CN1363979A - Brushless DC motor with axial windings - Google Patents

Abstract

Structure of invented brushless electric motor of direct current with axial winding includes engine casing, end cover, bearing, stator, rotator, sensing stator, sensing rotator and driving circuit. The characteristics of the invention are as follows: permanent magnet is installed on the stator, and two helix windings are positioned on middle of the stator; there are even pairs of permanent magnet on the two ends of each winding; outer edge is magnetizer of bracker in tile shape two tubular soft magnets are on outer edge of the rotatory; there are teeth, whose quantity is equal to the quantity of pair of stator pole, on the part of two ends of each soft magnet that is faced to related part of the permanent magnet on the stator; non magnetic isolation tube is installed on the center of rotator; with being supported on two bearings, axis of electric motor positioned on center of the tube; two windings are electrified in turn in positive and negative directions, forming the electric motor running in four beats. The motor possesses merits of simple technical structure, fastness, high utilization rate of windings and large moment.

Description

Brushless DC motor with axial windings

Brushless DC motor with axial windings of the present invention is a kind of brand-new DC Brushless Motor, and its winding is two axial screw spools that have skeleton that are fixed on the stator.Make epitrochanterian tubulose soft magnetic material magnet produce magnetic flux after this axial winding energising, this magnetic flux makes the epitrochanterian tooth relative with stator permanent magnet become magnetic pole, and these magnetic poles and stator produce magnetic action mutually and make the rotor rotation.The sensing rotor that the band permanent magnet is arranged on the rotor.And the sensing stator is arranged on the rear end cap.Hall switch element on the sensing stator is as the position of position transducer detection rotor.Control circuit passes to the corresponding electric current of deciding direction to axial winding by detecting the rotor-position signal that obtains on the sensing stator when rotor is in certain position.Two axial windings pass to the electric current of positive and negative both direction in turn, constitute four and clap operated motor.Usually stator is made the even number number of pole-pairs, as two pairs of utmost points, four pairs of utmost points etc.What enumerate in the present embodiment is four pairs of utmost point motors.For middle and small motor, four pairs of utmost point embodiments are preferred plan.

Accompanying drawing below in conjunction with an embodiment of brushless DC motor with axial windings of the present invention is described further this motor.Fig. 1 is the structural representation of axial winding dc brushless motor, and its external structure part is non-magnetizer casing 9, front end-plate 1, end plate 10.Each bearing 3 of front and back.The rotor outer rim of motor is tubulose soft magnetic bodies 7 and 22, and there is non magnetic isolated tube 18 at the middle part, and this pipe is generally made with non-magnetic stainless steel tube.Rotor center is a steel axle 2, and it is supported on the bearing 3, and bearing 3 is installed on front end-plate 1 and the end plate 10.Stator by permanent magnet 4 and 21, watt shape support 5 and 20 and axially winding 6 and 19 forms, be divided into identical two sections of front and back, the two intersegmental spacer rings 8 of magnetic that have or not separate.The lead-in wire 13 of two windings is connected with control circuit (mark) by magnet 4 and 21 and casing 9, watt shape support 5 and 20 and the line of rabbet joint and the circular hole on the rear end cap 10, the path sleeve pipe 12 of 9 of casings, guide to the outside by hood 11 rear walls.Device has sensing stator 17 on rear end cap 10.Rear-mounted installation at motor shaft has the sense of commentaries on classics rotor 16.The lead-in wire 14 of sensing stator is guided to the outside by the rear wall that path sleeve pipe 15 passes hood 11, is connected with control circuit (not mark).

Fig. 2 is the stator and the rotor magnetic pole part plane of structure figure of brushless DC motor with axial windings of the present invention.Among this embodiment, permanent magnet adopts watt shape structure.In present embodiment Fig. 2, watt shape Nd-Fe-B permanent magnet 2 pastes mutually with soft magnetic bodies 1, is the alternate arrangement of polarity as shown, and its number of pole-pairs is 4, and 4 N utmost points and 4 S utmost points are promptly arranged.Adjacent pole separates with aluminium block 6.As shown in Figure 1, stator all is divided into identical two sections with rotor.If the left side is first section among the figure, the right be second section.The N magnetic pole on first section left side is close to an end of watt shape support 5 that is in first section middle part by soft magnetic bodies 1, and the other end of watt shape support 5 pastes mutually with the soft magnetic bodies 1 on the right again.Arrive the S utmost point magnetic pole on the right.The magnetic line of force arrives the S utmost point from the N utmost point through watt shape support 5.If the magnetic pole on the left side is the S utmost point, the magnetic line of force is from the N utmost point on the right, through the S utmost point on another watt shape support arrival left side, again by rotor tubulose soft magnetic bodies 7 closures.

The width big gap suitable with watt shape support width arranged between adjacent watt shape support, and the purpose that increases the gap is to increase magnetic resistance between two watts of shape supports, to reduce leakage field.An interspace line of rabbet joint wherein is used to draw the stator winding lead-in wire.

As shown in Figure 2, the tubulose soft magnetic bodies of rotor is at 4 teeth of one section formation facing to stator permanent magnet, and the shared circumference angle of tooth and groove equates substantially.The rotor middle part is thick stainless steel tube 4 and motor shaft 5.If use stainless steel shaft, just can remove stainless steel tube.Two sections identical structures of circumferential position of making magnetic pole of stator, and with the circumferential seat of two sections teeth of rotor 1/4 pole span that staggers mutually, 22.5 ° of mechanical angles of half facewidth that promptly staggers.Also can make the rotor tooth circumferential position consistent and make magnetic pole of the stator 1/4 pole span that staggers.

Sensing rotor is an aluminium matter disk, in the radial position facing to Hall switch element on the sensing stator cannelure is arranged one, is uniform-distribution with 4 radians in the groove and is a bit larger tham 22.5 ° arc magnetic sheet.The sensing stator is a printed board that semicircle orifice is arranged in the middle of semicircle, is uniform-distribution with 4 spacings above and is 22.5 ° Hall switch element, curved distribution.Circuit in the printed board couples together these elements, and draws motor body with lead, is connected with control circuit.It is fixed on the rear end cap of motor, and is constant with the relative circumferential position of motor two stators.Hall element is exactly a motor rotor position sensor.

The operation principle of motor is: when a winding of motor passes to the certain orientation electric current, the tooth of this of rotor section soft magnetic bodies one end is the S utmost point, the tooth of the other end is the N utmost point, and the magnetic pole at two ends interacts on the magnetic pole at these two ends and the stator, produces tangential force motor is rotated.

When being located at initial condition, Hall element corresponding to A phase drive circuit is under the sensing rotor magnetic pole, the Hall element that is subjected to sensing is delivered to A phase drive circuit with this signal, energizing circuit work, winding to first section passes to forward current, at this moment on first of rotor section, the tooth on the left side is the S utmost point, the tooth on the right is the N utmost point, and the N utmost point and the S utmost point close on its position and the stator have a circumferential differential seat angle, and magnetic pole interacts and produces tangential force, rotor is clockwise rotated, aim at the stator left side magnetic pole N utmost point until the S on the rotor tooth left side utmost point, rotor reaches settling position, just stops operating.

Under this position, the position transducer of A phase fails, and the A phase current is disconnected.The position transducer of B phase begins effect, and B switches on mutually, and second section stator winding passes to the positive direction electric current.Because second section rotor staggers 22.5 °, the rotor tooth on the right will reach settling position, also need clockwise rotate 22.5 °, so under the B phase current drove, rotor clockwise rotated 22.5 °, reaches second settling position.

Under second settling position, B phase Hall element fails, and the B phase current is disconnected.C phase transducer begins effect, and the C phase current is logical, and first winding passes to negative-phase sequence curent.Because two-stage rotor staggers 22.5 °, so rotor clockwise rotates 22.5 ° again, reaches the 3rd settling position.

Under the 3rd settling position, C phase transducer fails, and D phase transducer begins effect, and the D phase current is logical, and second winding passes to reverse current, and still because of the two-stage rotor tooth staggers 22.5 °, 22.5 ° of the clockwise again rotors of rotor arrive the 4th settling position.

Under the 4th settling position, D phase transducer fails, and A phase transducer begins sensing, A is conducted, and motor turns clockwise, the process that repeats to begin, in turn to the motor windings power supply, motor is just ceaselessly along same direction running in four bat modes for drive circuit like this.

Motor does not wait to reach settling position and just change the road in real work, and this realizes by position of regulating sensing rotor.Change direction with one-time fixing, also can realize with regulating the sensing rotor position.Use if motor is made servomotor, change turning to of motor randomly repeatedly, will realize with directional control circuit.

Brushless DC motor with axial windings of the present invention is compared with traditional radially winding, the DC Brushless Motor that permanent magnet is rotor, it also has following advantage except the common advantage of contactless, the no-spark with DC Brushless Motor, no electromagnetic interference:

1. winding is axial winding, and technology is very simple, and coiling and dismounting all are easy to.

2. winding conductor utilance height, all windings all produce magnetic flux when energising, do not exist winding electric machine two ends radially that the situation of one section invalid conductor is arranged, so the conductor utilance is than general motor improve about 30%.

Axially winding on skeleton, good insulating.Be close to a watt shape support because of skeleton again, near casing, heat radiation also is easier to.

4. permanent magnet is fixed, and becomes the part of stator.This point is different from other all DC Brushless Motor.The fixing easier making of permanent magnet.Because magnet maintains static, and is not subjected to centrifugal forces affect, just can not bring the problem on the intensity, fix also being easier to, than simple and reliable with permanent magnet on rotor.

5. compared with generally radially the winding DC Brushless Motor is next, brushless DC motor with axial windings of the present invention is under the condition of same casing size, and the internal diameter of stator is relatively large, so can produce bigger moment.

Brushless DC motor with axial windings drive circuit of the present invention adopts the dual H-bridge circuit, is the needs of speed governing, and drive circuit adopts the PWM modulation circuit to carry out speed governing.

Claims (4)

1. brushless DC motor with axial windings, its structure is made of casing, end cap, bearing, stator, rotor, sensing stator, sensing rotor, drive circuit etc.It is characterized in that: permanent magnet device is on stator, maintain static moving, the stator middle part is two axial screw spool windings, spiraltron winding two ends are the extremely right permanent magnet of even number, the stator outer rim is watt shape support of soft magnetism, and the rotor outer rim is the soft magnetic bodies of two tubuloses, and relatively partly there is the tooth identical with the stator poles logarithm at each soft magnetic bodies two ends with stator permanent magnet, rotor center has the nonmagnetic substance isolated tube, tube hub device motor shaft.Motor shaft props up on two bearings, and bearing arrangement is on the end cap of two ends, and end cap links to each other with casing.

2. brushless DC motor with axial windings according to claim 1 is characterized in that: the shared circumferential angle of the shared circumferential angle of rotor tooth and groove is identical substantially.

3. brushless DC motor with axial windings according to claim 1 is characterized in that: its stator has identical two sections with rotor, an axial solenoid winding and permanent magnet separately and magnetic conductive tile shape support is arranged in every section of its stator.If two sections rotor tooth circumferential position is identical, then the two ends magnetic pole of the stator will be at 1/4 pole span that circumferentially staggers.Also can make magnetic pole of the stator circumferential position unanimity, and make the two-stage rotor tooth rim to 1/4 pole span that staggers.

4. brushless DC motor with axial windings according to claim 1 is characterized in that: control circuit is supplied with forward or backwards electric current at different time to two axial windings respectively under the control of position transducer, constitute four of motor and clap running.

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