The TE 72 Two Roller Machine is for the study of traction, wear and rolling contact fatigue under conditions of pure rolling and rolling and sliding, with dry and lubricated contacts. Two versions of the machine are available covering different load and power capacities.
The principal advantages of the over-hung design are, firstly, that the test rollers are readily accessible and can be removed without removing a bearing and secondly, that such designs allow variable shaft centre distances, thus allowing the maximum flexibility when it comes to the choice of test roller diameters. The principal disadvantage of the over-hung design, when compared with the fully supported design, is that the arrangement produces a cantilevered load on the test spindle bearings, thus limiting the maximum load capacity of the machine, compared with that achievable with the latter arrangement.
The TE 72 Two Roller Machine comprises two a.c. vector motors, each connected by timing pulley to a test assembly. One drive incorporates an in-line torque transducer, which is connected via a cardan shaft to a roller spindle, mounted in turn on a radially oriented, linear slide. The cardan shaft and slide permit horizontal displacement of the roller spindle, allowing load application and adjustment for different diameter rollers. The spindle assembly includes an alignment mechanism that allows the spindle to be rotated in a vertical horizontal plane about the point of contact, allowing introduction or removal of small amounts of skew.
The second roller spindle is mounted on an axially oriented linear slide, which allows axial displacement of one roller relative to the other. The slide is mounted on a bracket, which is, in turn, mounted on the machine base plate, through a pivot. This allows adjustment for line contact alignment of the rollers. The roller spindle is connected through a telescopic cardan shaft to a lay-shaft and thence via belt drive to the second motor. Application of axial movement on the roller contact, when in motion, allows investigation of the effects of lateral movement on traction coefficient.
Removal of this assembly and replacement with an optional holder for mounting block samples allows the machine to be used for performing block-on-ring experiments. This involved rotating the axial slide through 90 degrees into the vertical plane. The addition of a servo motor and drive to the slide allows reciprocating block on ring tests to be performed in the configuration sometimes referred to as a “reciprocating Amsler” test.
It will be noted that the use of an in-line torque transducer for traction measurement is subject to parasitic losses associated with the roller spindle bearings. These losses a very small but may be quantified by running the unit under conditions of zero slip at different speeds and temperatures. The roller spindles, which are oil fed, are sealed with labyrinths, thus eliminating parasitic losses associated with conventional sliding seals.
Load is applied by means of a servo controlled pneumatic bellows with force transducer feedback. The motors are a.c. and powered by conventional vector drives allowing precise control of speed. Power is re-circulated electrically via a common d.c. link between the drives, upstream of the frequency inverter stages. Total power requirement is thus limited to the system losses. For control purposes, one drive is designated as master with the second drive deriving its speed set point, adjusted for the required slip ratio, from the master drive.
A vibration sensor is provided for detecting surface fatigue failure. One roller housing is electrical isolated and both spindles are provided with brushes for electrical contact potential measurement.
Test may be run either dry or jet lubricated. A test fluid service module is fitted as standard incorporating a sump tank with immersion heater, delivery pump and oil to water heat exchangers for cooling.
Control and Data Acquisition
The TE 72 has PC based sequence programmable control and data acquisition. This is provided by an integrated Serial Link Interface Module and COMPEND 2000 software running on a host PC, operating under Windows. Data is stored to hard disc in standard spread sheet compatible file formats (.csv or .tsv).
Tests are defined by a sequence of steps, each step containing set-point, data recording rates and alarm level information. Set-points may be adjusted by step change or ramp. The test sequence is followed unless interrupted by the operator or an alarm. Set-points may also be adjusted manually using on screen toggles.
Technical Specifications – TE 72S
Type: Circulating power Overhung roller Spindles opposed Variable shaft centre distance Contact: Line or point contact Test Conditions: Pure Rolling Sliding/Rolling Environment: Dry & Lubricated Maximum Roller Diameter: 120 mm Minimum Roller Diamater: 50 mm Maximum Shaft Centre Distance: 120 mm Minimum Shaft Centre Distance: 50 m Maximum Roller Thickness: 30 mm Maximum Load: 5 kN Slide-Roll Ratio: 0 – 200 % (pure rolling to pure sliding) Roller Temperature: Ambient to 150°C Maximum Roller Speed: 3000 rpm Maximum Motor Power: 4 kW @ 1500 rpm Maximum Motor Speed: 3000 rpm Maximum Roller Spindle Speed: 3000 rpm Base Speed: 1500 rpm Drive Ratios: 2:1, 1:1, 1:2, 1:3 Maximum Torque 2:1 Belt Ratio: 12.5 Nm @ 3000 rpm Maximum Torque 1:1 Belt Ratio: 25 Nm @ 1500 rpm Maximum Torque 1:2 Belt Ratio: 50 Nm @ 750 rpm Maximum Torque 1:3 Belt Ratio: 75 Nm @ 500 rpm Maximum Axial Travel: 20 mm Block on Ring: Optional Test Conditions: Sliding Maximum Load: 1000 N Maximum Reciprocating Speed: 1 mms-1 Maximum Linear Travel: 30 mm Controlled Parameters Motor speed Motor speed difference Applied load Test fluid temperature Test duration Measured Parameters Motor speed Motor speed difference Applied load Transmitted torque Electrical Contact Resistance Lubricant inlet temperature Test bath outlet temperature Vibration sensor output Services Electricity: 380/415V, three phase plus neutral, 50/60 Hz, 10 kW Clean, dry air: 4 cfm at 8 bar (120 psi) Mains water and drain: 10 l/min (typical)
Technical Specifications – TE 72H
Type: Circulating power Overhung roller Spindles opposed Variable shaft centre distance Contact: Line or point contact Test Conditions: Pure Rolling Sliding/Rolling Environment: Dry & Lubricated Standard Roller Diameter: 150 mm on 150 mm Maximum Shaft Centre Distance: 155 mm Minimum Shaft Centre Distance: 105 mm Maximum Roller Thickness: 30 mm Maximum Load: 21 kN Continuously Variable Slide-Roll: 0 to 3000 rpm Slide-Roll Ratio: 0 – 200 % (pure rolling to pure sliding) Roller Temperature: Ambient to 150°C Maximum Motor Power: 30 kW @ 1500 rpm Motor Base Speed: 1500 rpm Maximum Motor Speed: 3000 rpm Maximum Spindle Speed: 6000 rpm Drive Ratio: 1:1 Maximum Torque at 1500 rpm: 190 Nm Maximum Torque at 3000 rpm: 95 Nm Maximum Surface Speed (150 mm Roller): 11 ms-1 Drive Ratio: 2:1 Maximum Torque at 1500 rpm: 95 Nm Maximum Torque at 3000 rpm: 47.5 Nm Maximum Surface Speed (150 mm Roller): 22 ms-1 Maximum Axial Travel: Nil Controlled Parameters Motor speed Motor speed difference Applied load Test fluid temperature Test duration Measured Parameters Motor speed Motor speed difference Applied load Transmitted torque Electrical Contact Resistance Lubricant inlet temperature Test bath outlet temperature Vibration sensor output Services Electricity: 380/415V, three phase plus neutral, 50/60 Hz, 75 kW Clean, dry air: 4 cfm at 8 bar (120 psi) Mains water and drain: 10 l/min (typical)
LB Foster Rail Technologies Canada Tsinghua University China Arcelormittal Maizieres France Tonen Japan Tata Steel UK
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