a section of the Hall IC, FIG. 4 is a vertical cross-sectional view taken along a wiring part of a signal line of the Hall IC, and FIG. The figure is a top view of the brushless motor, Figure 6 is a top view showing the printed wiring board installed on the J base, Figure 7 is a diagram of the mounting base, and Figure 8 is a diagram of the mounting base. FIG. 9 is a vertical sectional view, FIG. 9 is a bottom view of the mounting base, FIG. 10 is an enlarged perspective view of the element holding part, and FIG. 11 is a view corresponding to FIG. 1 showing a conventional example. 11 is a motor outer shell, 12 is a front frame, 13 is a rear frame, 16 is a stator coil, 19 is a rotor, 2
2 is a rotor magnet, 23 is a Hall IC (magnetic detection element), 24 is a printed wiring board, 25 is a mounting base, 2
6 is a screw boss (base fixing part), 29 is a board storage part, 3
0 is a screw boss (board support part), 32 is a positioning pin, 3
3 is a positioning hole, 34 is an element holding part, 35 is an arcuate recessed part, 36 and 37 are ribs, 36a and 37a are guide parts,
38 is a signal line, 39 is a signal line lead-out hole, 40 is a signal line storage part, and 41 is a signal line guide part. Applicant Toshiba Corporation Agent Patent Attorney Tsuyoshi Sato

Claims (2)

[Claims] 1. A magnetic detection element for detecting the rotational position of the rotor is disposed on a printed wiring board, and this printed wiring board is disposed inside the motor outer shell via a plastic mounting base.
A brushless motor in which the magnetic detection element is located near an end face of the rotor, the brushless motor comprising: a base fixing portion integrally molded with the mounting base for fixing the mounting base to the motor outer shell; a board support part integrally molded on the base for fixing the printed wiring board so as to be positioned on the back side when viewed from the end face side of the rotor; and a board support part integrally molded on the mounting base and protruding toward the rotor side. A brushless motor comprising an element holding part that houses and holds a magnetic detection element. 2. The mounting base includes a signal line storage part that stores the signal line of the magnetic detection element between the printed wiring board and a signal line storage part that guides the signal line from this signal line storage part to the signal line lead-out hole of the motor outer shell. 2. The brushless motor according to claim 1, wherein a signal line guide portion for holding the signal line between the motor outer shell and the signal line guide portion is integrally molded.