Discussion on reliability index of locomotive and rolling stock

Through the discussion of the reliability index of rolling stock, it is proposed that MDBF, MDBFF and online rate can be used as products of rolling stock manufacturing enterprises.

The proposal of reliability index lays a foundation for manufacturing enterprises to further meet the needs of users and carry out product reliability research.

Keywords: rolling stock; Reliability index; Mean time between failure; Average distance between functional failures; Basic reliability; Mission reliability

Introduction to 0

With the rapid development of China's national economy, transportation and logistics are developing day by day.

Increase. Railway transportation accounts for 70% of the total freight and passenger traffic in China.

60%。 As the equipment of railway transportation-the running safety of locomotive and rolling stock

Punctuality is one of the key factors to ensure railway transportation. So we need a motorcycle.

The vehicle has high reliability. The latest international railway industry standard IRIS

But also clearly put forward RAMS (reliability, availability, maintainability and

Safety) requirements. Therefore, it is railway equipment to improve the reliability of products.

Key factors for manufacturing enterprises to participate in international competition. Because of the country's concern for locomotives and rolling stock

The research on the reliability of a vehicle is still in its infancy, and it can only be participated in at present.

According to the reliability standards of other systems, based on experience and general statistical data.

The reliability requirements are put forward, and the mature reliability index and acceptance have not been established yet.

The system makes the reliability management of rolling stock unsatisfactory. So do it.

Study the reliability requirements of rolling stock and establish scientific and standardized rolling stock.

Reliability index and acceptance system are of far-reaching significance to locomotive and rolling stock manufacturing enterprises.

Meaning of.

Because the reliability index and verification method of the whole locomotive and rolling stock are extremely

Complex, this paper only discusses the establishment of its reliability index, and puts forward the construction.

Discuss it.

1 Status of reliability index of rolling stock

At present, as can be seen from the technical documents of rolling stock, it involves

Reliability indicators are basically machine failure rate, imminent repair rate and bad repair rate. In that way

However, in the specific use of machine damage rate, temporary repair rate and bad repair rate to assess locomotives and vehicles.

There will be some problems in the reliability of the whole vehicle.

According to the definition of IEC60050( 19 1), reliability is "the product is specified.

Condition, and complete the specified function within the specified time interval (t 1, t)2.

Force ",its quantitative index-reliability, is" the product is in the prescribed article.

The probability of completing the specified function within the specified time. "Therefore, the real.

To discuss reliability internationally is to discuss failure probability. The failure rate of rolling stock is

Divide the total mileage of locomotives and vehicles in use by t=0 to the time.

T=t 1, the ratio obtained by accumulating the number of machine failures. Temporary repair of railway vehicles

Rate, that is, divided by the total running kilometers of locomotives and vehicles in use from t=0 to t = 0.

Time t=t 1, cumulative number of locomotive failures without maintenance.

The ratio of. The repair rate of rolling stock is based on the total mileage of rolling stock in use.

From time t=0 to time t=t 1 divided by the cumulative number of locomotives, it will not be put into storage unless it is repaired.

The ratio of the number of faults repaired. This is the cumulative failure probability.

Rate (F()t).

First of all, due to this cumulative failure probability, all in-use should be evaluated.

Specific types of locomotives and vehicles, and then the mileage of locomotives and vehicles in use.

This number has a great influence on the cumulative failure probability. The more miles,

The smaller the cumulative failure probability. At the same time, due to the investment of each locomotive (batch)

According to the principle of product failure bathtub curve, it appears at different times.

Fault types and probabilities are different. We count all the data at a specific time.

With the use of rolling stock, the types and probabilities of faults may deviate.

Secondly, reliability can be divided into inherent reliability and operational reliability, and can also be divided into

Basic reliability and mission reliability. Keywords machine breakage rate, temporary repair rate, bad repair rate,

Is the evaluation of inherent reliability, basic reliability or reliable use?

Sex and mission reliability must be explained, otherwise it is easy to produce reliability.

Different understanding, thus adopting different reliability assurance schemes.

Third, the statistics of machine failure rate, which leads to any train being delayed for 5 minutes (to

For example, the equipment failure of Beijing-Guangzhou line is a machine failure. However, in practice.

When the equipment breaks down, there are many factors that affect the train delay, among which

It is not only related to the fault type and the maintainability of the system, but also related to the driver and passengers.

The technical level is closely related to the redundancy of product design. Such as: locomotive running

On the way, the main grounding fault occurred in the silicon unit due to capacitor breakdown, and the driver and passengers were isolated.

Some motors kept running and arrived on time, which did not cause damage to the machine, but actually did.

Product failure; Sometimes, it may be because the training is not in place, and the driver and passengers are right.

The product is unfamiliar and may be improperly operated, resulting in the train being delayed and the machine being broken, but the product itself is not broken.

As can be seen from the above analysis, the failure rate, temporary repair rate and bad repair rate are all difficult.

Truly and comprehensively reflect the reliability of products, which will promote manufacturing enterprises to improve production.

The role of product reliability is limited. Therefore, it is necessary to study the feasibility of rolling stock.

Use sex index to study and discuss.

2 Reliability index of rolling stock

Both the International Electrotechnical Commission (IEC) and the European Standard (EN) aim at the orbit.

The Ministry of Communications has formulated the reliability requirements, namely IEC 62278, EN 50 126 and EN.

50 128, EN 50 129, etc. But these standards only give the applicability of rail transit.

The examples of typical parameters of reliability have no practical guiding significance. through

After comparing the relevant IEEE standards with the actual operating experience of rolling stock, we are considering

It is suggested that the average functional fault room should be used when the reliability index of rolling stock is complete.

Average distance between functional failures,

MDBFF), mean fault spacing (mean fault spacing-

Ure, MDBF) and online service rate of rolling stock.

Three indexes to comprehensively measure the reliability of rolling stock.

As a characteristic quantity of basic reliability of rolling stock, MDBF can

Reflect the influence of vehicle operation on maintenance personnel, maintenance time, maintenance cost and equipment.

Requirements for spare parts. The basic reliability of a system is low, even if it is full

The requirement of mission reliability will also lead to high system maintenance costs. in other words

Through the guarantee of equipment redundancy, although the task reliability can be met, but later

The maintenance cost can not be ignored, and the resulting system is complex.

With the increase of the degree, the basic reliability of the system will also decrease.

Based on the quality index established by international rail transit equipment manufacturing enterprises

Look, MDBF has six indicators to measure. Details are as follows:

1) Zero-kilometer fault: the product has reached the stage where it has not been officially put into use.

Current fault.

2) Early failure: the product is put into use to the specified shortest repair stage.

The fault that happened.

3) Operation failure: The product fails in normal operation, but it can be delivered.

Destination.

4) Unplanned maintenance: incoming inspection will not be conducted during the scheduled maintenance time.

Repair and maintenance without storage.

5) Shutdown failure: the product stops suddenly during operation, but it is reconnected or connected.

The reason for hanging can be dragged to the destination.

6) Task failure: the product failed to run and could not reach the destination.

As a characteristic quantity of railway vehicle mission reliability, MDBFF can

To reflect that the whole vehicle has completed the specified work within the specified time period or task period.

The ability to do sth. This characteristic quantity is similar to our current general machine breakage rate.

, but the dimensions are different. As a manufacturing enterprise, in order to ensure the task of the whole vehicle

Reliable, certain equipment redundancy must be considered in vehicle design, and at the same time

The simplification of the system of giving consideration to both is a contradiction.

MDBF and mdbf reflect the reliability index of rolling stock.

Can not reflect the quality of vehicles in the process of undertaking transportation tasks.

The quality state of the vehicle when it does not undertake the transportation task. Sometimes, running online.

The quality of rolling stock is in good condition and trouble-free, but it is on standby.

The quality of rolling stock is not good, and it can't even be put into operation. although

MDBF and mdbf can meet the requirements, but the standby machine

The vehicle quality can't meet the user's requirements. Therefore, international iron

The highway industry has introduced the online rate index. Definition of on-line speed of railway vehicles

It is the sum of the number of locomotives and rolling stock running online and the number of good standby locomotives and rolling stock.

Divided by the total number of rolling stock. The online rate index objectively reflects the manufacturing enterprises.

The service quality, maintainability and availability level of products also affect the use of products.

The reliability of home transportation is one of the focuses that users pay attention to at present. Therefore, the machine

The on-line rate of vehicles should also be used as an indicator of reliability.

To sum up, MDBF can be measured as a basic reliability index.

Maintenance personnel, maintenance time, maintenance cost and spare parts of the whole locomotive and rolling stock.

The requirements of demand. Taking MDBFF as the mission reliability index, the measuring machine

The ability of the vehicle to complete the specified function. The online rate of the whole vehicle is reliable.

Related indicators of sex.

3 calculation of MDBF and mdbf

Because rolling stock is a large electromechanical product, it is impossible to simply electronic zero.

Components or mechanical parts for measuring reliability data. Although the parts themselves

There are not many types of failure modes, but they should be considered after becoming the whole product.

There are many factors, such as the failure mode combination of various parts, which are determined by the following factors.

Failure caused by combination of parts (non-part failure).

Composition of patterns. Therefore, from the whole machine, a large number of approximate functions have been formed.

Close, its form becomes complicated.

In actual measurement, Weibull probability paper can be used to measure the failure probability.

The slope of the line is used to obtain the shape parameter m to determine the nature of the fault (m= 1,

Unexpected failure; M> 1.

The failure rate λs is estimated by exponential distribution, and every unit of the system has service.

According to the exponential distribution, the unit reliability R(i)t=e-λit.

System reliability r (st) = e-λ1te-λ 2te-λ 3t ... e-λ nt = e-λ st.

System failure rate λs=λi

Mean time between failures MTBF= 1/λs

Considering that the failure of rolling stock is traditionally carried out according to the number of running kilometers.

Statistics, combined with locomotives and vehicles in the standby period of mean time between failure.

Will have an impact, so it is recommended to use mean time between failure.

(MDBF) to replace the mean time between failure of reliability budget estimation.

However, you need to count1/λ s.

Take a three-locomotive fault system of a certain model in a certain year 10 as an example.

Meter, to measure the MDBF and mdbf of automobile, we can see that it is related to machine failure.

See table 1 and table 2 for the differences of temporary repairs. The surge current in the On, RC circuit is too large (the maximum working capacity of the capacitor

2.55 times the current), thus accelerating the aging, degradation or damage of the capacitor. electric current

The power of the resistor is 1.55 times of the maximum working power, which cannot meet the requirements of the resistor.

Make a request.

2) Use the modified parameters (R = 12.4ω, C= 18μF) in the rectifier bridge.

When the thyristor is turned on, the peak value of the capacitor discharge current only changes.

The power of the resistor is the pre-reconstruction value of 1/3, and the power of the resistor is also lower than the pre-reconstruction parameter value.

About100 W. When the thyristor is turned off, the peak value of the capacitor discharge current changes.

1/2 before construction, the working conditions of rectifier components were improved.

3) After modification, when the rectifier bridge is turned on at 90, the limit work of the capacitor will be reduced.

The current value is only 1.2 times of the maximum working current, and the resistance works at the limit.

The power is 65438+ 0.4 times of the maximum working power. Considering the 90 commutation of the rectifier bridge

For instantaneous heating, the resistor has a certain heat dissipation time, which may burn out the resistor.

Less energy.

4 conclusion

At the end of 2007, Xinxiang Locomotive Depot and Zhungeer Locomotive Depot shall be implemented according to the above methods.

Five modified SS4 locomotives have been tested in the transformation scheme, but they have not been put into operation so far.

The problems of RC loop resistance and capacitor burning and breakdown appear again. Explain the transformation.

This scheme can solve the problems of resistance breakdown and capacitor burning in RC circuit of SS4 improved locomotive.

Fault. Moreover, the transformation scheme is simple and the transformation cost is low, which is suitable for other SS4.

The modified locomotives were modified in batches.

References:

[1] Zhang Yousong, Zhu Longju. Shaoshan type 4 electric locomotive [M]. Beijing: China Railway Press,

[2]200 1.

[2] Jiang Jiajiu. Influence of Parameter Matching of Traction Winding Damping Circuit of Electric Locomotive on Equipment Safety

[2][J]。 Railway Vehicles, 2005(4).