KR200146527Y1 - Bldc motor of double rotor system having air cooling structure - Google Patents

Abstract

In order to prevent the output decrease and the thermal runaway of the output transistor caused by the fatal temperature rise generated during the operation of the BLDC motor, the double rotor has a through hole for radiating heat generated from the drive coil and the drive element inside the motor to the outside. And a double rotor type BLDC motor having an air cooling structure formed in an upper / lower case.

The motor having the air-cooled structure of the present invention has a plurality of sets of magnets of the north pole and the south pole alternately arranged in the form of a disk and the first and second rotors arranged at a predetermined interval from each other, and through the bushing in the center of the rotor Combined rotating shaft, the upper / lower case for rotatably supporting the rotating shaft, and the outer circumference is fixedly coupled between the upper / lower case and are provided with a predetermined gap between the first and second rotor, respectively, The stator coil is supported by a molding filler and is formed of an annular disk, and a control printed circuit board for applying a driving current to the stator, wherein the upper / lower case, the control printed circuit board, and the first and The second rotor is characterized by having a plurality of ventilation holes through which the outside air can be circulated into the motor.

In the present invention, the heat output of the motor can be prevented and the thermal runaway of the output transistor can be prevented by releasing heat inside the motor to the outside through the ventilation hole.

Description

Double rotor type BC motor with air cooling structure

The present invention relates to a double rotor type brushless DC (BLDC) motor having an air-cooled structure. In particular, in order to prevent the output decrease and the thermal runaway of the output transistor due to the fatal temperature rise generated during the operation of the BLDC motor, A double rotor type BLDC motor having an air cooling structure in which a through hole for radiating heat generated from a coil and a driving element to the outside is formed in a double rotor and an upper / lower case.

BLDC motors are generally divided into core type (or radial type) and coreless type (or axial type) having a cup (cylindrical) structure according to whether or not they have a stator core.

The core type BLDC motor has an inner magnet type composed of a cylindrical stator coiled with a coil and a rotor made of a cylindrical permanent magnet in order to have an electromagnet structure on a plurality of protrusions formed on the inner circumference, or a plurality of protrusions formed on the outer circumference of the stator. The coil is wound in the up / down direction, and is classified into an external magnet type in which a rotor is formed of a cylindrical permanent magnet magnetized on the outside thereof.

Since the core type BLDC motor has a structure in which the magnetic circuit is symmetrical in the radial direction about the axis, it has the advantages of low vibration noise, suitable for low speed rotation, and good torque, whereas yoke during stator fabrication It has the disadvantage of high material loss and high capital investment in mass production. In addition, the structure of the stator and the rotor is complicated, the thinning is disadvantageous, there is a difficulty in improving the efficiency and cogging (cogging) torque occurs.

On the other hand, in the conventional coreless BLDC motor proposed to improve the disadvantages of the core type BLDC motor, a rotor consisting of an annular magnet and a yoke is fixedly coupled to a rotating shaft, and a plurality of stator coils are provided on a printed circuit board (PCB). It has a structure in which a rotating shaft is coupled to a stator formed by winding through a bearing.

The coreless BLDC motor is a magnet in up / down direction having the same direction as the axial direction between a rotor composed of a plurality of magnets integrally and a stator composed of a stator coil generating a plurality of sets of electromagnetic forces disposed thereunder. Since the circuit is formed, vibrations in the axial direction are structurally large even when a buffer spring is inserted between the bearings due to the suction or reaction force of the stator and the uneven magnetization of the stator.

In addition, this axial vibration causes resonance of the entire system during the motor-driven rotational drive, thereby increasing the rotational noise. Accordingly, the efficiency of the entire motor at high speed is good without loss, while vibration noise is synthesized with the rotational noise to cause abnormal sound.

As a result, the material loss can be minimized, mass production is good, and the thickness and size can be reduced compared to the core type BLDC motor, resulting in low cost and high efficiency, but it has a fatal flaw that the noise is generated by axial vibration during rotation. .

Accordingly, the present application provides a double rotor / stator method that can increase the torque by more than two times while canceling the axial vibrations generated when the rotor is rotated through Patent Application Nos. 96-976 and 977 of January 18, 1996. A coreless BLDC motor has been proposed.

For example, the coreless BLDC motor proposed in the above-mentioned patent application No. 96-977 has a disc-shaped first and second rotors in which a plurality of sets of magnets of N and S poles are alternately arranged, A rotating shaft coupled to the center through a bushing, a left / right case rotatably supporting the rotating shaft, and installed with a predetermined gap between the first and second rotors, respectively, are disposed in the first and second rotors. It consists of first and second stators with a plurality of bobbinless stator coils for applying electromagnetic forces in opposite directions.

In the foregoing application, a plurality of wound stator coils each having a double stator structure mounted on the left and right sides of the PCB in the middle of the first and second double rotors are formed in a magnetic circuit having a symmetrical structure with respect to the stator and the rotor rotation axis as a whole.

In this case, in the stator coils of the corresponding first and second stators, the winding direction of the coil and the current flow direction are set so as to suck the corresponding magnets of the first and second rotary rotors from each other or repel each other. Therefore, the first and second rotors are subjected to the same magnitude of suction or repulsion force in opposite directions by the first and second stators, so that the suction or repulsive forces acting on the first and second rotors by each stator cancel each other. The axial vibration of the rotor is minimized.

On the other hand, the applicant of the patent application No. 96-18767 to improve the durability and the production cost can be reduced by constructing the stator of the symmetrical double rotor / stator type coreless BLDC motor in a single body by insert molding Proposed in issue (1996.5.30).

In the BLDC motor, as shown in FIG. 1, the outer circumferential portion 67 of the stator 51 extends up and down in the middle of the upper / lower cases 71A and 71B, and is coupled between them to form a cylindrical case. Form.

The upper rotor 73A and the lower rotor 73B having a magnet-divided multipole arrangement structure with a predetermined air gap on the upper and lower portions of the stator 51 are rotated through the central bushings 75A and 75B. Fixedly coupled to

Each of the rotors 73A and 73B has eight magnets 81A and 81B, that is, four disk-type N-pole magnets and four disk-type S-pole magnets alternately made of nonmagnetic material, for example PET, nylon 66 or PBT. The circumferential portion is supported on the support body 79 formed integrally with the bushings 75A and 75B, and the annular magnet yokes 83A and 83B are integrally attached to the rear surface to form a magnetic circuit for eight magnets 81. Structure.

On the other hand, an auxiliary magnet 85 for detecting a Hall element position is attached to the upper side of the magnet yoke 83A of the upper rotor 73A, and the auxiliary magnet 85 is fixed to the inner circumference of the upper case 71A. It is arrange | positioned facing the hall element 89 of (87). In addition, one side of the control PCB 87 is provided with a female connector 91 to which the upper terminal 63A of the stator 51 is press-fitted.

Upper and lower bearings 93A and 93B are fixedly installed at the centers of the upper case 71A and the sewer case 71B, and the rotary shafts 77 of the rotors 73A and 73B are provided through the bearings 93A and 93B. This is rotatably supported.

In FIG. 1, reference numeral 95 denotes a bushing for keeping the gap, and 97 denotes a fixing screw (bolt) for fixing the upper / lower cases 71A and 71B.

On the other hand, the stator 51 has a coil 55 wound around the plastic square bobbin 53 in a square shape, and the six square bobbin coils 55 are connected to each other by insert molding. Together with the auxiliary printed circuit board (PCB) 57 for forming, it is molded in the form of a disc by a resin insulating material.

Here, a through hole 61 is formed at the center of the auxiliary PCB 57 and the stator stator body 59, and an upper terminal 63A for electrical connection with the control PCB 87 at one side of the stator body 59. When adopting a multi-stage stacking structure, a lower terminal is formed embedded for mutual electrical connection with the stator of another stage.

The bobbin coil 55 may be wound in a general short and multi-axis winding machine using a plastic square bobbin 53 without using a separate dedicated winding machine and is easy to automate. However, ordinary insulated copper wire, which is 25 to 50% cheaper than this, can be used.

In the above structure, the stator 51 is composed of a single body, and the coil 55 can be wound / assembled using the bobbin 53 to realize high productivity and low manufacturing cost, and reliable insulation between the coils 55 is provided. It is made, moisture resistance, vibration absorption and corrosion resistance is also excellent and the durability of the overall motor can be improved by increasing the support strength of the motor.

Further, when the stator is integrally molded by an insert molding method using a bobbinless coil instead of the bobbin coil, the output of the motor can be further increased.

However, in the conventional double rotor / stator type coreless BLDC motor, the upper and lower cases and the outer circumference of the stator have a cylindrical shape as a whole and form a closed space. Therefore, when the motor is driven for a long time, heat is generated from the output transistor installed in the control PCB, the stator coil constituting the stator and the integrated circuit.

In this case, in the hermetic structure, for example, the surface temperature of the coil and the transistor module exceeds 100 ° C. after 1 hour after the power is turned on, causing a problem of output depletion due to thermal runaway of the output transistor and rise in temperature.

Therefore, the present invention has been devised in view of the problems of the prior art, and its purpose is to prevent output deceleration and output transistor thermal runaway due to the fatal temperature rise that occurs during BLDC motor driving. The present invention provides a double rotor type BLDC motor having a double rotor and an air cooling structure formed in an upper / lower case to heat dissipated heat to the outside.

1 is an axial sectional view showing the structure of a double rotor type BLDC motor.

2 is an axial sectional view of a double rotor type BLDC motor having an air cooling structure according to the present invention.

3 is a schematic plan view showing a relationship between a magnet according to the present invention and a magnet yoke in which magnetic leakage holes are formed.

4 is a graph showing the temperature of the capacitor and the transistor according to the driving time in the case of the air-cooled structure motor according to the present invention.

5 shows the temperature of the capacitor and the transistor according to the driving time in the case of the conventional hermetic structure motor.

* Explanation of symbols for main parts of the drawings

11, 13, 15, 17A, 17B, 21A, 21B: Ventilation hole 19: Magnetic leakage hole

51: stator 55: coil

57: auxiliary PCB 59: stator body

61: through hole 63: connecting terminal

65 through hole 67 stator outer periphery

71A / 71B: Upper / Lower Case 73A / 73B: Upper / Lower Rotor

75A / 75B: Bushing 77: Shaft

79: support 81A / 81B: magnet

83A / 83B: Magnet York 87: Control PCB

89: hall element 91: connection terminal

93A / 93B: Upper / Lower Bearing 97: Retaining Screw

In order to achieve the above object, the present invention is the first and second rotors arranged in a predetermined interval from each other in the form of a disk in which a plurality of sets of magnets of the north pole and the south pole are alternately arranged, and the bushing in the center of the rotor. A rotary shaft coupled through the upper / lower case rotatably supporting the rotary shaft, and an outer circumferential portion fixedly coupled between the upper / lower cases and having a predetermined gap between the first and second rotors, respectively. In order to apply electromagnetic forces in opposite directions to the first and second rotors, a plurality of stator coils are supported by a molding filler to form a stator formed in an annular disk shape, and installed inside either one of the upper and lower cases, and It is composed of a control printed circuit board for applying a drive current, the outside air to the upper and lower cases, the control printed circuit board, and the first and second rotors It provides a double rotor type BCD motor having an air-cooled structure, characterized in that it has a plurality of ventilation holes that can be circulated into the motor.

The plurality of ventilation holes are located at opposite positions of the upper / lower case, the control printed circuit board, and the first and second rotors. do.

Furthermore, it is preferable to further provide a plurality of ventilation holes between the upper and lower cases and the outer circumferential portion of the stator.

In the present invention, a magnetic leakage hole through which magnetic flux can leak from the magnet of the rotor is formed in the magnet yoke of the rotor, and a Hall element is disposed on the rear surface of the control printed circuit board facing the rotor.

As described above, the present invention maintains the temperature inside the motor by keeping the temperature inside the motor low by forming the through-coil in the upper rotor and the lower case by forming a through hole for dissipating heat generated from the drive coil and the drive element to the outside. The reduction and thermal runaway of the output transistors can be prevented.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is an axial cross-sectional view of a double rotor type BLDC motor having an air cooling structure according to the present invention, which is a bobbinless type, and FIG. 3 shows a relationship between a magnet according to the present invention and a magnet yoke in which magnetic leakage holes are formed. Figure 4 is a schematic plan view, Figure 4 is a graph showing the temperature of the capacitor and the transistor according to the drive time in the case of the air-cooled structure motor according to the present invention, Figure 5 is a capacitor and transistor according to the drive time in the case of a conventional hermetic structure motor A graph showing the temperature of.

First, as shown in FIG. 2, a double rotor type BLDC motor having an air cooling structure by self cooling according to the present invention is basically configured to have the same operation principle as a device similar to the motor pre- filed by the present applicant. do.

Therefore, for example, the same reference numerals are assigned to the same elements as those shown in FIG. 1 and detailed description thereof will be omitted.

Referring to FIG. 2, reference numeral 51 is a stator, 55 is a coil, 57 is an auxiliary PCB, 59 is a stator body, 61 is a through hole, 63 is a connecting terminal, 65 is a through hole, 67 is a stator outer circumference, and 71A is an upper part. Case 71B is lower case, 73A is upper rotor, 73B is lower rotor, 75A, 75B is bushing, 77 is rotating shaft, 79 is support, 81A, 81b is magnet, 83A, 83B is magnet yoke, 87 is control PCB, 89 is Hall element, 91 is a connection terminal, 93A93B is an upper / lower bearing, 97 is a fixing screw.

In the present invention, the changed point is a position opposite to each other of the upper / lower case 71A, 71B and the control PCB 87, preferably a plurality of ventilation holes 11, 13, 15 at positions adjacent to the rotation axis 77. ) And a plurality of ventilation holes in the magnet yoke 83A, 83B of the upper / lower rotors 73A, 73B and the support 79 at positions corresponding to the through holes 11, 13, 15, respectively. (17A, 17b) were formed through.

In this case, in the present invention, instead of the auxiliary magnet for detecting the position of the Hall element for the arrangement of the ventilation holes 17A and 17B, the installation of the Hall element 89 has been moved and the magnet (83A) is opposed to the magnet yoke 83A. Magnetic leakage holes 19 from 81A were formed so that the hall element 89 could detect the leakage magnetic flux.

The ventilation holes 11, 13, 15, 17A, and 17B are formed at about 4-6 at equal intervals on the circumference. In addition, the ventilation holes 17A and 17B are inclined inwards or rotated in the rotational direction, respectively, and have high heat dissipation efficiency.

In addition, the stator outer periphery 67 also discharges the air introduced into the motor from the outside through the ventilation holes 11, 13, 15, 17A, and 17B at predetermined intervals at upper and lower portions along the circumference, respectively. A plurality of ventilation holes 21A and 21B are formed.

The air cooling action of the BLDC motor having the air cooling structure by the self cooling as described above will be described in detail below.

When a motor control signal is applied to the control PCB 87 from the outside, the stator driving signal is transmitted from the control integrated circuit and the output transistor 23 through the connection terminals 91 and 63A and the auxiliary PCB 57. Is applied to.

Accordingly, the upper and lower rotors 73A and 73B rotate. In this case, the outside air introduced into the ventilation hole 11 of the upper case 71A passes through the ventilation hole 15 of the control PCB 87 and the ventilation hole 17A of the upper rotor 73A. It is discharged to the outside through the ventilation hole 21A via the gap between the magnet and 81A.

On the other hand, the external air introduced from the ventilation hole 13 of the lower case 71B as the rotors 73A and 73B rotates passes through the ventilation hole 17B of the lower rotor 73B, and the coil 55 and the magnet ( It is discharged to the outside through the ventilation hole 21b formed in the stator outer peripheral part 67 via the gap between 81B.

Furthermore, according to the present invention, the leakage magnetic flux of the magnet 81A is transferred to the Hall element 89 through the long hole-shaped magnetic leakage hole 19 without separately installing an auxiliary magnet required for detecting the rotation positions of the rotors 73A and 73B. It can detect by this, and can reduce cost.

In this case, the distribution difference of the magnetic field formed largely depends on the inner diameter D1 of the magnet yoke 83A, and the appropriate inner diameter D1 is {PCD (D-2) -magnet inner diameter (D3) of the magnet}- It is preferable to obtain by 2.

As a result of forming the air-cooled structure as described above, in the present invention, when the motor is driven at the voltage (V), current (mA), and rotation speed (rpm) shown in Table 1, the temperature of the coil, capacitor, and transistor (T1-). T3) is shown in Table 1, and as shown in the graph of FIG. 3, the temperature (T2, T3) of the capacitor and transistor is shown in the coil temperature (T1) up to 61.8 ° C and the temperature of the capacitor ( T2) was maintained at a maximum of 67.9 ° C and the transistor temperature (T3) was maintained at a maximum of 66.9 ° C.

In contrast, in a conventional motor having a sealed structure, the temperature (T1A-T3A) of the coils, capacitors, and transistors when the motor is driven at the voltage (V), current (mA), and rotation speed (rpm) shown in Table 2 is shown in the table. The temperature (T2A, T3A) of the capacitors and transistors is shown in FIG. 2 and shown in FIG. As shown, the transistor temperature (T3A) exceeds 100 ° C for 30min continuous operation, the coil temperature (T1A) is up to 78.5 ° C, the capacitor temperature (T2A) is up to 123.0 ° C, and the transistor temperature (T3A). ) Recorded a maximum of 145.0 ° C and then the temperature dropped rapidly.

As described above, in the present invention, the temperature T3 of the transistor is maintained at about 67 ° C. even for five hours of continuous driving. However, in the conventional motor, the transistor is damaged after 36 minutes.

As described above, the present invention maintains the temperature inside the motor by keeping the temperature inside the motor low by forming the through-coil in the upper rotor and the lower case by forming a through hole for dissipating heat generated from the drive coil and the drive element to the outside. The reduction and thermal runaway of the output transistors can be prevented.

In the above, the present invention has been illustrated and described by way of specific preferred embodiments, but the present invention is not limited to the above-described embodiments and the general knowledge in the art to which the present invention belongs without departing from the spirit of the present invention. Various changes and modifications can be made by those who have

Claims (4)

(1) a first and second rotors arranged at predetermined intervals in the form of disks in which a plurality of sets of magnets of the north pole and the south pole are alternately arranged, and (2) a rotating shaft coupled to the center of the rotor through a bushing; (3) an upper / lower case rotatably supporting the rotating shaft, and (4) an outer circumferential portion is fixedly coupled between the upper / lower case and provided with a predetermined gap between the first and second rotors, respectively. In order to apply electromagnetic forces in opposite directions to the first and second rotors, a plurality of stator coils are supported by a molding filler and formed in the form of an annular disk, and (5) installed inside any one of the upper and lower cases. And a control printed circuit board for applying a driving current to the stator, wherein external air may be circulated into the motor in the upper / lower case, the control printed circuit board, and the first and second rotors. A double rotor type BCD motor having an air cooling structure, characterized by having a plurality of ventilation holes. 2. The plurality of ventilation holes of claim 1, wherein the plurality of ventilation holes are located at opposite positions of the upper / lower case, the control printed circuit board, and the first and second rotors. Double rotor type DC motor having an air-cooled structure characterized in that formed through. The BCD motor of claim 1 or 2, further comprising a plurality of ventilation holes between the upper / lower case and the outer periphery of the stator. 2. The air cooling according to claim 1, wherein a plurality of magnetic leakage holes for leaking magnetic flux from the magnet of the rotor are formed in the magnet yoke of the rotor, and the Hall element is disposed on the rear surface of the control printed circuit board facing the rotor. BCD motor with double rotor type structure.