KR100660305B1 - Brushless d.c motor - Google Patents

Abstract

A brushless DC motor is provided to reduce electrical noise by maintaining a constant rotation speed of the DC motor by enhancing sensing accuracy of a hall sensor. A brushless DC motor includes a front cover(20), a rotor shaft(30), a magnet(40), a stator(50), a rear cap(60), and a PCB(70). A support unit is formed on an inner surface of the front cover. The rotor shaft is rotatably installed inside the front cover. The magnet is coupled with an outer surface of the rotor shaft. The stator is arranged outside the magnet and supported by the support unit to form a cooling space inside the front cover. The stator is arranged to be apart from a front end of the front cover. The rear cap is coupled with a rear portion of the front cover. The PCB(Printed Circuit Board) is coupled with the rear cap and includes a hall sensor.

Description

Brushless DC Motors {BRUSHLESS D.C MOTOR}

1 is a perspective view of a brushless DC motor according to the present invention;

2 is an exploded perspective view showing the structure of a brushless DC motor according to the present invention;

3 is a longitudinal sectional view showing a coupling structure of a brushless DC motor according to the present invention;

4 is a cross-sectional view showing a coupling structure of a brushless DC motor according to the present invention;

5 is a perspective view illustrating a rotor shaft and a magnet coupling structure of a brushless DC motor according to the present invention.

              <Description of Symbols for Main Parts of Drawings>

             20: front cover 22: support jaw

             24: cooling space 26: cable outlet hole

             30: rotor shaft 32: shaft portion

             34: rotor portion 35: magnet coupling groove

             40: magnet 50: stator

             52: slot 60: rear cap

             62: substrate support 70: printed circuit board

             71: through hole 72: Hall element sensor

             80a, 80b: Bearing

The present invention relates to a brushless DC motor, and more particularly to a brushless DC motor capable of generating a rotational force by the interaction of the rotor and the stator.

In general, the driving device is used in a variety of industries for producing home appliances, industrial equipment, and the like, and a typical example of such a driving device is an electric motor.

Electric motors are classified into various types according to their purpose. In particular, the brushless DC motor has an advantage that the mechanical contact such as the commutator and the brush is removed, so that electrical and mechanical noise is not generated and the service life is relatively long.

The brushless DC motor is also used as a driving source of blow motors used in vehicle air conditioners.

The brushless DC motor used in the conventional blow motor includes a housing; A shaft rotatably installed in the housing; A rotor fixed to the shaft and having a plurality of magnets attached to an inner circumference thereof; A stator having a coil wound around the magnet to generate a magnetic field; It is provided inside the housing and comprises a printed circuit board (PCB) having a Hall element sensor.

However, the brushless DC motor of the above-described structure is not only relatively complicated in structure but also not compact in appearance, and thus there is a limit in applying it to a precision small device.

In addition, due to the structural characteristics of the brushless DC motor, heat generated inside the housing cannot be efficiently released. In order to solve the heat dissipation (cooling) problem, a brushless DC motor having a separate heat dissipation means such as a heat sink has been introduced, but this not only degrades the assembly and installation of the brushless DC motor, but also economic costs such as component cost. This has the disadvantage that it takes additionally.

In addition, since the Hall element sensor is positioned adjacent to the stator and interferes with the electromagnetic force of the coil, the reliability of the sensing accuracy of the Hall element sensor is relatively lowered and electrical noise is generated by lowering the constant speed of the brushless DC motor. There is a problem.

On the other hand, in recent years, the automobile industry is leading the development of technology for power supply system of 42V high voltage system according to various demands of consumers for stability, convenience, ride comfort, and low-pollution environment.

Therefore, when the vehicle power system becomes a 42V high voltage system in the future, the installation of various cutting-edge electric parts and motorized modules for the improvement of safety and performance of the vehicle will be accelerated.

One of the motorized modules that are expected to be developed / installed for improving vehicle performance in such a 42V high voltage system is a blower motor essential for an air conditioning system.

However, in Korea, technology development and patents related to electric motors as core driving parts according to the automotive 42V system system have been hardly performed, and technology development and standardization activities for active 42V high voltage system are actively promoted in major overseas automobile industries. . In particular, in the case of electric motors, research and development using brush-type motors have been made, as well as research on brushless-type motors.

The present invention was created to solve the above problems, and an object of the present invention is to provide a brushless DC motor which can improve the compactness and improve the cooling efficiency and the reliability of the hall sensor.

The present invention in order to achieve the above object, the front cover is formed with a support jaw on the inner surface; A rotor shaft rotatably installed in the front cover; A magnet coupled to the outside of the rotor shaft; A stator provided on an outer side of the magnet and supported on the support jaw so as to form a cooling space in the front cover and spaced apart from the front end of the front cover; A rear cap coupled to the rear of the front cover; It is coupled to the rear cap, characterized in that it comprises a printed circuit board is provided with at least one Hall element sensor.

The front cover and the rear cap is preferably made of a thermally conductive material.

It is preferable that the cable withdrawing hole is formed at the side of the front cover so that the cable inside can be drawn out.

The rotor shaft has one end is exposed to the outside through the front cover, the other end is a shaft portion supported by the rear cap; It is preferable to include a rotor unit which is formed integrally with the shaft portion and has a magnet coupling groove formed thereon on the outer circumferential surface thereof.

The rear cap is fitted to the rear of the front cover, it is preferable that a cylindrical substrate support portion protruding from the shaft portion is inserted into the inner central portion.

The printed circuit board is preferably detachably coupled to the substrate support.

It is preferable to further include a bearing coupled to both ends of the rotor shaft.

In addition, the brushless DC motor according to the present invention includes a front cover of a thermally conductive material having a supporting jaw formed on an inner surface thereof; A rear cap fitted to the rear of the front cover and having an inner central portion protruding from a cylindrical substrate support; It is installed inside the front cover, one end is exposed to the outside through the front cover and the other end is integrally formed with the shaft portion supported by the substrate support and the shaft portion and the magnet coupling groove is formed on the outer peripheral surface A rotor shaft having a rotor portion; A magnet coupled to the magnet coupling groove; A stator provided on an outer side of the magnet and supported on the support jaw so as to form a cooling space in the front cover and spaced apart from the front end of the front cover; A printed circuit board coupled to the substrate support portion, the center portion having a through hole through which the shaft portion passes, and having a Hall element sensor proximate to the through hole; It is characterized by including a bearing coupled to the shaft portion.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in Figures 1 to 4, the brushless DC motor (BLDC Motor) according to the present invention includes a front cover 20; A rotor shaft 30 rotatably installed inside the front cover 20; A plurality of magnets 40 coupled to the outside of the rotor shaft 30; A stator 50 provided outside the magnet 40; A rear cap 60 coupled to the rear of the front cover 20; It is configured to include a printed circuit board 70 coupled to the rear cap 60.

The front cover 20 has a cylindrical structure in which an area in front of the front is stepped and the rear is open. The front cover 20 has a support jaw 22 formed in the central area of the inner surface thereof, and a shaft through hole 28 is formed so that the rotor shaft 30 can be exposed to the outside.

Supporting jaw 22 of the front cover 20 is to facilitate the coupling of the stator 50 and to hold the concentricity (Concentricity) when the stator 50 is coupled.

On the other hand, concentricity refers to the magnitude of the error between the axis of the cylindrical portion and the reference axis in the cylindrical portion that should have the axis on the same straight line as the reference axis.

The front cover 20 is not only excellent in durability, but also preferably made of a material having excellent thermal conductivity so as to efficiently discharge heat generated therein to the outside. The front cover 20 may selectively apply various kinds of known materials having excellent physical properties such as durability and heat dissipation such as metal.

The side of the front cover 20 is formed with a cable lead-out hole 26 of a predetermined size so that the inner cable (not shown) can be easily drawn out. The size and position of the cable lead-out hole 26 can be changed as appropriate.

The rotor shaft 30 is installed inside the front cover 20 so as to be rotatable with respect to the stator 50. The rotor shaft 30 has one end thereof exposed to the outside through the front cover 20, and the other end thereof includes a shaft part 32 supported on the inner surface of the rear cap 60; It includes the rotor portion 34 of the cylindrical structure formed integrally with the shaft portion (32).

A pair of bearings 80a and 80b are coupled to the shaft portion 32. That is, the front cover 20 and the rear cap 60 are provided with bearings 80a and 80b for smoothly maintaining the rotation of the rotor shaft 30.

Steps 31a and 31b are formed at one side of the shaft part 32 to stably support each of the bearings 80a and 80b.

In addition, it is preferable that washers 90a and 90b are provided between the shaft portion 32 and the bearings 80a and 80b.

As the bearings 80a and 80b, ball bearings having a simple structure and excellent function are used, and the washers 90a and 90b minimize the interference friction between the rotor shaft 30 and the bearings 80a and 80b, as well as the rotor shaft ( 30) prevents the flow in the axial direction.

As illustrated in FIG. 5, a plurality of magnet coupling grooves 35 are formed on the outer circumferential surface of the rotor shaft 30 at regular intervals along the circumferential direction, and the magnet coupling grooves 35 are magnets 40. In order to facilitate positioning.

On the other hand, the outer diameter of the rotor portion 34 is formed larger than the shaft portion 32 is to improve the balancing (rotation) of the rotor shaft 30 to make the constant speed operation relatively advantageous.

 Magnet (Magnet) 40 is preferably a ferrite sintered magnet, it is divided into four quarters to improve the assembly with the rotor shaft 30 is coupled to the magnet coupling groove 35 of the rotor portion 34. The plurality of magnets 40 are alternately arranged to have different magnetic poles in the circumferential direction.

The stator 50 is a part for maintaining a coil body (not shown) and forming a magnetic path, and is supported on the inner surface of the front cover 20. The number of slots 52 formed in the stator 50 is six, and in forming a coil body (not shown) in one slot 52, a coil is 0.5 mm in diameter and the number of turns is about 110 turns.

On the other hand, reference numeral 54 denotes a tooth in which the coil body is substantially wound.

The stator 50 is supported by the support jaw 22 of the front cover 20 so as to be spaced apart from the front end of the front cover 20.

As a result, a cooling space 24 having a predetermined size may be formed inside the front cover 20, and heat generated by driving of the brushless DC motor may be efficiently cooled.

Support jaw 22 formed in the front cover 20 is only one embodiment for positioning the stator 50 to be spaced apart from the front end of the front cover 20, the stator 50 is the front cover 20 Of course, the various embodiments can be applied within a range that can be spaced apart from the front end of the).

The rear cap 60 is fitted to the rear of the front cover 20, and a cylindrical substrate support 62 in which the shaft 32 of the rotor shaft 30 is inserted and supported is formed at the inner center portion. It has a structure.

On the other hand, the reason why the substrate support 62 protrudes from the bottom surface of the rear cap 60 is that a cooling space 25 having a predetermined size is formed between the outer wall 64 of the rear cap 60 and the substrate support 62. It is to increase the cooling efficiency by forming.

The coupling structure of the rear cap 60 can be appropriately changed within the range capable of stably maintaining the coupling state and easily detachable operation thereof.

The printed circuit board (PCB) 70 serves to control the rotation of the rotor shaft 30.

The printed circuit board 70 is detachably coupled to the upper portion of the substrate support part 62 of the rear cap 60, and a through hole 71 through which the shaft part 32 penetrates is formed in the center portion thereof.

The Hall element sensor 72 is provided on the printed circuit board 70 so as to have a predetermined distance from the rotor shaft 30 and the magnet 40, and the Hall element sensor 72 is positioned at the rotor shaft 30. It serves to detect.

The Hall element sensor 72 is provided on the printed circuit board 70 at regular intervals in the circumferential direction. The number of installation of the Hall element sensor 72 and the arrangement interval thereof can be appropriately adjusted as necessary.

The Hall element sensor 72 is preferably located close to the through-hole 71 formed in the printed circuit board 70. That is, it is preferable to install so as to be spaced apart from the stator 50 as much as possible. This is to minimize the influence of the electromagnetic force generated in the coil body wound on the stator 50.

Of course, since the size of the printed circuit board 70 does not extend to the stator 50, even if the Hall element sensor 72 is installed anywhere on the printed circuit board 70, the coil element (not shown) is not greatly affected. .

As described above, according to the present invention, the brushless DC motor can be compactly constructed by simplifying the internal structure, and the cooling efficiency can be improved through the cooling space.

In addition, the Hall element sensor is spaced apart from the stator, it is possible to eliminate the influence of the coil wound on the stator.

Accordingly, the reliability of the sensing accuracy of the Hall element sensor may be relatively improved, and electrical noise may be minimized by improving the constant speed of the brushless DC motor.

Claims (8)

A front cover having a support jaw formed on an inner surface thereof; A rotor shaft rotatably installed in the front cover; A magnet coupled to the outside of the rotor shaft; A stator provided on an outer side of the magnet and supported on the support jaw so as to form a cooling space in the front cover and spaced apart from the front end of the front cover; A rear cap coupled to the rear of the front cover; A brushless DC motor coupled to the rear cap, the printed circuit board comprising a Hall element sensor. The method of claim 1, The front cover and the rear cap is a brushless DC motor, characterized in that made of a thermally conductive material. The method according to claim 1 or 2, Brushless DC motor, characterized in that the cable outlet is formed on the side of the front cover to draw the inner cable to the outside. The method of claim 1, The rotor shaft is, One end is exposed to the outside through the front cover, the other end is supported by the rear cap; The brushless DC motor, which is formed integrally with the shaft portion, and includes a rotor portion having a magnet coupling groove formed thereon on the outer circumferential surface thereof. The method of claim 4, wherein The rear cap is fitted to the rear of the front cover, the inner central portion of the brushless DC motor, characterized in that the cylindrical substrate support portion protruding the shaft portion is inserted. The method of claim 5, The printed circuit board is a brushless DC motor, characterized in that coupled to the substrate support. The method of claim 1, Brushless DC motor further comprises a bearing coupled to both ends of the rotor shaft. A front cover made of a thermally conductive material having a support jaw formed on an inner surface thereof; A rear cap fitted to the rear of the front cover and having an inner central portion protruding from a cylindrical substrate support; It is installed inside the front cover, one end is exposed to the outside through the front cover and the other end is integrally formed with the shaft portion supported by the substrate support and the shaft portion and the magnet coupling groove is formed on the outer peripheral surface A rotor shaft having a rotor portion; A magnet coupled to the magnet coupling groove; A stator provided on an outer side of the magnet and supported on the support jaw so as to form a cooling space in the front cover and spaced apart from the front end of the front cover; A printed circuit board coupled to the substrate support portion, the center portion having a through hole through which the shaft portion passes, and having a Hall element sensor proximate to the through hole; Brushless DC motor comprising a bearing coupled to the shaft portion.

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