Wheel Balancing System

System Introduction

Wheel Balancing system is a kind of device used to measure the unbalance value and location of rotational object (rotor). When rotor rotates around its axes, as the weight to the axes distributes asymmetrically, it produces centrifugal force. This kind of unbalance centrifugal force will cause rotor and axes vibration, generate noise and aggravate the abrasion of axletree, which severely affects the performance and lifespan of the product. Balancing machine corrects the unbalance value of the rotor according to the measured data. It improves the weight of rotor distribution to the axes, so as to keep the vibration of the rotor and vibration force caused to the axletree in an allowed range. Therefore, balancing machine is an essential device for reducing vibration, improving performance and quality.

As train travels faster and faster, it demands high-grade railways. Wheel is an important part of the train. The accumulation of wheel unbalance magnitude is one of key factors determined train vibration. The reasons of severe vibration of train includes: wheelset balance value, eccentricity and the diameter difference of the same pair of wheels exceed the limit. The diameter difference of the same pair of wheels and eccentricity must be strictly controlled in the allowed range, and dynamic balance value should be not beyond 50g/m. The severe vibration of vehicle in high speed may cause that oil pressure damper leaks oil, the spring of axle box breaks and so on, and deteriorate the quality of running railway vehicles.

System Characteristics

1) Easy to operate. The automatic measurement of balance is combined with NC cutting system, automatically transfering dynamic balance measurement value into cutting movement track.
2) High precision and reliability. Automatically protect equipment and milling cutter from accidentally power-off or milling aging.
3) Adopt pneumatic control technology to control train wheelset.
4) Display on one screen, automatically print and save.
5) Solve the problem that for traditional four-wheel drive, the uneven of wheel tread leads to the error of dynamic balance measuring result. We make use of the center of shaft: three bolt holes plus high strength software protection, guaranteeing a certain drive force but not damaging bolt holes. It has a long life span and needn't replace frequently.
6) The principal axis automatically aligns and connects. Measure after setting apart at a high speed, i.e. thoroughly lighten two balances, once deweight. While cutting, it independently bears rotor, hydraulic oil axletree and scrap iron plate, featuring complete recycling scrap iron, high precision de-weight, etc.

System Principle

The system is divided into two parts: balance measurement and wheelset processing. They are both controlled by one Industrial PC. Based on the same base, the train wheelset is controlled through pneumatic control technology to complete the whole process from ascending, descending to pushing out.

Balance measurement system comprises rotational velocity transducer, vibration transducer, oil pressure supporting device, bracket, spindle motor, spindle split device, measurement computer cards as well as associated measuring program. Wheel is fixed to bracket through pneumatic control feed device. Oil pressure device starts supplying hydraulic oil to support wheel. Stepping motor drives the main shaft coupling to connect wheel, spindle motor drives wheel to rotate. After reaching a certain rotating speed, the main shaft coupling is apart from wheel and conducts dynamic unbalance measurement. After measurement complete, assist brake device to stop the rotation of wheel. Measure unbalance magnitude and perform wheelset processing.

Wheelset processing mainly focuses on the milling process of wheel. Remove the accumulation of wheel to achieve balance. Wheel processing system consists of milling cutter locating unit, milling cutter rotation unit, cutting locating unit, cutting supporting unit and wheel rotation unit. If unbalance value is found, it enters milling process. Through locating unit, computer positions the place and starts cutting, at the same time milling cutter enters into the internal side of the wheel and cuts. Stepping motor drives wheel to rotate anti-clockwise. At this time, the rotational direction of cutting miller is opposite to the wheel rotational direction, cutting the internal side of the wheel. In general, it processes at 90°~120° arc angle.

Block Diagram

System Configurations

Chassis: IPC-810A/6114P4A/7271AT
Motherboard: FSC-1717VN
Configuration: Pentium4 /2G / 160G SATA
I/O Card: PCI-16P16R
PCI-16P16R: 16-bit relay output controls cutting motor start/stop, step motor start/stop, principal axis motor start/stop; 16-bit digital input acquiring control on-off signal

System Evaluation

The dynamic balance NC correcting system of Train wheelset combines dynamic balance measurement and wheel-pair processing. It has the virtues of high precision processing, low stress concentration after cutting, high automation level, high production efficiency and so on.