CN1852010B

CN1852010B - Skeleton type brushless DC motor

Info

Publication number: CN1852010B
Application number: CN200510066694A
Authority: CN
Inventors: 李镐在; 李东一; 申铉定
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2005-04-22
Filing date: 2005-04-22
Publication date: 2010-05-26
Anticipated expiration: 2025-04-22
Also published as: CN1852010A

Abstract

This invention relates to a BLDC motor including: a rotor divided into a south pole and a north pole by a magnetic pole separating line, a stator with the rotor mounted on it in air gaps has a first pole shoe, a second pole shoe and a pair of grooves in its internal surface, in which, a part for increasing the air-gap between the rotor and the groove is formed on both ends of the rotor passed by the magnetic pole separating line to reduce the resonance noises by reducing the high level groove torque generated in the drive of the motor when it works.

Description

Skeleton type brushless DC motor

Technical field

The present invention relates to a kind of skeleton (skeleton) brushless direct-current (BLDC) motor, more precisely, relate to a kind of by reducing the BLDC motor that cogging torque reduces the resonance noise.

Background technology

Fig. 1 is the perspective view according to the skeleton BLDC motor of conventional art, and Fig. 2 is the cutaway view according to the skeleton BLDC motor of conventional art, and Fig. 3 is Fig. 2 along the cutaway view that obtains after the III-III line is cut open.

Traditional B LDC motor is by constituting with lower member: be used for the stator 102 that power supply inserts; Be installed in the rotor 104 on stator 102 inner peripheral surfaces at certain intervals, its can by with stator 102 chain rotations; Be installed in rotor 104 central authorities and with the rotating shaft 106 that rotor 104 together rotate, be used for transmitting revolving force to the external world.

Have the printed circuit board (PCB) (PCB) 108 that is used to drive rotor 104 drive circuits in it and be installed in stator 102 1 sides, and PCB 108 is embedded in the PCB guard shield 110.

Stator 102 is made of stator core 116, and wherein composite wafer rivets together after stacked, and wherein first pole shoe 112 and second pole shoe 114 that can hold rotor 104 form an integral body; A pair of bobbin 118 and 120 is fixed in stator core 116; A pair of coil 122 and 124 is wrapped in this respectively on bobbin 118 and 120, and electric current alternately imports this to coil.

For initial driving, for rotor is not zero position alignment with rotor torque, two grooves 126 that are symmetrically distributed with respect to the pivot center of rotor 104 are respectively formed at first pole shoe 112 and second pole shoe 114.

As shown in Figure 4, rotor 104 comprises: an end is the circular magnet 130 in the South Pole for the arctic other end, is benchmark to pass the magnetic pole separator bar that rotor 104 centers radially form; Be installed on the inner peripheral surface of magnet 130 and make rotating shaft 106 be fixed therein the magnet carrier 132 of the heart.

Rotor 104 is installed in the electric machine casing 140, and two bearings 142 and 144 that are used for support motor axle 106 are configured in the electric machine casing 140.

Also be equipped with the position sensor (not marking) of the position of rotation that is used to survey rotor 14 on PCB guard shield 110, this position sensor is installed in detector mounting portion 136.

The operating process of BLDC motor that has above-mentioned structure according to conventional art is as described below.Behind electrical power, position sensor is surveyed the position situation of motor 104 according to the situation of the magnetic pole separator bar 128 on the rotor 104, then on the basis of the result of detection of position sensor, with DC power supply lead to

coil

32 and 34 both one of on.Stator core 116 is excited then, thereby makes magnet 130 rotations.Then, the magnet carrier 132 that is installed on the magnet 130 also rotates, thereby the rotating shaft 106 that is fixed on the magnet carrier 132 also begins rotation.

At this moment wait, utilize groove 126 be formed with respect to first pole shoe 112 and second pole shoe 114 than large-spacing, rotor 140 is not zero position alignment with torque.

But in having the traditional skeleton BLDC motor of said mechanism, cogging torque can inevitably produce, wherein cogging torque be have make with the state of the magnetic energy balance of minimum under the tangential force of the trend of moving.Cogging torque results from the interval between rotor and the stator, and irrelevant with size of current.

In addition, when in rotor rotation process, when the magnetic pole separator bar passed through groove, the size of gaps between rotor and the stator can change thereupon, thereby magnetic flux density is changed.And then can produce the cogging torque of high and low rank (degree).And high level cogging torque is one of main source that produces the resonance noise, the operating noise of the motor that therefore will raise.

To how reducing this problem of noise, at present carried out a large amount of research and obtained certain progress, its basic implementation method has, and improves the magnetic of magnet, or changes the shape of magnet, to reduce vibration, but in the process that reduces alveolar torque, having a problem, is exactly that low-level alveolar torque can be along with the high level alveolar torque (fourth stage, level V ...) together reduce.Just there is a problem in this, because the rotation of motor is to need certain other alveolar torque of level, if rank is low excessively, just can reduce motor performance.

Summary of the invention

Therefore, the object of the invention is to provide a kind of BLDC motor, and it can reduce the high-level alveolar torque that is produced when motor rotates under the situation that guarantees motor performance, thereby reduces the noise that motor produces.

In order to reach these and other advantages and, to have enumerated specific embodiment here, and be described according to purpose of the present invention.A kind of skeleton-type brushless DC B LDC motor is provided, comprises: the rotor that is divided into the South Pole and the arctic based on a magnetic pole separator bar; The stator that rotor is mounted thereon with certain air gap, this stator has first pole shoe, second pole shoe and a pair of groove that is positioned at its inner surface, the air gap formation portion that wherein is used to increase the air gap between rotor and the groove is formed at the two ends of rotor part that the magnetic pole separator bar passes, and this air gap formation portion is by forming from the round-shaped certain width of removing the two ends of rotor part.

Aforementioned and other purpose, feature, aspect and the advantage of the present invention will become more obvious from following detailed description of the present invention with reference to the accompanying drawings.

Description of drawings

Accompanying drawing provides further explanation of the present invention, incorporates and form the part of this specification into, accompanying drawing illustrate embodiments of the invention and and specification be used for explaining principle of the present invention together.

In this accompanying drawing:

Fig. 1 is the perspective view according to the skeleton BLDC motor of conventional art;

Fig. 2 is the cross section view according to the skeleton BLDC motor of conventional art;

Fig. 3 is the cutaway view after Fig. 2 cuts open along the III-III line;

Fig. 4 is the front view according to the skeleton BLDC rotor of conventional art;

Fig. 5 is the cross section view of the skeleton BLDC motor according to the present invention;

Fig. 6 is the cutaway view after Fig. 5 cuts open along the VI-VI line;

Fig. 7 is the front view of the skeleton BLDC motor according to the present invention;

Fig. 8 illustrates the skeleton motor cogging torque of the present invention and traditional skeleton motor alveolar torque chart relatively;

Fig. 9 illustrates high-level cogging torque of the present invention and traditional high-level alveolar torque chart relatively; And

Figure 10 is the chart that noise and the noise generated comparison of traditional skeleton motor in the skeleton motor of the present invention are shown.

Embodiment

Now in detail with reference to an embodiment of the rotor according to BLDC motor of the present invention shown in the drawings.

The embodiment of the rotor of a plurality of BLDC motors can be proposed according to the present invention, a wherein most preferred preferred embodiment will be noted that below.

Fig. 5 is the cutaway view of skeleton BLDC motor according to an embodiment of the invention, and Fig. 6 is Fig. 5 along the cutaway view that obtains after the VI-VI line is cut open.

BLDC motor of the present invention comprises: electric machine casing 1; Be fixed on electric machine casing 1 inboard and be used for the stator 12 that power supply inserts; Be installed in the rotor 14 on the inner peripheral surface of stator 12 at certain intervals, its by with stator 12 chain rotations; The rotation axis 16 that is installed in rotor 14 centers and together rotates with rotor 14 is used for to external world's transmission revolving force.

Wherein have the side that the PCB18 that is used to drive rotor 14 drive circuits 18 is installed in stator 10, and PCB18 is embedded in the PCB guard shield 20.On PCB guard shield 20, also be equipped with the position sensor (not marking) of the position of rotation that is used to survey rotor 14, and this position sensor is contained in the detector mounting portion 52.

Stator 12 comprises: stator core 26, and wherein composite wafer rivets together after stacked, and first pole shoe 22 and be used to hold rotor 14 second pole shoes 24 and form as one wherein; The a pair of

bobbin

28 and 30 that is fixed in the stator core 26; And a pair ofly being wrapped in this respectively to the

coil

32 and 34 on the

bobbin

28,30, the electric current alternate transmission is to coil.

For initial driving, for rotor is not zero position alignment with rotor torque, a pair of groove 36 that is symmetrically distributed with respect to the pivot center of rotor 12 is respectively formed at first pole shoe 22 and second pole shoe, 24 places.

Bearing 50 is installed between rotating shaft 16 and the electric machine casing 10, thereby supports rotation axis rotationally.

As shown in Figure 7, rotor 14 comprises: dish shape magnet 42 to cross rotor 14 centers and to be benchmark with rotor 14 magnetic pole separator bars 40 divided into two parts, is divided into north and south poles; Be fixed on the inner peripheral surface of magnet 42 and make rotating shaft 16 be fixed therein the magnet carrier 44 of the heart.

Here, rotor 14 forms circle, is made of a semicircle arctic and a semicircle South Pole.

Part by excision rotor 14 two ends forms air gap formation portion 60, and magnetic pole separator bar 40 also passes this air gap, and rotor edge is T apart from the width of circular edges.Because this air gap formation portion 60, the magnetic pole separator bar revolves diameter (L) after turning 90 degrees by rotor 14 diameters (L1) located less than rotor 14 relative magnetic pole separator bars 40.

Preferably, air gap formation portion 60 so forms, and makes rotor 14 revolve position (L) after turning 90 degrees from position (L1) that magnetic pole separator bar 40 passes through to magnetic pole separator bar 40 relatively, and the diameter of rotor 14 increases gradually.In addition, preferred, air gap formation portion 60 to the left and right direction from circle center's off-centre 1 to 1.5mm.

When air gap passed through the groove 36 that is formed on the stator 12 when magnetic pole separator bar 40, air gap formation portion 60 allowed to form bigger air gap, thereby can reduce high level cogging torque.

The operating process that has the skeleton BLDC motor of above-mentioned structure according to the present invention will be described hereinafter.

If to electrical power, position sensor is surveyed the position situation of rotor 14, and then on the basis of the result of detection of position sensor, drive circuit is transported in a pair of

coil

32 and 34 one DC power supply.Stator core 26 is magnetized then, and the interaction force between utilization and the rotor 14 rotates rotor 14.

At this moment wait,, when promptly the magnetic pole separator bar passes through the groove 36 of stator 12,, thereby reduce high level cogging torque because rotor 14 has maximum air gap by the air gap formation portion 60 that is formed at rotor 14 when the separator bar of south poles.

Here, cogging torque be a kind of have make with the tangential force of the trend of the state of minimum magnetic energy balance motion, it results from the air gap place between rotor and the stator, and irrelevant with size of current.Because the magnetic energy corresponding to anglec of rotation minor variations is converted into a kind of sine wave, this has just effectively reduced high-level cogging torque.Thereby can reduce the resonance noise.

Fig. 8 is that the cogging torque that the rotor cogging torque of traditional skeleton motor and the skeleton rotor of the present invention are shown is spent journey chart relatively in rotation 360.

Shown in the curve chart of Fig. 8, the cogging torque measured value (P) of conventional motors rotor 104 is compared with the measured value (R, Q) of the cogging torque of rotor 14 of the present invention, and visible the 4th grade or more high-grade cogging torque, radio-frequency component reduce.

Fig. 9 is the chart that the comparison of high-grade cogging torque of the present invention and traditional high-grade cogging torque is shown.Therefrom as can be seen, cogging torque of the present invention (B) will be starkly lower than the cogging torque (A) of conventional motors.Especially when more than or equal to 4 grades of resonance degree when above, cogging torque of the present invention has reduced more than 80% than the cogging torque of conventional motors.

Figure 10 illustrates the noise that produces in the skeleton motor of the present invention and the chart of the noise generated comparison of traditional skeleton motor.Therefrom as can be seen, the noise that produced of the skeleton motor of the present invention noise that will be produced well below the skeleton motor of tradition.

The skeleton BLDC motor that has described structure according to the present invention, its rotor is divided into the South Pole and arctic two parts by a magnetic pole separator bar, a part excision part of simultaneously two ends of rotor, magnetic pole separator bar being passed, thereby form air gap formation portion, expansion is at groove on the stator and the air gap between the rotor, just can reduce cogging torque, thereby reduce the resonance noise.

According to theory of the present invention and principal character, the embodiment of several forms can be proposed, be understandable that, under situation about not being specifically noted, the foregoing description is not limited in previously described content, can be in the claim scope that the present invention stated, it is carried out any modification, that is to say that all modifications, correction or equivalents all should be in the scopes of the claim that the present invention stated.

Claims

1. skeleton type brushless DC motor comprises:

The rotor that is divided into the South Pole and the arctic based on a magnetic pole separator bar; With

The stator that rotor is mounted thereon with certain air gap, this stator have first pole shoe, second pole shoe and a pair of groove that is positioned at its inner surface,

The air gap formation portion that wherein is used to increase the air gap between described rotor and the described groove is formed on the two ends of rotor part that described magnetic pole separator bar passes,

Wherein said air gap formation portion so forms, and promptly the root diameter at the pole line place of passing is less than revolving the root diameter that turn 90 degrees from described magnetic pole separator bar,

Wherein said air gap formation portion so forms, and promptly the root diameter that passes from described magnetic pole separator bar is to revolving the root diameter that turn 90 degrees from described magnetic pole separator bar, and root diameter increases gradually.

2. in the motor described in claim 1, wherein form described air gap formation portion from round-shaped excision certain width by two ends of rotor part that the magnetic pole separator bar is passed.

3. motor as claimed in claim 1, wherein said air gap formation portion to the left and right both direction from the center off-centre 1 of circle to 1.5mm.

4. motor as claimed in claim 1, wherein motor is the two poles of the earth single-phase type motors.