JPH0567185U - Brushless DC motor - Google Patents

Abstract

(57) [Abstract] [Purpose] To facilitate the attachment of the magnetic sensor of the brushless DC motor. [Structure] Sensor mounting holes 10c and 10d are provided by penetrating a printed circuit board 10. Magnetic sensor 21 for detecting the position of rotor 6 and magnetic sensor 2 for detecting speed
The terminals 21b and 22b of No. 2 are bent on the same side. The sensor bodies 21a and 22a are inserted into the mounting holes 10c and 10d from the back surface side of the printed circuit board together with the bent terminals 21b and 22b, and the terminals are soldered to the circuit pattern 10e provided on the back surface of the printed circuit board 10.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brushless DC electric motor.

[0002]

[Prior Art]

 As shown in FIG. 6, the brushless DC motor includes a frame 1 having a boss portion 1a and a flange portion 1b, and a rotating shaft 3 supported by bearings 2 and 2 arranged inside the boss portion of the frame. And a rotor 6 composed of a permanent magnet 5 which is fixed to the inner circumference of the peripheral wall of a cup-shaped rotor yoke 4 attached to the rotary shaft 3 and is magnetized in the radial direction of the rotor. A stator 9 in which an armature coil 8 is wound around a child iron core 7, a printed circuit board 10 arranged in a state of being orthogonal to a central axis of the rotor, and a rotor by detecting magnetic flux generated from the permanent magnets 5. , A ring-shaped permanent magnet 12 fitted on the outer circumference of the rotor yoke 4, and a magnetic sensor 13 for detecting the magnetic flux generated from the permanent magnet 12 to detect the rotational speed of the rotor. It consists of The printed board 10 is arranged with its surface 10a facing the opening end of the rotor yoke and fixed to the stator 9, and the magnetic sensors 11 and 13 are attached to this printed board. There is. Although not shown, the printed circuit board 10 is further provided with components of a control circuit such as a power transistor for controlling on / off of energization of the armature coil 8.

In a conventional electric motor of this type, the magnetic sensors 11 and 13 are composed of Hall elements (Hall ICs, MR elements, etc.) and magnetic saturation elements, and these sensors generate magnetic flux from the permanent magnets 5 and 12. The respective bodies are arranged so as to face the permanent magnets 5 and 12 for detection. Then, the lead terminals led out from the main body of each magnetic sensor are inserted from the front surface side of the printed circuit board 10 into the terminal insertion holes provided in the printed circuit board 10, and the back surface of the printed circuit board 10 (the surface on the flange portion 1b side). It was soldered to the circuit pattern provided on the.

In the brushless DC motor, the magnetic sensor 11 for detecting the position of the rotor is indispensable for controlling the energization of the armature coil, but the magnetic sensor 13 for detecting the rotation speed is omitted. There is also.

[0005]

[Problems to be solved by the device]

 In a conventional brushless DC motor in which the position and rotation speed of the rotor are detected by a magnetic sensor, the lead terminals led out from the main body of the magnetic sensor are connected to the terminal insertion holes provided on the printed board on the front side Since the magnetic sensor is mounted by inserting it from the beginning, when mounting the magnetic sensor on the printed circuit board, a laborious work of inserting the lead terminal into the small hole of the printed circuit board is required, which causes a problem of poor work efficiency.

An object of the present invention is to provide a brushless DC electric motor in which a magnetic sensor can be easily attached.

[0007]

[Means for Solving the Problems]

 The present invention is provided on the rotor side, in which the printed circuit board is arranged with the surface facing the opening end of the rotor yoke formed in a cup shape, and the printed circuit board is supported with respect to the stator. The present invention relates to a brushless DC motor in which a magnetic sensor for detecting magnetic flux generated by a magnet is attached to a printed circuit board.

In the present invention, the sensor mounting hole is provided by penetrating the printed circuit board, and the sensor is inserted into the sensor mounting hole from the back side of the printed circuit board, and the sensor is provided with an axial line on the magnet provided on the rotor side. Face each other. The terminals derived from the body of the magnetic sensor are connected to the circuit pattern provided on the back side of the printed circuit board.

[0009]

[Action]

 As described above, when the magnetic sensor is mounted by inserting it into the sensor mounting hole provided in the printed circuit board, the sensor can be positioned automatically, so that the sensor can be mounted easily. If the sensor body is inserted into the sensor mounting hole from the back side of the printed circuit board as described above, the terminals derived from the sensor body can be directly soldered to the circuit pattern on the back side of the board. Since the troublesome work of inserting the terminals into the terminal insertion holes of the board can be omitted, the work efficiency of the mounting work of the sensor can be improved.

Further, when the sensor main body is inserted and mounted in the sensor mounting hole provided on the printed circuit board as described above, the permanent magnet faces the magnetic sensor in the axial direction. It is not necessary to provide a portion facing the magnetic sensor on the inner or outer peripheral surface of the magnet. Therefore, the axial length of the permanent magnet can be shortened, and the axial dimension of the electric motor can be reduced.

[0011]

【Example】

 1 and 2 show an embodiment of the present invention, in which the same parts as those of the conventional electric motor shown in FIG. 6 are designated by the same reference numerals. The ring-shaped permanent magnet 12 fitted to the outer periphery of the rotor yoke 4 in order to obtain a signal for detecting the rotation speed has a large number of speed detection magnetic poles arranged in the circumferential direction on the end face 12a facing the printed circuit board 10. , The respective magnetized regions are magnetized in the axial direction. Sensor mounting holes 10c and 10d are provided by penetrating through the printed circuit board 10 at positions corresponding to the permanent magnets 5 and 12, respectively, and the magnetic sensors 21 and 20d for detecting the rotor position are respectively provided in these mounting holes 10c and 10d. A magnetic sensor 22 for speed detection is inserted. Each of the magnetic sensors 21 and 22 comprises a magnetic detection element such as a Hall IC, an MR element, a magnetic saturation element or the like, and has a structure in which terminals 21b and 22b are led out in the axial direction from both ends of the sensor bodies 21a and 22a, respectively. is doing.

In the present embodiment, as shown in FIG. 3, the terminals 21b (the number of terminals is arbitrary) led out from both ends of the sensor body 21a are bent to the same side near their roots. An arm portion 21b1 extending in a direction inclined with respect to the axial direction of the sensor body 21a, and a soldering portion 21b2 bent from a tip portion of the arm portion 21b1 in a direction parallel to the axial direction of the sensor body 21b1. It is shaped into a shape. The sensor main body 21a is inserted into the mounting hole 10c from the back surface 10b side of the printed circuit board 10 together with the terminals 21b led out from both ends thereof, and the soldering portion 21b2 at the tip of the terminal 21b is provided on the back surface of the printed circuit board 10. It is brought into contact with the pattern 10e and soldered to the circuit pattern.

In the present embodiment, in the state before the sensor body 21a is inserted into the mounting hole, the maximum value L of the distance between the arm portions 21b1 of the terminals led out from both ends of the sensor body 21a and bent is When the sensor body 21a is inserted into the mounting hole, the bent terminal 21b is deformed and the arm portion 21b1 of the terminal is elastically attached to the inner surface of the mounting hole. Keep in contact. According to this structure, the elasticity of the bent terminal allows the sensor to be held in the mounting hole until the soldering of the terminal is completed, which facilitates the assembly.

The mounting method of the magnetic sensor 22 is exactly the same as the mounting method of the magnetic sensor 21. The magnetic sensor 22 is mounted in the mounting hole 10d and faces the end surface (magnetic pole surface) of the ring-shaped permanent magnet 12. To be made.

FIG. 4 shows a main part of another embodiment of the present invention. In this embodiment, an adhesive 23 is applied to the opening end portion of the mounting hole 10c provided on the printed board on the back surface side of the board. In this state, the main body 21a of the magnetic sensor together with the bent terminal 21b is inserted into the mounting hole 10c from the back surface side of the board.

When the sensor body 21a is inserted into the mounting hole 10c, the adhesive 23 flows into the mounting hole 23 together with the sensor body, and the adhesive 23 fixes the sensor body 21a in the mounting hole. The soldering portion 21b2 at the tip of the terminal 21b is brought into contact with a circuit pattern (not shown in FIG. 4) provided on the back surface of the printed circuit board 10 to be soldered. In this case, in order to prevent the soldering of the terminal 21b from being defective by the adhesive 23, the adhesive 23 needs to be applied only to the portion corresponding to the end portion of the sensor body where the terminal 21b is not provided.

Also in the embodiment shown in FIG. 4, when the terminal 21b of the magnetic sensor is elastically contacted with the inner surface of the mounting hole 10c, the sensor body is kept in the mounting hole until the adhesive 23 is cured. Since it can be held, manufacturing can be facilitated. However, in the embodiment of FIG. 4, the sensor body is fixed in the mounting hole with an adhesive, so it is not always necessary to elastically contact the terminal 21b with the inner surface of the mounting hole, and an appropriate jig should be used. The sensor body may be held in the mounting hole by. In particular, if an immediate-dry adhesive is used as the adhesive 23, the assembling workability will not be impaired without elastically contacting the terminal 21b with the inner surface of the mounting hole.

FIG. 5 shows still another embodiment of the present invention. In this embodiment, the terminal 21b is led out from a portion of the main body 21a of the magnetic sensor 21 near the end and the terminal 21b is bent. Without contacting the circuit pattern 10e on the back surface of the preton substrate 10 and soldering. Also in this embodiment, the sensor body 21a is fixed in the mounting hole 10c with an adhesive.

Although only the mounting structure of the magnetic sensor 21 is shown in FIGS. 4 and 5, it goes without saying that a similar mounting structure can be adopted for the magnetic sensor 22.

When a structure is adopted in which a mounting hole is provided in the printed circuit board and the sensor body is inserted into the mounting hole, only the sensor body is inserted into the mounting hole from the front surface side of the substrate, It is conceivable that each lead-out terminal may be bent into an L-shape and may be soldered to a circuit pattern on the back side of the board through a through hole provided in the board. However, in the case of such a configuration, it is inevitable that the assembly is troublesome because the laborious work of inserting the thin terminal into the small through hole of the printed circuit board is required. According to the embodiments shown in FIGS. 1 to 3, 4 and 5, the sensor can be mounted on the printed circuit board without causing the above problems.

In the embodiments shown in FIGS. 4 and 5, the sensor body is fixed in the mounting hole of the printed circuit board with an adhesive, but the sensor body and the mounting hole are tightly fitted to each other. Set the inner dimension of the mounting hole in the sensor, and hold the sensor body in the mounting hole in frictional contact with the inner surface of the mounting hole until the terminals of the sensor are soldered to the circuit pattern of the printed board. It may be allowed to.

[0022]

[Effect of the device]

 As described above, according to the present invention, since the magnetic sensor can be automatically positioned by inserting the magnetic sensor into the sensor mounting hole provided on the printed circuit board, mounting the sensor Can be facilitated. Also, the sensor body is inserted into the sensor mounting hole from the back side of the printed circuit board, so the terminals led out from the sensor body can be directly soldered to the circuit pattern on the back side of the board. The troublesome work of inserting the board into the terminal insertion hole of the board can be omitted. Therefore, there is an advantage that the work of attaching the magnetic sensor can be simplified and the work efficiency can be improved, and the mass productivity of the electric motor can be improved.

[Brief description of drawings]

FIG. 1 is a half longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an enlarged part Z of FIG.

FIG. 3 is a sectional view showing a sensor mounting structure according to another embodiment of the present invention.

FIG. 4A is an explanatory view illustrating a sensor mounting structure according to still another embodiment of the present invention. FIG. 6B is a sectional view showing a state in which the sensor is mounted in the mounting hole in the embodiment.

FIG. 5 is a sectional view showing a sensor mounting structure according to still another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a conventional brushless DC motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Frame, 3 ... Rotation axis, 4 ... Rotor yoke, 5 ... Permanent magnet, 6 ... Rotor, 7 ... Stator core, 8 ... Armature coil, 9 ... Stator, 10 ... Printed circuit boards 21, 22 ... Magnetic sensor, 21a, 22a ... Sensor body, 21b, 22
b ... Terminal.

Claims (1)

[Scope of utility model registration request] 1. A printed circuit board is arranged with its surface facing the opening end of a rotor yoke formed in a cup shape, and the printed circuit board is supported with respect to a stator and provided on the rotor side. In a brushless DC electric motor, wherein a magnetic sensor for detecting a magnetic flux generated from a magnet is attached to the printed circuit board, a sensor mounting hole is provided by penetrating the printed circuit board, and the sensor has a main body from the back side of the printed circuit board. The magnet provided on the rotor side is opposed to the magnet provided in the sensor mounting hole from the axial direction, and the terminal derived from the main body of the magnetic sensor has a circuit pattern provided on the back surface side of the printed circuit board. Brushless DC motor characterized by being connected.