CN100536285C

CN100536285C - Grounding brush for relieving current on motor shaft

Info

Publication number: CN100536285C
Application number: CNB2004100811582A
Authority: CN
Inventors: 希扬W·奥; 查尔斯A·金
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 2003-10-06
Filing date: 2004-09-30
Publication date: 2009-09-02
Anticipated expiration: 2024-09-30
Also published as: CN1750363A

Abstract

The invention provides a ground brush for relieving a static charge on a motor shaft, comprising a plurality of filaments which are fixed on an annular framework enclosing the shaft, and tips of the filaments are arranged in a slot restricted by the framework. Conductive powders can be arranged in a channel so as to improve current flow from the shaft to the filaments.

Description

Be used to relax the earthed brush of the electric current on the motor drive shaft

Technical field

The present invention relates to be used for to be controlled at the grounding apparatus of the shaft current that alternating current motor produces, this motor is by variable speed drive device or d.c. motor control, and more particularly, relates to non-contact grounding equipment.

Background technology

Induced electricity the failing to be convened for lack of a quorum of axle occurs in the electro-motor, and usually occurs in the three-phase motor that is driven by the variable speed drive device.The variable speed drive device adopts pulse width modulating technology to change the speed of alternating current motor, thereby under the situation of former employing than expensive d.c. motor, allows to use in actual applications cheap alternating current motor.The defective that use has the alternating current motor of variable speed drive device is: produce higher common-mode voltage (CMV) by the variable speed drive device, this has just increased axle induced current.

The electric current that voltage on the motor drive shaft is inducted flows through bearing, arrives motor framework, ground connection then.When motor running, the resistance that bearing flows through electric current becomes bigger, causes the gathering of electric charge on the axle surface.Through one ofer short duration period, CMV makes accumulation to a high level.When electric charge surmounted the threshold level in minimum resistance path, normally by the ball bearing on the axle, electric energy discharged in other words through the instantaneous outburst of bearing (burst).The machine cut (EDM) of this discharge guiding discharge, this can damage the surface of ball in bearing race and the bearing.Described electrical energy burst produces the fusing pit, forms the particulate that is produced by pit and stays sealed bearing inside.Fusing pit in the bearing and particle matter all disturb the free runner rotation of bearing, and this can cause physical damnification and bearing premature damage.

In order to address this problem, many technology of slowing down have been adopted.Technique known comprises, uses conductive bearing lubricating grease, and bearing is insulated, and uses copper/phosphorus brush and Faraday shield.Adopted a kind of common and cost-effective solution is to use the copper brush that spring is housed that axle is carried out ground connection, and described copper brush provides continuous electric current ground connection.Yet the copper brush wearing and tearing are very fast, thereby require regular, regular maintenance and replacing.In addition, accumulate in oxide on the axle and brush and reduced electric current, and cause electric energy to break out at brush and axle with other barrier between the axle.Because the alternately friction attaching/sliding relation between brush and axle surface, the brush that spring is housed also is easy to vibration.No matter the vibration that is the brush that causes of what reason all can produce undesirable spark.

This area is needed to be a kind of grounding system, and it can be used to cycle time expand effectively, requires minimum maintenance or replacing.

Summary of the invention

The invention provides a kind of grounding apparatus, comprise the conductive filament of a retainer that is arranged in threaded shaft.Brush can be used as a kind of contactless electro-dissociator, to reduce the quantity of electric charge on insulation axle or the insulated rollers.

In one aspect of the invention, the invention provides a kind of electro-motor, this motor comprises: a motor case electrical ground; One motor drive shaft, it is set in the described shell and during described motor operations and is rotated; One electrostatic charge clean-out assembly, itself and the relevant associating of described axle with described shell.Described clean-out assembly comprises: a ring-shaped frame, and it fixes and is electrically connected to described shell around described axle, and described framework qualification one centers on the ring-shaped groove of described axle basically; Some conductive filaments, it is electrically connected to described ring-shaped frame, when described filament enough carefully is in the electric field of the electrostatic charge on the described axle with box lunch, causes ionization, and described filament has the distal portions that is set in the described groove.

In another aspect of this invention, the invention provides a kind of electrostatic charge clean-out assembly that is associated with the axle of motor, described clean-out assembly comprises: a ring-shaped frame, described framework comprise first and second frame elements that limit a ring-shaped groove; Some conductive filaments, it is electrically connected to described ring-shaped frame, and described filament causes when enough carefully being in the electric field with box lunch that ionization, described filament are maintained between described first and second frame elements, and has the distal portions that is set in the described groove.

In still another aspect of the invention, the invention provides a kind of electro-motor, comprising: a motor case electrical ground, it has a panel; One motor drive shaft, it is set in the described shell and extends through a hole in the described panel; One electrostatic charge clean-out assembly, it is configured to around described axle, and be fixed in the described hole of described panel, described clean-out assembly comprises: a ring-shaped frame, it centers on described axle and is fixed in the described hole, described framework comprises first and second frame elements, and they limit one and center on described ring-shaped groove basically; Some conductive filaments, it is maintained between the described frame element, and described filament causes ionization when enough carefully being in the electric field of the electrostatic charge on the described axle with box lunch, and described filament has the distal portions that is set in the described groove.

An advantage of the invention is provides a kind of effective conduction brush assembly, so that reduce the shaft current on the electro-motor.

Another advantage of the present invention provides a kind of grounding apparatus that is used for electro-motor, and it is cycle time expand effectively, and does not need repairing, and safeguards or repairing.

Another advantage of the present invention provides a kind of conduction brush system, and the electric conductivity that it has improvement is used to improve the ground connection performance of equipment.

An advantage more of the present invention provides a kind of grounding apparatus that is used for electro-motor, and it can easily be applicable to the motor of different size.

Considering detailed description hereinafter, after claim and the accompanying drawing, to those skilled in the art, other features and advantages of the present invention will become apparent, and identical in the accompanying drawings label is used to indicate identical part.

Description of drawings

Fig. 1 is the sectional view according to motor drive shaft of the present invention and earthed brush assembly;

Fig. 2 is the partial section that is similar to Fig. 1, shows the second embodiment of the present invention;

Fig. 3 is the sectional view that is similar to Fig. 2, shows the third embodiment of the present invention;

Fig. 4 is a sectional view, shows the fourth embodiment of the present invention;

Fig. 5 is a sectional view, shows the fifth embodiment of the present invention;

Fig. 6 is a sectional view, shows the sixth embodiment of the present invention;

Fig. 7 is a sectional view, shows the seventh embodiment of the present invention;

Fig. 8 is a sectional view, shows the eighth embodiment of the present invention;

Before embodiments of the invention are explained in detail, should be appreciated that the present invention in it is used, be not limited to hereinafter specification or accompanying drawing in CONSTRUCTED SPECIFICATION and the arrangements of components illustrated.The present invention can have other embodiment, and can be implemented in many ways or carry out.And word that is appreciated that herein to be adopted and term are not appreciated that restricted term in order to describe.Adopted herein " by ... form ", " comprising " and their variation are intended to contain the hereinafter listed article of lid and its equivalent, and overage and its equivalent.

Embodiment

Now, more specifically with reference to accompanying drawing, Fig. 1 particularly, label 10 marks one are with the electro-motor shown in the form of partial view, and this motor has one according to of the present invention, can go up a related electric charge clean-out assembly 12 with motor drive shaft 14 runnings of motor 10.Electric charge clean-out assembly 12 can easily be applicable to the motor 10 of the various sizes of the motor drive shaft 14 with various diameters.

Electric charge clean-out assembly 12 centers on axle 14 ringwise.Electric charge clean-out assembly 12 can be arranged in the part of axle 14 and motor case for example between the motor panel 16 with turning round.Assembly 12 is worked serially, thereby is removing the electrostatic charge that accumulates on the motor drive shaft 14 between the on-stream period of motor 10.

Electric charge clean-out assembly 12 comprises a brush assemblies 18, and this brush assemblies has many independent fiber filaments 20, and they can be installed individually around axle 12 along circumference or bunchy ground is installed.Every filament 20 all is thin hair-like structures, and by carbon fiber, stainless steel, conductive plastics be acrylic acid or nylon fiber for example, thereby or any other can provide diameter enough little in electric field induced electricity from conductive fiber shape filament constitute.Preferably, in the scope of the diameter of filament 20 between about 5 microns to about 10 microns.

Filament 20 or its bundle take the shape of the letter U, and around an annular slab 22, make the internal diameter of the relative distal portion extend through template 22 of filament 20.Perhaps, the bundle of individual filament 20 or filament 20 is set on the one or both sides of plate 22, thus the internal diameter of one distal portion extend past template 22 only.Template 22 is by metal, and conductive plastics or other electric conducting material are made.Filament 20 or its bundle are by one deck electroconductive binder, and adhesive tape or other mode (not shown) that is fit to are fixed on the plate 22.Be used between template 22 and filament 20 or its bundle at the band that has adhesive on the both sides.Perhaps, filament 20 is directly being pasted the surface of template 22 and is being placed, and wherein band is attached on the outer surface.

The assembly of filament 20 and template 22 is maintained in the circular passage 24 that is formed in the annular frame 26, and described framework comprises the first and second

annular frame elements

28 and 30 together fixed to one another and that roughly extend along the opposite side of brush assemblies 18.First and

second frame elements

28 and 30 the surface of facing are formed as and receive the template 22 that has filament 20 on it between them, form groove 24 simultaneously, and the distal portion of filament 20 is located in wherein.Frame element 30 is by metal, conductive plastics, or other electric conducting material makes, and be electrically connected on the brush assemblies 18.Can make by the material that is similar to frame element 30 as the frame element 28 that brush assemblies 18 is remained on the holding element in the frame element 30, also can for example rubber or thermoplastic be made by insulating material.

In the embodiment shown in fig. 1, each part of assembly 12 is assembled together by interference fit.Brush assemblies 18 is positioned in second frame element 30, and first frame element 28 snugly is assemblied in the outward flange 32 of second frame element 30, and pastes mutually with brush assemblies 18.Then, by flange 32 being pressed in the opening in the panel 16 that centers on axle 14, described pre-installation clean-out assembly 12 promptly is fixed, and the shoulder 34 of its middle frame 26 is meshed with the outer surface of panel 16.Also can use assembly 12 is fixed on other device on the motor 10, for example, extend through framework 26 and be fixed on screw (not shown) in the panel 16.Thereby clean-out assembly is electrically connected on the motor case by panel 16, thereby is grounded.

Filament 20 can directly contact with axle 14, as earthed brush, is used for directly electric charge being transferred to clean-out assembly 12 from axle 14.Filament 20 can also have minimum interval with axle 14, like this, when an electric field when accumulating in the charge generation of axle on 14, just produce an ionized field, thereby allow electric charge to transfer to filament 20 indirectly from axle 14.In another layout that is fit to, when motor 10 was in static or slower speed, light filament 20 contacted with axle 14.Between starting and operating period, along with the increase of axle 14 speed, air stream makes filament 20 leave axle 14.Eliminate or reduce the time of the CONTACT WITH FRICTION between filament 20 and the axle 14, just reduced wearing and tearing, thereby prolonged the life-span of filament 20.Framework 26 be electrically connected, and before forming electric arc, the electric charge that accumulates on the axle 14 is transferred to ground by scavenge unit 12.

Those skilled in the art's easy to understand is suitable for remaining on brush assemblies 18 around the axle 14 and being fixed on the motor panel 16 for the multiple different configurations of framework and frame element.

Axle electric charge clean-out assembly of the present invention can be used in combination with other function element of motor 10.Fig. 2 shows one embodiment of the present of invention, and wherein, a bearing insulation seal 40 is maintained on the axle 14 by a framework 42.Framework 42 can comprise that first frame element 44 and that is similar to frame element 28 has improved second frame element 46 of an extension 48, and described extension forms the container that keeps seal 40.Brush assemblies 18 and seal 40 are positioned in the framework 42, and then, whole assembly is press-fitted in the panel 16.Replace shoulder, the outward flange 50 of frame element 46 is provided with one or more dimples or other rat, is used for cooperating with the outer surface of panel 15.

Fig. 3 shows another embodiment of the present invention, and wherein, framework 54 has a frame element 56, and frame element 56 comprises an extension 58, does not have bearing seal in this extension.For effective ionization, extension 58 is provided with enough spaces around filament 20, and element 58 is easy to be made by metal stamping technology.

Fig. 4 shows the of the present invention favourable structure that is easy to make.One metal or conductive plastics outer shroud 60 are configured to such size, that is, be fixed in the motor panel 16 by interference fit.The thermoplastics of symmetry or

rubber retaining ring

62 and 64 are configured to be remained on two that encircle in 60 by interference fit ground.Brush assemblies 18 is maintained between the

symmetrical retaining ring

62 and 64 in the outer shroud 60.

In order to improve the performance according to clean-out assembly of the present invention, trickle conductive powder 70 is set in the ring-shaped groove 24, around the distal portion of filament 20.The powder that adopts for example, has carbon dust or other metal dust.Particle 70 can use dryly.Yet, as fruit granule 70 and various types of silicone oil, synthetic hydrocarbon oil, ester oil, fluorocarbon oil, ether oil, polyethylene glycol oil, mineral oil or similar substance mix, and the pasty mass that is obtained by their is easier to be maintained at around the distal end of filament 20.

Fig. 5 shows the embodiment that is similar to Fig. 4, yet has the particle 70 around filament 20 between symmetric element 62 and 64.Find the filament of about 100 micron-scales 20 and have less than the conductive particle 70 of about 50 micron diameters and can work effectively.

Ring

62 and 64 has an internal diameter, thereby Min. ground separates with axle 14.Like this,

ring

62 and 64 can seat on axle 14, thereby can not rub.Yet axle 14 and the distance of ring between 62,64 are enough little, thereby from the grease of bearing be positioned at similar substance on axle 14 inboards, and from dust or other dirt of axle 14 outer ends, be not easy to move to outside the ring 62 and 64.So just protected filament 20 not contaminated.

When using

conductive powder

70,20 electric current can produce by two kinds of different institutions from motor drive shaft 14 to filament.First kind of mechanism is the air ionization around filament tip.Another kind of mechanism contacts with 14 physics by powder 70, being in contact with one another of each particle of powder 70 and contacting of particle 70 and filament 20.When motor drive shaft rotated, filament 20 was lifted away from the axle surface by air-flow.Yet even Zong wear and tear on the filament, even make and also can not take place when axle 14 is in to contact when static, this equipment also both can work on by the electric current that flows through conductive powder 70 again by ionization.

Motor drive shaft preferably is not circular.When axle rotated, the distance from the far-end of filament 20 to the axle surface can change, and may be excessive, thereby ionization is around the air of filament 20 effectively.When trickle conductive powder 70 was placed in the gap between the far-end of axle 14 surface and filament 20, electrically conductive particles had compensated the variation of clearance distance by filling this gap.Therefore, described conductive powder has produced a kind of condition, and filament tip keeps fully near powered surfaces, so that continuous air ionization to be provided under this condition.In addition, produced the motion of particle owing to electric attraction in filament tip towards ground.This movement of particles has also increased the electron transfer from the rotating shaft to the filament tip.

Fig. 6 shows another embodiment of the present invention, and it is similar to embodiment shown in Figure 5.Except the structure that is similar to Fig. 5, the embodiment of Fig. 6 comprises that also one encircles 72 in thin between 14 of filament 20 and axle.The setting of interior ring 72 more effectively is contained in conductive powder 70 in the groove 24.In order to prevent that more effectively pollutant from arriving the groove around filament 20,

annular groove

74 and 76 is separately positioned on the inner surface of retaining ring 62 and 64.One or more taps 78 are set in each

ring

62,64, there is shown a this tap 78 in ring 64.Pollutant between axle 14 and retaining

ring

62 and 64 is trapped in

groove

74 and 76, and discharges by tap 78 by centrifugal force.

Fig. 7 shows another embodiment of the present invention, and it is arranged to be parallel to the axis of motor drive shaft.The filament 80 of present embodiment is roughly parallel to axle 14 axis, rather than the far-end that is installed into them is facing to axle 14, and by individually or bunchy ground locate around stator 82.Filament 80 is pushed down stator 82 by a retaining ring 84 and is fixed.One rotor 86 is with axle 14 rotations.The relation that

stator

82 and 86 one-tenth of rotors are faced, and filament 80 extend through stators 82, and entering surface is in the groove 88 in the surface that is limited at rotor 86 of stator 82.Conductive powder 90 is placed in the groove 88, around the far-end of filament 80.Rotor 86 and stator 82 are assembled in the shell 92, and it is press-fitted in the ground connection motor case 94.The flange 96 of shell 92 is stacked on the rotor 86.

Another embodiment of the present invention is shown in Figure 8.Electric charge clean-out assembly 100 is positioned in between axle 14 rotor rotated 102 and its radially outer track ring 104.A plurality of filaments bundles 106 that every bundle comprises a plurality of independent filaments 108 are maintained in the component framework, between a public frame plate 110 and a female frame plate 112.Preceding sealing plate 114 and back sealing plate 116 are set up respectively.One suspension ring 118 and O shape ring 120 are set at outside the preceding sealing plate 114.Conductive powder 122 is sealed in the groove 124 that is limited by public plate 110 and motherboard 112.Conductive strips or thin conducting ring can be used between track ring 104 and the public plate 110, to improve the conductivity by assembly 100.As shown in Figure 8, all elements of this embodiment are configured to be press-fitted or snap fit, thereby have improved the simplification of assembling.

Removing equipment according to the present invention can be used to the through-put power signal of telecommunication as a collecting ring.Equipment according to the present invention also can be used to protect bearing or other whirligig of motor as bearing isolator.Removing equipment of the present invention is as the contact earthed brush, also as contactless ionization device.Like this, even wear and tear, according to clean-out assembly of the present invention also continuous operation effectively.

Aforesaid all changes and change are in the scope of the present invention.Be appreciated that invention disclosed herein and that limit is prolonged and above-mentioned or might make up from two or more institute of literal and/or conspicuous each part of accompanying drawing.These all various combinations have constituted various possibilities of the present invention aspect.Embodiment as herein described has set forth the known optimal mode that is used to carry out an invention, and will make other those skilled in the art can use the present invention.Claim will be interpreted as comprising prolongs and possible embodiment that prior art allowed.

List in the various part of the present invention claim hereinafter.

Claims

1. electro-motor comprises:

One motor case electrical ground;

One motor drive shaft, it is set in the described shell and during described motor operations and is rotated;

One electrostatic charge clean-out assembly, it is related with described axle and described shell, and described clean-out assembly comprises:

One ring-shaped frame, it is around described axle, and is fixed and is electrically connected to described shell, and described framework limits a ring-shaped groove around described axle;

Some conductive filaments, it is electrically connected to described ring-shaped frame, and described filament causes ionization when enough carefully being in the electric field of the electrostatic charge on the described axle with box lunch, and described filament has the distal portions that is set in the described groove.

2. motor as claimed in claim 1, described clean-out assembly also comprises: an annular slab, described filament partly surrounds described plate, and the distal portions of described filament extends into described ring-shaped groove.

3. motor as claimed in claim 1 also comprises the conductive powder that is placed in the described ring-shaped groove.

4. motor as claimed in claim 3, described conductive powder and silicone oil, synthetic hydrocarbon oil, ester oil, fluorocarbon oil, ether oil, polyethylene glycol oil or mineral oil are so that form a kind of paste.

5. motor as claimed in claim 3, described clean-out assembly also comprises: an annular slab, described filament partly surrounds described plate, and the distal portions of wherein said filament extends into described ring-shaped groove.

6. motor as claimed in claim 5, described filament has enough length, makes that at least when remaining static for described, the end of described filament and described being coupling are touched.

7. motor as claimed in claim 5, described framework comprise an outer shroud and are arranged on first and second retaining ring on the opposite side that is positioned at described plate and described filament in the described outer shroud.

8. motor as claimed in claim 7, described framework further comprise an interior ring that covers described ring-shaped groove.

9. motor as claimed in claim 7, each of described first and second retaining rings all have in the face of an annular groove of described axle and are used for from the tap of described groove emission.

10. motor as claimed in claim 1 has the rotor with described axle rotation, and described filament is arranged to be arranged essentially parallel to described axle, and the distal portions of described filament is facing to described rotor.

11. motor as claimed in claim 1, described filament has enough length, makes that at least when remaining static for described, the end of described filament and described being coupling are touched.

12. motor as claimed in claim 1, described filament is arranged bunchy.

13. motor as claimed in claim 1, described ring-shaped frame comprises first and second frame elements, and in the described frame element one is fixed in the described frame element another.

14. motor as claimed in claim 1, described framework comprise an outer shroud and are arranged on first and second retaining ring on the opposite side that is positioned at described filament in the described outer shroud.

15. an electrostatic charge clean-out assembly that is associated with the axle of motor, described clean-out assembly comprises:

One ring-shaped frame, it is around described axle, and is fixed and is electrically connected to the shell electrical ground of described motor, and described framework comprises first and second frame elements that limit a ring-shaped groove;

Some conductive filaments, it is electrically connected to described ring-shaped frame, described filament causes that ionization, described filament are maintained between described first and second frame elements when enough carefully being in the electric field of the electrostatic charge on the described axle with box lunch, and has the distal portions that is set in the described groove.

16. clean-out assembly as claimed in claim 15 also comprises an annular slab, described filament partly surrounds described plate, and the distal portions of wherein said filament extends into described ring-shaped groove.

17. clean-out assembly as claimed in claim 15 also comprises the conductive powder that is placed in the described ring-shaped groove.

18. clean-out assembly as claimed in claim 17, described conductive powder and silicone oil, synthetic hydrocarbon oil, ester oil, fluorocarbon oil, ether oil, polyethylene glycol oil or mineral oil are so that form a kind of paste.

19. clean-out assembly as claimed in claim 15, described framework also comprise an outer shroud and are arranged on first and second retaining ring on the opposite side that is positioned at described filament in the described outer shroud.

20. clean-out assembly as claimed in claim 19 also comprises the conductive powder that is placed in the described groove.

21. clean-out assembly as claimed in claim 20, described framework further comprise an interior ring that covers described ring-shaped groove.

22. an electro-motor comprises:

One motor case electrical ground, it has a panel;

One motor drive shaft, it is set in the described shell and extends through a hole in the described panel;

One electrostatic charge clean-out assembly, it is configured to around described axle, and is fixed in the described hole of described panel, and described clean-out assembly comprises:

One ring-shaped frame, it centers on described axle and is fixed in the described hole, and described framework comprises first and second frame elements, and their limit a ring-shaped groove around described axle;

Some conductive filaments, it is maintained between the described frame element, and described filament causes ionization when enough carefully being in the electric field of the electrostatic charge on the described axle with box lunch, and described filament has the distal portions that is set in the described groove.

23. electro-motor as claimed in claim 22 also comprises the conductive powder that is placed in the described groove.