CN105151962A - Electromagnetic braking technique for elevator traction machine - Google Patents

Abstract

The invention relates to an electromagnetic braking technique for an elevator traction machine. An electromagnetic brake can improve the braking ability of the elevator traction machine, and the electromagnetic brake is composed of a permanent-magnet synchronous motor of the traction machine and a controller which is additionally arranged on the permanent-magnet synchronous motor. The controller comprises two automatic switches and a control circuit, and the automatic switches and the control circuit are arranged on a control cabinet. The two automatic switches can respectively control direct current to appropriately enter and exit the two ends of a winding. The conditions for the electromagnetic brake to control (trigger) the automatic switches are door opening position signals of a lift car door limiting switch, non leveling signals, normally-closed signals of an overhauling relay and normally-closed signals of a band-type brake contactor. The electromagnetic brake serves as an auxiliary brake of the permanent-magnet synchronous gearless elevator, and the braking torque can reach more than 2/3 of the nominal torque. The electromagnetic brake is small in invest, small in size, safe, reliable, economical, practical and convenient to install and detect. Compared with general power generating braking and energy consuming braking, the electromagnetic braking technique avoids inertial motion and can brake the elevator in a static or slow-moving state. The electromagnetic braking technique also can emergently brake an escalator or an automatic walkway and is also suitable for braking requirements of other permanent-magnet electric motor traction systems.

Description

A kind of electromagnetic brake technology of elevator traction machine

The present invention relates to permanent-magnet synchronous elevator auxiliary brake mode, reliably can prevent a kind of safety measure of car accidental movement.

As the first in the world elevator big country, in recent years but recur elevator shearing accident, to such an extent as to have " life week taken by force by elevator ", ' saying of " people being eaten by elevator ".Failure-free braking is the safety control that elevator runs.Known elevator brake is normally closed (must establish lock by cable) formula machine--the electric-type drg (friction-type) with compositions such as electromagnet, coil, retarding springs installed on its towing machine.Nearly ten years, the anodontia rotating technique of the permanent-magnet synchronous of energy-conserving and environment-protective obtains development at full speed and almost all instead of tooth transmission traction field.And its friction-type machine--electric brake remains as classical architecture, Yet-have is there are no new braking mode.Because car accidental movement accident is very serious to passenger's injury, the unfailing performance of this classical drg must be attributed to.Seem the anodontia transmission elevator of perfect permanent-magnet synchronous and worldwide receive serious challenge.

For this reason for accidental movement of elevator cage protection problem, basic standard " elevator manufacture and the installation safety standard " GB7588-2003 of elevator is among amendment is discussed warmly.Magazine " Chinese elevator " 2015 the 13rd phase organizes " protection of car accidental movement " (UCMP) special seminar for this reason; discussion scheme almost concentrates on and requires aspect to the Detection & Controling of car accidental movement; do not see the anatomy to " accidental movement " cause, do not see that a complete feasible scheme is put into effect yet.

The reason carefully analyzing car accidental movement only has two: one to be operate against regulations to cause equipment to lose braking potential; Two is design kinetic force inadequate natural endowments, i.e. equipment deficiency.The former is had greasy dirt by short circuit, brake wheel as door lock electrical node, and drg cannot normally work; And although the errorless still lock of the latter's drg action does not live car, be exactly that lock torque is too little undoubtedly.Look back worm-gear-worm towed elevator car and seem there is no accidental movement accident like this.As everyone knows, worm-gear-worm machine also has auto-lock function, and exactly for the load of elevator potential energy, this is safest just.Now with Fig. 1, the strained condition of towing machine when braking is shown.Wherein: W is counterweight mass, Q is car mass, P car load, F are the compressive force of brake spring.Known counterweight designing quality:

W＝Q+KPe

In formula, K is equilibrium factor, and Pe is rated load units/kg.During car stationary, the power torque on traction sheave and lock torque reach balance.Kinetic moment Md is the formation of making a concerted effort of counterweight and car:

Md＝[(Q+P-W]R＝(P-KPe)R………(1)

Braking torque Mz is that braking force F is formed the friction that brake wheel produces, and this friction force is always contrary with sense of motion, settles accounts on traction sheave to be:

Mz＝F·f·i ₁·i ₂·r·r/R………(2)

In formula: f is the friction coefficient of friction lining to brake wheel; i ₁for lanyard ratio, be 1 herein; i ₂for the reduction ratio of towing machine; R is brake wheel radius; R is traction sheave radius.

Permanent-magnet synchronous toothless traction machine, i2 is 1; R/R ≈ 1; , its lock torque should be: have during Mz=Ffr braking: Mz >=Md and Ffr >=[P-KPe] R

∵ F >=[P-KPe] R/fr establishes equilibrium factor K=50%, and when zero load, P=0,

∴F≥-0.5Pe·1/f·r/R＝0.5pe/f……….(3)

Friction coefficient f is far smaller than 1, and only having the friction coefficient of rubber to cast iron maximum, is 0.8, and the combination in any friction coefficient between other material is all much smaller.If consider certain safety factor again, so braking potential may exceed rated load value.The author notices that the drg of certain load-carrying 1000kg towing machine marks braking force 6000N, even also has 3400N, well below the computing value of (3).

According to GB7588-2003 " elevator manufacture with install safety standard " 12.4.2.1 article " when car be loaded with 125% specified and run downwards with command speed time, operational brake should be able to make towing machine shut down." seem this regulation very sternly, the rich degree (safety factor) of lock torque Mz reaches 25%, is it much of that? look to also have which influence factor on earth in practical application:

A. friction coefficient f is by the impact of temperature, pressure, dust and dirt, particularly meets greasy dirt and skids, and causes f value lower barrier rapidly;

When b. doing braking potential test, must be adjust to reach requirement in optimum regime; But use when long, hold-down nut loosens a little all can reduce spring pressure;

C. only can reduce along with elevator long-time running drg opens lock electromagnetic force, there will be brake wheel heating and even to stop phenomenon.This needs adjustment, and the way saved trouble most turns down spring pressure exactly.Although do operation of declutching smoothly like this, also eat up the margin of safety of lock torque, become hidden danger.

As can be seen here, above-mentioned is all negative factor, and machine-electric brake reliability is had a greatly reduced quality.For the old-fashioned towing machine having speed reduction gearing, increase square function owing to slowing down, as worm-gear-worm reductor, reduction ratio reaches more than 20 times, and its brake wheel is much smaller than traction sheave again, and above-mentioned negative factor is just covered by fully making up; The permanent-magnet synchronous toothless traction machine of energy-conserving and environment-protective makes us intoxicated, and have forgotten it and also eliminated the effect of increasing square while elimination reductor, these negative factors are by that rich degree approach exhaustion of 25%.The energy-efficient of visible anodontia machine sacrifices due safety performance, and existing permanent-magnet synchronous elevator braking potential is obviously not enough, particularly low-speed toothless elevator.

The present invention be directed to existing deficiency and announce a kind of auxiliary stop scheme---namely utilize the permasyn morot of transmission main frame to add cartridge controller and direct supply and form a new electricity-magnetic brake.Its principle is:

Because permasyn morot is made up of the rotor of permanent magnet poles and the stator laying three-phase symmetric winding, lanyard wheel and rotor coaxial just create three phase rotating field and drag rotor and traction sheave synchronous rotary when connecting three phase mains.If stator is accessed direct supply, so stator will resemble electromagnet rotor generation effect.It is made to produce stable braking force, then must set up stable suction field between stator and rotor, so access direct current (DC) should follow this rule, namely ensure the magnetic pole logarithm that stator is the same with rotor, that is stator circumference is formed and rotor permanent magnetic pole stabilizing magnetic field one to one.According to the magnet principle that there is a natural attraction between the sexes, permanent magnet poles rotor is just firmly held by the stator electromagnet field of correspondence, gets off even if also car is reliably parked.By above-mentioned rule wiring as Fig. 2, Fig. 3, and its lock torque is by the torque rating more than 2/3.

Required controller comprises the circuit card composition of two automatic switchs and centralized control signal.Two automatic switchs control direct current (DC) respectively in good time into and out of the two ends of winding, also suitably will control intensity of current (gradient) to meet the needs of brake action simultaneously.(triggering) signal controlling automatic switch action should gather the logical condition controlling direct current (DC) connecting and disconnecting, to ensure that automatic switch drops in good time, prevents misoperation.

As the auxiliary braking of elevator, its condition controlling (triggering) automatic switch has:

A gate opening-wide state---get gate limit switch (being in enabling) position signal.Door-opened elevator allows passenger come in and go out, now implicit dangerous, must be careful, strictly guards;

B is not or not enabling district---and layer signal of making even is non-.The action in a district is left in this measure monitoring.Enabling district is the scope of upper and lower 20 centimeters of level position.In enabling district, short distance moves and can not cause safety misadventure, also can hold hidden; And movement is only accident outside enabling district, be the root of shearing accident, should stop immediately;

C elevator operation switch is beaten in " automatically " position---or get the normally closed signal of maintenance relay.This condition gets rid of overhauling elevator operating state, and jointly confirm that car is surprisingly opening the door movement with A, B, namely elevator is in major accident state, should start auxiliary stop immediately, and Accident prevention occurs;

D machine-electric brake is in power-off band-type brake state---get the normally closed signal of band-type brake contactless switch.Judge that elevator is with through stop thus, electrical motor has departed from source of AC, and power supply conflict can not occur instant direct current of connecting;

The condition Z controlling (triggering) brake switch can be defined as:

Z＝A·B·C·D

Like this, once foundation brakes lost efficacy, no matter elevator is upstream or downstream states, this device all can reliable stop, and elimination car opens the door mobile accident, plays safety guard-safeguard effect.

Above-mentioned control signal can be focused in one piece of printed board, be introduced by connection terminal, combine, form integrated signal Z and go to control automatic switch.Automatic switch, as selected solid switch, so just can be set together with integrated signal circuit, and is installed in machine room elevator control box, to facilitate installation, to detect.

Device security is guaranteed for preventing AC and DC electrical conflict; desirable run signal is non-; namely two switches run in normally closed signal and the controller of contactless switch carry out chain, thus the double protection of formation direct current (DC) input for safety, guarantee that DC switch does not have and conflicting of running that contactless switch closes a floodgate simultaneously.

Direct supply can share one with machine-electric brake, should adjust and whether should increase capacity, but the DC current values of answering attentional manipulation to flow into phase winding must not exceed its phase current nominal value.

Be different from conventional dynamic brake and resistance braking, this braking scheme is without the need to inertia motion, but it is parked to have an effect under static or slow motion state.Be the Application and Development to the electromagnetic braking ability under a kind of specific operation of permasyn morot, also can say it is supplementing of permagnetic synchronous motor utility function.Also can make the escalator of permagnetic synchronous motor dragging or the accident brake of automatic street crossing, also be applicable to the demand that other permanent magnet motor dragging systems are parked.Its lock torque can reach the torque rating of more than 2/3.Less investment, volume is little, not only safe and reliable but also economical and practical, install, detect also very convenient.

Must shock counter measure be considered, particularly apply under fast state.Strength under shock depends on that factor is too many, as DC amperage, leading edge gradient, electrically and mechanical system inertia and brake system can ability to bear etc., set up according to actual needs at last.

Accompanying drawing explanation

Fig. 1 is elevator power diagram of gears, demonstrates the strained condition of towing machine when braking.Wherein: W is counterweight mass, Q is car mass, P car load, F are the compressive force of brake spring.

Fig. 2, Fig. 3 are the schematic diagrams obtaining stop moment with permagnetic synchronous motor, and figure comprises motor stator three-phase windings, controller (being made up of two automatic switchs and control signal circuit card), direct supply three part form and current direction.Wherein, Fig. 2 is to two phase winding energisings, and Fig. 3 is three phase winding energisings.

Claims (4)

1. an electro-magnetic braking device, the permanent magnet motor of towing machine is passed to DC current in good time and namely become elevator failure-free auxiliary braking facility, it is characterized in that: access direct current should ensure the magnetic pole logarithm that stator is the same with rotor, that is stator circumference is formed and rotor permanent magnetic pole stabilizing magnetic field one to one.

2. electro-magnetic braking device according to claim 1, is characterized in that: two automatic switchs control direct current (DC) respectively in good time into and out of the two ends of winding, also suitably will control intensity of current to meet the needs of brake action simultaneously.

3. electro-magnetic braking device according to claim 1, is characterized in that: controlling (triggering) condition Z can be defined as:

Z＝A·B·C·D

Wherein, A---gate limit switch (being in enabling) position signal

B---flat bed signal is non-

C---the normally closed signal of maintenance relay

Its normally closed signal of D---band-type brake contactless switch.

4. electro-magnetic braking device according to claim 1, is characterized in that: this braking scheme is without the need to inertia motion, but it is parked to have an effect under static or slow motion state, is applicable to the demand that other permanent magnet motor dragging systems are parked.