Shuttle Car

By:Harshit Mishra

Abhik Chatterjee

Shuttle car is a large heavy duty unit ,designed to carry maximum payload at high speed.

It collects the coal from continuous miner working at the face and supplies to Feeder breaker or mine cars or belt conveyors.

Introduction

The car has four wheel positive drive and four wheel hydraulic operated steering , which provides maximum traction potential with a minimum turning radius.

It contains hydraulic pumps, driven by a separate electrical motor to power the cable reel , steering and conveyor elevating functions.

At discharge end a chain and flight conveyor is fitted which can be elevated by hydraulic cylinders.

Design

Pump motor compartment

Cable reel compartment

Traction motorControllerConveyor motor

Conveyor reducer

Operatorcompartment

Design

Traction drive Hydraulic system Electric System Steering Arrangement Conveyor Drive Cable reel mechanism

Main Components

The 2 wheel on each side of car are driven by 2 separate traction motors through spur gear reducers , which are coupled to the receiving end wheel drive units by universal drive shafts.

The receiving end drive units are connected to similar units at the discharge end of the car by universal drive shafts.

Traction Drive

1.Drive shaft 4.reducer2.Universal joint 5.Wheel unit3.Traction motor

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3

5

4

1

Traction Drive

Of the four wheel drive units consists of a bevel gear set , driving a ball type constant velocity joint , which in turn drives a planetary gear set within the hub.

There is no transverse connection between the drive elements so that no mechanical differential is needed.

Each traction drive carries an enclosed wet brake unit coupled directly to gearbox.

This system regulates the flow of hydraulic fluid at system pressure to raise and lower the conveyor, extend and retract the steering cylinders, releases of brakes and power the cable reel.

Electric motor must be energised for starting the pump before any hydraulic function is operated.

Hydraulic System

Hydraulic Pump The pump is a two-suction , gear style unit. Each section of two-stage pump have

separate set of gears . The gears in the 46 lpm section are wider , thus having a larger capacity.

The pump is splined and bolted directly to the pump motor.

The high volume stage of pump delivers (46LPM) fluid to cable reel valve(Since here, shuttle car is in stationary mode, cable reel motor will be in stalled position) & conveyor elevating valve.

The Low volume Stage delivers (34LPM) fluid to hydraulic cylinders in steering mechanism and Brake circuits (emergency/ park & service).

Pump circuit includes strainer and breather.

Service Jack Control valve The shuttle car is fitted with four machine

lifting service jacks. The service jacks are operated individually

from a common control bank. The shuttle car must be positioned on a hard

ground before lifting it off the ground. Brakes Following the start up of pump motor, the

wet brakes are released. The wet brakes are mounted on traction

reducer and has internal braking discs. These are spring applied and hydraulically

released

Pressure and flow , provided by low volume are used to release the park/emergency brakes.

The sequence valve assures a constant pressure for the correct operation of park brakes.

When pump motor starts the brake solenoid is energized.

The operators should not leave the compartment without applying park brake.The pressure gauge in operator compartment must read 0 bar.

Consists of controller, an opto(digital I/O Box), electronic overload relay’s, a display unit, Optical drive units and electrical switches.

Digital I/O Box acts as a convertor. All inputs to this box(110v ac) is converted to a 24v dc output, before it passes to controller for circuit operation and diagnosis. Here it acts a protector of controller.

We have Power Supplies (PS1 & PS2): PS1 is connected to Controller, Opti drive units,

Digital I/O Box and display unit.

Electric System

CONTROLLER This is one of the important features of

shuttle car which controls and monitors various machine functions by correlating with the operator inputs from the electrical switches.

Communication and data exchange between the overload relay’s, display unit and central controller are effected by means of a CAN bus communication.

Circuit Breaker The electrical circuits of the shuttle car are

controlled by circuit breakers located in the main controller case. These must be closed before the power supply is given to electrical components.Breaker Function

Machine Main breaker Provides protection for all electrical circuits on the machine

Control and lighting Breaker

Provides protection for the lighting and the control circuits

Traction Breaker Provides protection for both traction Motors.

Optidrives The optidrive system utilizes 3-phase AC

motors for traction control on the shuttle car.

The 2 optidrives supply power at variable voltage and variable frequency, to the traction motors.

The system uses power electronics technique to convert AC to DC(rectifier),smooth the DC (filter) and then to convert DC to AC (inverter)to provide a variable voltage variable frequency(VVVF) output.

Motor rotation is determined by the Integrated Gate Bipolar transistors(IGBT) within the optidrive.

Motor current is sensed by two closed loop hall effect current sensors.

Each optidrive provides thermal overload protection (TOL)for the traction motors.

Display Screens The display unit registers both machine

operation and status information. There are 9 different screens available ,

each will display detailed information to aid in operating and troubleshooting the machine.

Audible Siren The siren sounds when the pump is being

started, which is directly powered from central controller during the pump start cycle.

Switch name location functionFoot switch Near the foot

of operator.Pressed during tramming.

Emergency stop switch

Master stations cover

To stop moving machine instantly.

Pump switch On Master station cover

Shut the machine in emergency & to start pump.

Conveyor switch

Master station Start and stop the convryor

Low cable cut off switch

Cable drum of machine

To open pilot line before cable is completely wound off

Switches

Switch name Location functionOverfill cable cut off switch

Cable reel drum compartment

Open the pilot line when cable reel drum is overfilled

Brake pressure switch

In line with hydraulic brake circuit

Sensing the pressure of hydraulic fluid.

Oil level and temperature switches

Hydraulic tank Check level and temperature of oil respectfully

Consists of Upper & lower steering arms, Drag links, Cross over drag links, steering lever or butterfly and cross shaft.

A steering cylinder is mounted onto each steering lever and when operator operates steering control from his cabin, it pulls and push the steering levers, which turn the wheels to left and right with the help of drag links.

These are found on both the sides of SC, mounted onto the steering cross shaft.

Steering Arrangement

Steering Arrangement

As hydraulic oil is directed into the extend port of the cylinders , the rod will extend rotating the steering lever about the cross shaft.

The draglinks will either push or pull the steering arms attached to wheel units.

This results inwheel units rotating about a kingpin and allowing the operator to steer the shuttle car.

Working of Steering Mechanism

Steering Cylinder The steering cylinders used on

the shuttle cars are double acting.

All shuttle cars are equipped with a dual cylinder arrangement.

The function of them is to convert hydraulic pressure into mechanical force.

It is an integral part of SC, on which the coal is loaded from receiving end and has a width of 0.81m.

It is equipped with conveyor chain having flight bars. Conveyor chain is adjusted for tensioning and to avoid slackness using a conveyor take up shaft.

Conveyor Drive

Conveyor take up shaft Conveyor take up shaft is equipped with

sprockets on both sides on which the conveyor chain sits.

This conveyor take up shaft is connected with a grease jack or take up cylinder.

spacerTake-up

rod

pinsprocket

nut

shims

washer

Take-up nut

Take up

shaft

Grease

jack

Conveyor Drive Motor/Reducer Conveyor is run by conveyor motor of 18.6KW

(AC induction), attached with a conveyor reducer through castle nut, split pin and O-ring. Component WeightConveyor reducer 260 kgConveyor motor 275 kg

1.Reducer2.Motor3&4.Mounting bolts5.castle nut6.Pinion gear7.Key8.O ring9.Nut10.Split pin

The conveyor boom is connected to the car by a pivot shaft.

Below the boom there are 2 conveyor elevating cylinders used to lift up the conveyor.

The weight of these cylinders are 79 kg.

Conveyor Boom

The CABLE REEL MECHANISM is used by the SHUTTLE CAR to wrap the sagging trailing cable into the vehicle.

This prevents the cable from knot formation and tampering.

It maintains a pulling force in the cable and prevents sagging due to the weight of the cable.

Stops the vehicle when cable is exhausted and thus prevents tearing of the cable.

Cable Reel Arrangement

CABLE REEL DRUM

Click icon to add picture

The cable reel drum is powered by a cable reel drive motor through a cam spooler drive chain.

The cable reel drive chain is lubricated with a squirt of hydraulic fluid whenever the cable reel starts rotating.

Cable Reel & Cam Spooler Drive Chain

CAM SPOOLER

THANK

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