CN1853331A

CN1853331A - A rotor assembly

Info

Publication number: CN1853331A
Application number: CNA2004800271116A
Authority: CN
Inventors: M·J·蔡尔德; P·L·克罗斯利
Original assignee: Dyson Ltd
Current assignee: Dyson Technology Ltd; Dyson Ltd
Priority date: 2003-09-19
Filing date: 2004-09-17
Publication date: 2006-10-25
Also published as: GB0322842D0; GB2406223A; GB2406223B; GB2406147A; GB0321951D0; CN1853333A; CN1853333B; WO2005029680A1; MY137487A; EP1680856A1; JP2007506399A

Abstract

A rotor assembly (1) for an electric machine such as a motor comprises a rotor (3) on a shaft (2) having a bearing (7, 8) at each end portion, the bearings being arranged to rotatably support the rotor and shaft. The assembly further comprises resilient means on the bearings in the form of o-rings (15a, 15b, 16a, 16b) arranged so that, in use, the rotor rotates about its own centre of mass. This reduces wear on the bearings, which may be caused by the rotor rotating about its geometric centre. The rotor assembly may be used in a switched reluctance machine, such as a motor or generator. Air impelling means (4) may be provided on the shaft and arranged, in use, to draw air over at least one of the bearings, in order to cool it.

Description

Rotor assembly

Technical field

The present invention relates to be used for rotor assembly such as the such electrically powered machine of motor or generator.

Background technology

Motor is widely used in many different purposes and is generally used for household implements (domesticappliances).For example, in vacuum cleaner, motor is used for drive fan, and this fan sucks dirty air by dirty air intake.Dirty air flows through the separation equipment of certain form, for example Cyclonic or bag separator, and described separation equipment is eliminating impurities and dust from air-flow, and at last from the air outlet slit air-out.

Switched reluctance machines (switched reluctance machines) becomes more and more popular in recent years.In switched reluctance motor, stator has many group magnetic poles, and described magnetic pole sequentially is energized, with rotor under the relevant influence of magnetic field of every group of magnetic pole, thus a pair of magnetic pole that rotor is met be energized.By between the right magnetic pole of difference, switching fast, might make rotor with very high speed rotation.

The advantage of switched reluctance machines is that they do not use carbon brush, and carbon brush needs periodic replacement, and carbon granule can be discharged into the atmosphere when carbon brush weares and teares.In addition, this motor has quite long useful life, and its speed can not be restricted because of needs keep reasonably brushing the life-span.

The problem that traditional switched reluctance machines may run into is, owing to can realize very high rotary speed of rotator, so the bearing of supporting rotor is easy to wearing and tearing in the stator.This may cause adverse effect to the reliability even the life-span of machine.

Summary of the invention

The invention provides a kind of rotor assembly, it comprises the rotor that is positioned on the axle, and described axle has bearing at every end, and described bearing is arranged to rotatably mounted described rotor and axle, and described assembly further comprises the elastic mechanism that is associated with described bearing.

The configuration of the elastic mechanism that is associated with bearing allows the mass centre rotation of rotor around himself, particularly more than rotor assembly ground resonant speed in.Therefore, rotor assembly can be arranged to the speed rotation with the resonant speed that is higher than rotor assembly, reduces the wearing and tearing on the bearing simultaneously.

In addition, bearing is positioned at the extreme of armature spindle, makes whole rotor assembly to realize dynamic balancing in a plurality of planes.The benefit that this feature provides steadily, peace and quiet move and bearing life increases.

Preferably, each bearing is arranged in the bearing pedestal of being made by Heat Conduction Material.In traditional bearing assembly, bearing is heating in use, and under very high rotary speed even may be overheated.This has limited the rotary speed that such bearing can move traditionally.The heat that the configuration of heat conduction bearing pedestal allows bearing to produce is dissipated.Therefore, bearing can move under the speed of the resonant speed that is higher than rotor assembly.

Preferably, rotor assembly also can comprise the impeller that is fixedly mounted on the described axle, is used as fluid propulsion means in the vacuum cleaner for example to allow rotor assembly.Described impeller is between bearing pedestal, preferably near one of them bearing pedestal.In use,, before being sucked on the impeller, be sucked into earlier at least one described bearing pedestal by the fluid of impeller suction.This has cooling effect to described bearing pedestal, and further helps the heat that dissipates.

Advantageously, each bearing pedestal comprises the mechanism that is used to described bearing that lubricating fluid is provided, to guarantee the whole life period rotor assembly even running at bearing.

Described elastic mechanism can adopt the form of at least one flexible fastening piece, for example is installed at least one O shape circle of each bearing pedestal.Preferably, configuration pair of O shape circle distributes to produce equal load on each bearing pedestal, and each O shape circle is connected to each end of each bearing pedestal.

When electrically powered machine, rotor assembly is arranged in stator module in use, and the position of elastic mechanism makes flexible install (the soft mounting) of rotor assembly in stator module.

The present invention can be applicable to switched reluctance machines, is particularly useful for running at high speed machine, and described high scooter such as per minute 100,000 changes.

Although the following examples are described as the present invention on the motor that is applied in the vacuum cleaner in order to drive fan, but be to be understood that the present invention can be applied to motor and generator simultaneously, be used for the purposes of any kind, and be not limited to vacuum cleaner or field of domestic appliances.

Description of drawings

To the present invention be described with reference to the drawings as an example now, wherein:

Fig. 1 has shown rotor assembly constructed according to the invention;

Fig. 2 is the exploded view of the rotor assembly of Fig. 1;

Fig. 3 is the cutaway view of the rotor assembly of Fig. 1 and 2;

Fig. 4 is the cutaway view of motor that has comprised the rotor assembly of Fig. 1-3;

Fig. 5 is the end view of vacuum cleaner that has comprised the motor of Fig. 4; With

Fig. 6 a and 6b have schematically shown below critical speed and the rotation of the rotor assembly of the present invention when above.

Embodiment

Identical Reference numeral is represented identical parts in specification full text.

Fig. 1-3 has shown rotor assembly constructed according to the invention, and it is generally by Reference numeral 1 expression.Rotor assembly 1 comprises the armature spindle 2 with rotor elements 3.Rotor elements 3 comprises axially stacked steel plate, and it is arranged to form a pair of magnetic pole 3a, 3b.Axle 2 also carrying has the coaxial impeller 4 of a plurality of blades 5, described blade be arranged to tangentially will to be directed to from the fluid stream of axle 2 impeller around.Axle 2 is also carrying the position indicating device of optical encoder dish 6 forms, in use can determine the position of rotation of rotor elements 3.

Bearing assembly

7,8 is located on the axle 2.Each

bearing assembly

7,8 comprises by

bearing pedestal

11,12 and is bearing in the

bearing

9,10 of axle on 2.

Bearing

9,10 is arranged to interference fit (press-fit) on axle, and is press fit in their

bearing pedestals

11,12 separately.Each bearing 9,10 comprises inside race 9a, 9b,

outer race

10,10b and remain on a plurality of balls (ball barings) (not shown) between the described

seat ring.Bearing

9,10 makes rotor 3 can be rotated to support in the stator 13, for example as shown in Figure 4.

Stator 13 comprises one group of steel disc that piles up, and the described steel disc that piles up is arranged to have four inwardly outstanding convex poles.Wherein two magnetic pole 13a, 13b that diameter is relative as shown in Figure 4 each other.Each pole supports winding 14a, 14b, common first phase place that forms of described winding.The magnetic pole (not shown) that another diameter is relative similarly holds winding separately, and described winding is represented second phase place.Each winding 14 comprises around a large amount of numbers of turn of the insulated electric conductors of magnetic pole of the stator (for example more than 50 circles) separately.

According to the present invention, bearing

assembly

7,8 is by elastic mechanism 15,16 supportings.In described embodiment, elastic mechanism is configured to the form of

O shape circle

15a, 15b, 16a, 16b, and described O shape circle is by bearing

pedestal

11,12 carryings.Each bearing

pedestal

11,12 supporting pair of

O shape circle

15a, 15b and 16a, 16b.The every pair of O shape is enclosed residing position roughly corresponding to the end of the bearing in the bearing pedestal separately.Rotor assembly 1 allows rotor assembly 1 in use to find the pivot of himself with respect to this flexible installation of stator module.Therefore, rotor assembly 1 is around the mass centre's rotation of himself, and skew is very little.

Fig. 6 a and 6b show the General Principle that the present invention follows.The continuous thick line of Fig. 6 a is represented rotor assembly 1, and this rotor assembly has bearing

assembly

7,8 at its end.The rotor assembly 1 that comprises bearing is arranged in the rotation of the inside of stator module.Fig. 6 a has shown the state of rotor assembly when rotor rotates below critical speed.Because mass centre's off-center of rotor assembly, armature spindle tends to slight curvature when rotor assembly rotates.Certainly, for clear, the degree of described bending shaft has been exaggerated at this.

With reference to figure 6b, when rotor assembly of the present invention surpassed predetermined resonant speed, the elastic mechanism on the bearing was started working.Described elastic mechanism makes the tip of the axis do orbital motion, as shown by arrows.Like this, rotor assembly keeps straight axle simultaneously, and is offset less around its mass centre's rotation.

In the conventional rotor with hard installation shaft bearing assembly, rotor rotates more than critical speed around its geometric center.Because the bearing rigidity ground in the conventional rotor is installed and can not be done orbital motion, so axle tends to bending.Big out-of-balance force is applied on the rotor assembly, and this causes the radial stress on the bearing again, reduces their life-span thus.

The vibration that this layout of the elastic mechanism related with bearing assembly also causes transmitting between rotation and stationary parts reduces, thereby has also reduced the noise that produces in the machine use.In addition, described rotor assembly is by the process of resonance state, and more attainable process is more steady than so far.

Bearing assembly

7,8 is positioned at the extreme part of armature spindle 2.This feature helps trunnion shaft 2, especially when rotor assembly 1 is in high speed.In traditional layout, its axis is not supported at its end, when rotor during with high speed operation the tip of the axis tend to pushed outwards moving.This effect is especially obvious when rotor is driven with the resonant speed that exceeds rotor assembly.This also causes the core bending of described axle.Therefore, for prevent rotor contact or even the friction stator, traditional machine has sizable gap between rotor and stator.As a result, this efficient to machine has adverse effect.

In rotor assembly of the present invention, the skew of rotor is less than attainable skew so far, therefore can so that the gap between rotor magnetic pole and the stator less than the gap in traditional electrically powered machine.The gap is more little, and the magnetic resistance between stator and the rotor is more little, thereby it is big more to have the power that the motor of given electricity input produces.Therefore, the efficient of machine is improved.

The institute that rotor assembly was rotated more than critical speed encounters problems and is that bearing becomes very hot.So, be used for the bearing pedestal the 7, the 8th of bearing 9,10, heat conductivity.The heat that is produced by bearing 9,10 is dissipated by bearing pedestal 7,8.Therefore, rotor assembly can not make bearing running hot with the longer time of rotation under the very high speed.

Bearing pedestal

7,8 also comprises the

tank

17,18 of fluid (for example lubricating grease) separately, and described container is arranged in use provide lubricated for bearing 9,10.Usually, ball is coated with lubricating grease, and described lubricating grease is along with the time is extruded seat ring.The

container

17,18 of lubricating grease provides lubricated at the whole life period of ball for it.

O

shape circle

15a, 15b, 16a, 16b have limited elasticity to guarantee rotor and rotate and can not contact stator 13 that described contact may cause rotor elements 3, stator or both damages the perforate 19 that provides for it in.Gap between rotor elements 3 and the stator 13 must be little, to guarantee effectively rotor elements to be applied torque.

O shape is enclosed by the tartan manufacturing, for example ethylene propylene diene rubber (EPDM) or silicone rubber.Other suitable material will be conspicuous for the technical staff.

Stator 13 and winding 14 are sealed by plastic material 20 by injection moulding process, and in described injection moulding process, plastic grain is melted, and are injected under pressure then in the die cavity to produce the shape that needs.During this process, the end cap 21 that is used for the perforate 19 of rotor assembly 1 and is used to receive one of them bearing pedestal 11 is formed simultaneously.

Optical encoder dish 6 or photochopper are placed on the armature spindle 2.Described dish is related with optical pickocff, and described optical pickocff is in order to detecting the position of rotation of described dish, thus the position of detection rotor element 3.Signal from optical pickocff is transferred to the controller (not shown).The diameter that encoder dish 6 has is less than the diameter of rotor elements 3, and this helps the manufacturing of rotor assembly.During manufacture, the element of rotor assembly is assembled on the axle, and whole rotor assembly is embedded as in the perforate 19 that rotor elements 3 provides simply, and bearing pedestal 11 is in abutting connection with end cap 21.In the past, the single parts of rotor assembly were carried out balance separately before in being installed to motor or generator, and the rotor assembly of finishing produces less-than-ideal poised state.Yet rotor assembly of the present invention can be finished before the last assembling of motor, thereby whole rotor assembly can be balanced in once-through operation.

Controller is electrically connected to drive circuit, and the winding on each magnetic pole of the stator part is connected to described drive circuit.By in each phase winding in order making current produce torque, thereby between rotor closer to each other and magnetic pole of the stator, produce to attract magnetic force.In each phase place, that phase place near the rotor magnetic pole rotation of magnetic pole of the stator by aligned position before electric current be cut off.

Impeller 4 is along with armature spindle 2 rotation, thereby air is sucked motor.Bearing assembly 8 forms nose cone (nose cone), and this nose cone is positioned at the end of axle 2, the upstream of impeller 4.Therefore, will at first flow through bearing assembly 8 by impeller 4 inhaled airs.The heat that bearing 10 produces is dissipated by heat conduction bearing pedestal 12.Air-flow on the bearing assembly 8 plays a part cooling bearing seat 12.

The inlet 22 of also being furnished with second air-flow that is used for bearing assembly 7 at the other end of axle.The heat that is produced by bearing 9 is dissipated by heat conduction bearing pedestal 11, and described heat conduction bearing pedestal is received the air-flow cooling from inlet 22.

Fig. 5 has shown an example of the vacuum cleaner 30 that can use motor therein., through ozzle 31 and flexible pipe and clava assembly 32 dirty air is sucked in the dust catcher 30 by motor driven impeller 4.Dirty air enters separator 33, and described separator is used for from dirty air separation dirt and dust.Separator 33 can be a cyclone separator, as shown here, and perhaps certain other separator, for example dust bag.Clean air left separator 33 before the motor case that enters the main body 34 that is positioned at dust catcher.In airflow path, the motor fore filter is placed on before the impeller usually, to filter the fine dust particle that any not separated device 33 separates.

In use, (about 100,000rpm) rotary blade 4 with very high speed for motor.The swabbing action of impeller 4 attracts air to pass through dust catcher.Air flows through bearing pedestal then, and is guided by outlet diffusor 23 again by impeller blade 5 and enter scroll (scroll) 24.

Airflow path in, the motor post-filter can be placed on after the scroll 24.Yet the configuration of brushless motor has reduced the requirement for this filter.Air after the cleaning is discharged to atmosphere through suitable outlet from dust catcher then.

The variant of described embodiment will be conspicuous for the technical staff, and mean and fall within the scope of the present invention.For example, although described four utmost point stators, bipolar rotor machine, the present invention can be applied to have on its stator and the rotor machine of other numbers of poles equally, and has the machine of the motor of other size.

Can be configured to form for the elastic mechanism that substitutes is such as the resilient sleeve that is used for housing, compression spring or vibration absorber.Described elastic mechanism can be integrated with bearing pedestal, perhaps can be located between bearing and the bearing pedestal separately.

Rotor assembly of the present invention similarly is applied to motor and generator, and switched reluctance type not necessarily, and can be used in the apparatus that is different from domestic suction cleaner, for example hay mover, air conditioner, hand dryer and water pump.

Claims

1. rotor assembly, it comprises the rotor that is positioned on the axle, and described axle has bearing on every end, and described bearing is arranged to rotatably mounted described rotor and axle, and described assembly further comprises the elastic mechanism that is associated with described bearing.

2. it is extreme that rotor assembly as claimed in claim 1, wherein said bearing are positioned at each of described axle.

3. rotor assembly as claimed in claim 1 or 2, wherein said bearing is arranged in bearing pedestal separately, and described elastic mechanism is attached on each bearing pedestal.

4. rotor assembly as claimed in claim 3, wherein at least one described bearing pedestal is a heat conductivity.

5. as claim 3 or 4 described rotor assembly, wherein at least one described bearing pedestal further comprises and is used for the container of the lubricating fluid of bearing separately.

6. as claim 3,4 or 5 described rotor assembly, further comprise impeller, described impeller is installed on the described axle and between described bearing pedestal with fixed relationship, makes the fluid that is in use aspirated by described impeller attracted at least one described bearing pedestal.

7. as each described rotor assembly among the claim 3-6, wherein said elastic mechanism comprises the O shape circle that is positioned on each bearing pedestal, and described O shape circle is concentric with described axle composition ground.

8. as each described rotor assembly among the claim 3-6, wherein said elastic mechanism comprises the pair of O shape circle that is positioned on each bearing pedestal, described O shape circle is concentric with described composition ground, and described every pair of circle is disposed in roughly the position corresponding to the respective end of the bearing in the described bearing pedestal.

9. the described rotor assembly of arbitrary as described above claim, wherein said elastic mechanism is an elastomeric material.

10. rotor assembly, it is as indicated above basically, and with reference to the accompanying drawings or as shown in the drawing.

11. an electrically powered machine, it comprises the described rotor assembly of each claim as described above.

12. electrically powered machine as claimed in claim 11 further comprises stator, described rotor assembly is arranged in this stator, and described elastic mechanism places between described bearing and the described stator.

13., further comprise being used to detect the mechanism of described rotor with respect to the position of rotation of described stator as claim 11 or 12 described electrically powered machines.

14. electrically powered machine as claimed in claim 13 further comprises the electric winding and the controlling organization that are positioned on the described stator, described controlling organization is arranged to rely on the signal from described position detecting mechanism to encourage described winding.

15. one kind as the arbitrary described electrically powered machine of claim 11-14 kind, it adopts the form of high-speed motor.

16. an electrically powered machine, it is as indicated above basically, and with reference to the accompanying drawings or as shown in the drawing.

17. a cleaning appliance, it comprises as each described rotor assembly among the claim 1-10.

18. a cleaning appliance, it comprises as each described electrically powered machine among the claim 11-16.

19. a cleaning appliance, it is as indicated above basically, and with reference to the accompanying drawings or as shown in the drawing.