Some standard content:
JB/T51022-1999
This standard is a revision of JB/T51022-92 "Product Reliability Assessment Method for Front-end Grass Machines". Compared with JB/T51022-92, the main technical content of this standard has been changed as follows: Appendix A has been changed to the standard-promoted appendix;
All record forms have been removed.
This standard replaces JB/T51022-92 from the date of implementation. Appendix A of this standard is the appendix of the standard. This standard was proposed and managed by Hohhot Animal Husbandry Machinery Research Institute. The drafting unit of this standard: Hohhot Animal Husbandry Machinery Research Institute. The main drafters of this standard: Hai Yurong, Dorji, Gao Lijun. 272
1 Scope
Machinery Industry Standard of the People's Republic of China
Reliability Assessment of Turf Blowers
(Internal Use)
JB/T 51022-1999
Replaces JB/T51022--92
This standard specifies the fault classification, judgment rules, test methods and evaluation rules of disc and cylinder turf blowers (hereinafter referred to as turf blowers).
This standard is applicable to the reliability test of mass-produced turf blowers. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB7681-1997 Safety Technical Requirements for Lawn Movers
JB/T9707.1—1999 Technical Conditions for Lawn Movers JB/T9707.2—1999
3 Definitions
Test Methods for Lawn Movers
This standard adopts the following definitions.
3.1 Intrinsic Failure
Under the specified conditions of use, the failure caused by the inherent defects of the product itself is called an intrinsic failure. For example; excessive deformation, fracture, failure, and excessive performance degradation of parts.
3.2 Dependent Failure
The derived failure caused by the intrinsic failure is called a dependent failure. For example: the fracture of the engine connecting rod bolt is an essential failure, and the damage to other parts caused by it is a dependent failure.
3.3 Misuse Failure
The failure caused by the user's illegal operation and use is called a misuse failure. 3.4 Lawn mower failure
Any phenomenon in which a lawn mower (or its parts) cannot complete its specified function (or its performance degrades beyond the specified range) when used under specified conditions is a lawn mower failure.
3.5 Associated failure
Human failure must be taken into account when calculating the numerical value of reliability characteristic quantity or interpreting test results. 3.61 Unassociated failure
Human failure is not taken into account when calculating the numerical value of reliability characteristic quantity or interpreting test results. 3.7 Independent failure
The fault location is the essential failure of the source of the failure. 3.8 Point estimate
A point estimate is a single value used to represent the unknown true value of a statistical parameter. The point estimate generally refers to the average of the observed values. Approved by the State Bureau of Machinery Industry on December 30, 1999 and implemented on June 1, 2000
3.9 Confidence interval estimate
JB/T51022—1999
Use an interval to determine the range to which an estimate belongs, which includes the true value of the estimated parameter with a certain probability. It can be bilateral or unilateral.
3.10 Confidence level
The probability of including the true value of the estimated parameter, also known as confidence level. Fault classification and weighting
4.1 Fault classification
4.1.1 According to whether humans are included when calculating the numerical value of reliability characteristic quantity or interpreting test results, faults can be divided into two categories: associated faults and non-associated faults.
4. 1. 1. 1
Associated faults include:
a) independent faults;
b) wearing parts are replaced before the replacement cycle. 4.1.1.2 Non-related faults should include:
a) misuse faults;
b) subordinate faults.
4.1.2 According to the classification of fault modes, there are mainly: a) functional failure caused by excessive deformation, breakage, early wear, and jamming of parts; b) performance indicators drop below the specified range; c) adjustment failure;
d) fastening failure.
4.1.3 In order to comprehensively evaluate the failure of the mower, the related faults are divided into the following four categories according to the severity of the consequences of the fault, the degree of impact on the function of the mower, and the difficulty of troubleshooting. 4.1.3.1 Fatal fault
Faults that endanger personal safety, cause personal injury or death or the scrapping of the mower, and cause major economic losses. 4.1.3.2 Serious faults
Faults caused by damage to major components and large economic losses, which cannot be eliminated in a short time using random spare parts and common tools. 4.1.3.3 General fault
Minor parts are damaged, performance parameters drop below the specified value, the economic loss caused by the fault is small, and the fault can be eliminated in a short time with the random spare parts and common tools.
4.1.3.4 Minor fault
Fault that does not affect normal operation temporarily, does not require replacement of parts, and can be easily eliminated with common tools. 4.2 Fault weighting
In order to evaluate the consequences of failures and calculate the comprehensive reliability score, each type of failure should be weighted, and the hazard coefficient of each type of failure is as follows: a) Minor fault: K; = 1
b) General fault: K, = 5
c) Serious fault: K: -25
5 Fault judgment rules
5.1 When judging the category of a certain fault, the final consequences of the fault should be used as the basis. 5.2 All related faults should be classified according to the examples listed in Appendix A (Appendix to the standard). For the failure modes not listed in Appendix A, the category shall be determined according to the specific situation and with reference to the examples in Appendix A. 5.3 A related failure shall be determined as a failure frequency and can only be determined as one of the four categories. When calculating the characteristic value, only related failures shall be counted and non-related failures shall not be counted. All the failures that occur shall be recorded in detail. 5.4 For multiple failures that occur at the same time, if these failures occur independently, each failure shall be counted as a related failure separately; if one of the failures is the only cause of other failures, only one related failure shall be counted, and its failure category shall be determined according to the final consequences caused by the failure.
5.5 Minor failures that occur during the test shall only be counted when calculating the comprehensive reliability score, and shall not be included in the calculation of the single index value of the reliability of the mower.
5.6 When the performance parameters of the mower drop to the following requirements, it shall be judged as a failure, and each item shall be recorded as a failure frequency. a) During the initial performance test, if the kilowatt-hour output per unit grass length is less than 30kg/(kW·h·mm); the load level is less than 80% or greater than 110%; and the blade sharpening cycle is less than 6h, it should be judged as a general fault. The fault time is calculated as zero hours (the blade failure time is calculated according to the actual working time);
b) During the performance retest, if the kilowatt-hour output per unit grass length is less than 26kg/(kW·h·mm); the load level is less than 80% or greater than 110%; and the blade sharpening cycle is less than 4.8h, it should be judged as a general fault. The failure time is calculated according to the test cut-off time. 5.7 Before the test begins, the inspection items specified in Chapter 8 should be inspected in accordance with the provisions of the relevant product standards. If they do not meet the requirements, they will be counted as faults and the failure time will be counted as zero hours. 6 Failure mode
For details of the failure mode, please refer to Appendix A.
7 Fault repair
7.1 Maintenance
Adjustment and regular maintenance of the mower according to the instructions for use shall not be counted as a fault. The time required for adjustment and maintenance shall be included in the maintenance time.
7.2 Principles for replacement of wearing parts
Replacement of wearing parts that have reached the specified life is allowed during the test, and such replacement shall not be counted as a fault, but detailed records shall be made of the replaced parts and the time required for replacement. 7.3 Maintenance conditions
7.3.1 Maintenance conditions refer to the operator's comprehensive ability to diagnose faults, maintenance technical level, spare parts supply conditions and management level;
7.3.2 In order to control the impact of maintenance conditions on maintenance time and test results, the following provisions are made: a) Record in detail the operator's education level, technical level and the time the user has used the mower. b) Repair time only records direct repair time: Direct repair time refers to the time from forced shutdown due to a fault to restoration of function, which includes fault diagnosis, troubleshooting and adjustment test run time. The time wasted waiting for spare parts and maintenance preparation is not included. c) When the fault is not eliminated due to misdiagnosis and needs to be repaired again, only the time of re-diagnosis and repair is counted as the repair time. 8 Test method
8.1 Test Samples
8.1.1 Test samples shall be randomly selected from products produced in batches and qualified by the inspection department of the manufacturer. 8.1.2 Product batches and sampling numbers shall comply with the provisions of Table 1. Table 1 Sampling Table
Annual Output
Batch N
Sampling Number
Number of Test Samples
8.2 Test Conditions
JB/T 51022-1999
8.2.1 When measuring the unit grass length kilowatt-hour output and load level, the test material shall be cereal straw, and the moisture content shall not be higher than 17%. In other cases, this restriction may not apply.
8.2.2 The working voltage of the motor, the accuracy of the test instruments and meters, and the accuracy of the measured values shall comply with the relevant provisions of JB/T9707.2. 8.3 Test procedures and methods
8.3.1 Safety design inspection
Inspect the product item by item according to the provisions of Chapters 3, 4 and 5 of GB7681. If it does not meet the requirements, it will be recorded as a fault. The fault time is calculated as zero hours.
8.3.2 Adjustment and test run
Adjust and test run the prototype according to the provisions of the instruction manual, and inspect it according to the provisions of 8.2 of JB/T9707.1--1999. If it does not meet the requirements, it will be recorded as a fault, and the fault time is calculated as zero hours. 8.3.3 Initial performance test
At the beginning of the test, measure the unit grass length kilowatt-hour output, load level and blade sharpening cycle according to the provisions of JB/T9707.2. The fault judgment criterion is the provisions of 5.6a).
8.3.4 Reliability test
8.3.4.1 The reliability test adopts a replacement timed truncation test scheme, and the test time for each prototype is 100 hours. 8.3.4.2 The prototype should be tested under actual use conditions. During the test, the prototype should be used and maintained in accordance with the provisions of the instruction manual.
8.3.4.3 During the test, the shift time should be recorded every day. 8.3.4.4 During the test, the operation and operation quality of the prototype should be observed frequently. If the following situations occur, the test should be stopped immediately and the test can be resumed only after the cause is found and the fault is eliminated: a) The main performance indicators are reduced;
b) There are abnormal sounds from the moving parts;
c) Parts are damaged, excessively deformed, prematurely worn out, or other failures that cannot complete the specified functions. 8.3.4.5 Faults that occur during the test should be classified according to the provisions of Appendix A. Carefully find the faulty part, analyze the cause of the fault, and take photos or perform physical and chemical analysis on the faulty part or failed parts when necessary. 8.3.5 Performance retest
8.3.5.1 When the calculated pure working time reaches the specified cut-off time, the main performance indicators of each prototype shall be retested. The retest items include blade sharpening cycle, unit grass length kilowatt-hour output, and load level. 8.3.5.2 Before retesting, the prototype may be adjusted and maintained according to the provisions of the instruction manual. When measuring the unit grass length kilowatt-hour output and load level, the pure working time of the blade from the last sharpening time to the start of the measurement shall not be less than 2.4h. 8.3.5.3 If the measured value exceeds the range specified in 5.6b), it shall be recorded as a fault. 8.3.6 Disassembly inspection
After the test, the prototype shall be fully inspected (disassembled for inspection if necessary) to find out all the faults that have not been recorded. The fault time is calculated based on the accumulated pure working time of each prototype. 8.3.7 Data statistics
After the test is completed, the test data should be counted and summarized in a timely manner, and the reliability index value should be calculated. 9 Evaluation rules
9.1 Symbols and meanings
6——Target value of mean time between failures MTBF of high-quality products in the lawn mower industry (for lawn mower products, 8=200h), —Point estimate of MTBF;
---Lower limit of one-sided confidence interval of MTBF: 276
x(p,y)-
JB/T 51022—1999
Theoretical value of β quantile of ×2 distribution with degrees of freedom; Total test time of reliability test determined by the test plan; -Number of test samples of reliability test,
t-Test truncation time of a single sample determined by the test plan; -Number of related failures occurring in n samples in a reliability test (excluding minor failures); MTBF—mean time between failures;
Average working time before first failure;
-Comprehensive score of fault-freeness;
1 α—confidence level.
9.2 Reliability evaluation indicators and evaluation methods
9.2.1 Evaluation indicator system
9.2.1.1 The indicator system for evaluating the reliability level of lawn mower products should generally include the following indicators: a) MTTFF
b) MTBF
Among them, MTBF and MTTFF are indicators that must be evaluated. 9.2.1.2 The various reliability indicators specified in this standard may be increased or decreased according to different evaluation purposes. 9.2.2 Calculation method of reliability indicators
a) MTTFF is calculated according to formula (1):
Where: n—
The number of units that have first failure (excluding minor failures) in a sample machine; t—The cumulative working time when the i-th sample machine has the first failure (excluding minor failures), h. —-At the end of the test, among the prototypes that have not had the first failure (excluding minor failures), the cumulative working time of the prototype, h. b) MTBF is calculated according to formula (2) and formula (3):
e=nt/r
xa,2+2)
c) Q is calculated according to formula (4) and formula (5):
Q = 100-
In the formula: K, - the hazard factor of the ith failure (including minor failures); E, - the failure occurrence time coefficient of the ith failure (including minor failures); ro
- the total number of related failures (including minor failures) that occurred during the test; - the cumulative working time when the ith failure (including minor failures) occurs, h. ti
9.2.3 Evaluation rules
(1)
(2)
(3)
·(4)
·(5)
9.2.3.1 If no failure (excluding minor failures) occurs in any of the tested lawn mower products at the end of the test, the product meets the reliability requirements. 9.2.3.2 During the test, if any of the tested lawn mower products has a fatal failure, the test should be terminated immediately and the entire batch of products should be judged as unqualified.
9.2.3.3. When the test is terminated, if no fatal failure occurs to the test machine, the following rules shall be applied: MTTFF shall not be less than 120h, MTBF shall not be less than 180h; Q shall not be less than 65min.
JB/T 51022—1999
a) When evaluating the reliability of lawn mower products, if the tested lawn mower products can meet the first two conditions at the same time, the product batch is judged to be qualified; otherwise, it shall be judged to be unqualified; b) When the reliability of the product is evaluated for other specific purposes, the evaluation rules shall be formulated separately according to the purpose of the test. 10. Reliability Evaluation Report
After the reliability evaluation is completed, an evaluation report shall be prepared according to the following contents: a) Test overview: clarify the test purpose, requirements, test start and end time, test location, test product manufacturer, units participating in the test, etc. ;
b) Introduction to the tested product: introduce the structure, working principle and main technical features of the product; c) Test conditions and analysis: briefly describe the test conditions and analyze their influence on the test results; d) Test results and analysis: summarize the test data and information, comprehensively review the test results, and comprehensively analyze and evaluate the reliability level of the tested product;
e) Based on the analysis of the test results, make a clear review conclusion on the tested product; f) Measures to be taken to improve product reliability; g) Annex: charts, special reports, photos and fault analysis reports on relevant test data. 278
JB/T51022—1999
Appendix A
(Appendix to the standard)
Failure mode and failure classification of leather machine
Failure mode and failure classification of grass machine See Table A1. Table A1
Fault location
Wheel (cutter head)
Electric motor
Moving and fixed cutter fasteners
Bevel gear
Cylindrical gear
Double gear
Transmission shaft
Feeding manifold
Bevel gear
Fault mode
Severe bending
Failure of solidification
Crack or fracture
Deformation, open welding (crack)
Bending, fracture
None or inconsistent with size
Crack or fracture
Serious early wear on tooth surface
Fault cause and situation
Manufacturing and installation quality do not meet the requirements
Manufacturing and installation quality do not meet the requirements
Poor manufacturing quality
a) Bolt performance grade is lower than 8. Grade 8, the nut is lower than Grade 8 and there is no reliable anti-loosening device;
b) Poor manufacturing quality;
c) Too much impact and vibration,
d) Does not reach the specified preload
a) Poor manufacturing quality;
b) The material does not meet the requirements;
c) Improper installation and adjustmentwww.bzxz.net
a) Poor design and manufacturing quality, fatigue fracture;b) Improper adjustment and installation
a) Poor design and manufacturing quality, fatigue fracture;b) Improper adjustment and installation
||a) Poor design and manufacturing quality, fatigue fracture; b) Improper adjustment and installation
a) Poor welding quality, insufficient strength;
b) Too much vibration of the machine base
Manufacturing and installation do not meet the requirements
8) Manufacturing and assembly do not meet the requirements,
b) Poor lubrication, overload operation
Unreasonable design
a) Poor manufacturing quality, unreasonable materials; b) Improper installation and adjustment
a) Poor lubrication,
b) Unreasonable assembly quality good;
c) poor manufacturing quality;
d) foreign matter in the oil
abnormal sound during operation; loose connection parts; large vibration of the whole machine, interference of rotating parts (during trial operation)
fault classification
fatal fault
serious fault
general fault
fault location
movable and fixed blade
cylindrical gear
bevel gear box
bevel gear pair
coupling||tt| |Commercial coupler
Upper feed roller tension spring
Speed change gear box
Upper feed roller slider
Gear connecting key
Steel leather machine upper casing
Steel grass machine blade
Steel grass machine
JB/T51022--1999
Table A1 (continued)
Failure mode
Severe wear or breakage
Severe wear or breakage
Serious oil leakage
Unstable operation
Separation, connection Failure of gear shifting
Difficulty in shifting gears or gear dropping
Too much grass
Causes and situations of failure
a) Blade hardness does not meet the requirements,
b) Blade material does not meet the requirements;
c) Blade gap changes
a) Poor lubrication;
b) Poor assembly quality;
c) Poor manufacturing quality
a) Poor lubrication
b) Poor manufacturing quality;
c) Poor assembly quality#
d) Shaft Socket hole machining out of tolerance
a) Gear box wall cracks;
b) Oil seal damage
a) Poor manufacturing quality, large meshing clearance,
b) Large bearing rate momentum
a) Unreasonable design;
b) Manufacturing and assembly do not meet requirements
a) Fork wear or breakage;
b) Axial movement of gears;
c) Toothed teeth are not in place
a) Fatigue fracture;
b) Too much preload
a) Positioning The frame is seriously worn;
b) The locking spring is broken and the elastic force is insufficient;
c) The shift fork is deformed, worn or broken
a) The manufacturing quality is poor;
b) The assembly does not meet the requirements
a) The blade becomes blunt;
b) The gap between the moving and fixed blades changes
a) The material is not good,
b) The manufacturing quality is poor;
c) The top screw is loose
The locking device has poor tightness
The grass mower with a productivity of not less than 2.5t/h has not passed There are no safety protection devices at the rotating parts of the load protection device
The main performance indicators drop below the specified values. The quality of the blade does not meet the relevant provisions of JB/T5178. There are no obvious signs on dangerous parts
Fault classification
General fault
Fault location
Drive belt
Discharge port
Pin of upper roller drive shaft
Protective cover
Bolts connecting the inlet and outlet hoppers and
Machine body
Fork bolt
JB/T 51022--1999
Table A1 (end)
Failure mode
Chain derailment or breakage
Deformation, falling off
Damage or no
a) Belt is too loose;
b) Load is too large
Failure causes and conditions
a) Poor assembly quality;
b) Axial movement of the sprocket;
c) The chain has Interference
a) The gap between the cutter head and the bottom cover is too large;
b) The discharge hopper is deformed
a) Poor assembly quality;
b) Excessive vibration
Fasteners are loose
a) Poor assembly quality:
b) The bolts have no locking device
Impact and vibration during work
Rivets are loose and fall off
Fault classification
Minor faultOverload operation
Irrational design
a) Poor manufacturing quality, unreasonable materials; b) Improper installation and adjustment
a) Poor lubrication,
b) Poor assembly quality;
c) Poor manufacturing quality;
d) Foreign matter in the oil
Abnormal sound during operation; Loosening of connecting parts; Large vibration of the whole machine, interference of rotating parts (during trial operation)
Fault classification
Fatal fault
Serious fault
General fault
Fault location
Moving and fixed blades
Cylindrical gear
Bevel gear box
Bevel gear pair
Coupling
Clutch
Upper feed roller tension spring
Speed change gear box
Upper feed roller Slider
Gear connecting key
Gang leather machine upper casing
Gang grass machine blade
Gang grass machine
JB/T51022--1999
Table A1 (continued)
Failure mode
Severe wear or fragmentation
Severe wear or fragmentation
Serious oil leakage
Unstable operation
Separation, connection Failure of gear shifting
Difficulty in shifting gears or gear dropping
Too much grass
Causes and situations of failure
a) Blade hardness does not meet the requirements,
b) Blade material does not meet the requirements;
c) Blade gap changes
a) Poor lubrication;
b) Poor assembly quality;
c) Poor manufacturing quality
a) Poor lubrication
b) Poor manufacturing quality;
c) Poor assembly quality#
d) Bearing matching hole machining is out of tolerance
a) Gear box wall cracks;
b) Oil seal damage
a) Poor manufacturing quality, large meshing clearance,
b) Large bearing rate momentum
a) Unreasonable design;
b) Manufacturing and assembly do not meet the requirements
a) The shift fork is worn or broken;
b) The gear moves axially;
c) The shift teeth are not in place
a) Fatigue fracture;
b) The preload force is too large
a) The positioning frame is seriously worn;
b) The locking spring is broken and the elastic force is insufficient;
c) The shift fork is deformed, worn or broken
a) The manufacturing quality of the disc is poor;
b) The assembly does not meet the requirements
a) The blade becomes blunt;
b) The gap between the moving and fixed blades changes
a) The material is not good,
b) The manufacturing quality is poor;
c) The top screw is loose
The locking device is poorly tightened
The grass machine with a productivity of not less than 2.5t/h has no overload protection device and no safety protection devices are installed on the rotating parts
The main performance indicators drop below the specified values. The quality of the blade does not meet the relevant provisions of JB/T5178. There is no obvious sign on the dangerous parts
Fault classification
General fault
Fault location
Drive belt
Discharge port
Pin of upper roller drive shaft
Protective cover
Bolts connecting the inlet and outlet hoppers and
machine body
Fork bolt
JB/T 51022--1999
Table A1 (end)
Failure mode
Chain derailment or breakage
Deformation, falling off
Damage or no
a) Belt is too loose;
b) Load is too large
Failure causes and conditions
a) Poor assembly quality;
b) Axial movement of the sprocket;
c) The chain has Interference
a) The gap between the cutter head and the bottom cover is too large;
b) The discharge hopper is deformed
a) Poor assembly quality;
b) Excessive vibration
Fasteners are loose
a) Poor assembly quality:
b) The bolts have no locking device
Impact and vibration during work
Rivets are loose and fall off
Fault classification
Minor faultOverload operation
Irrational design
a) Poor manufacturing quality, unreasonable materials; b) Improper installation and adjustment
a) Poor lubrication,
b) Poor assembly quality;
c) Poor manufacturing quality;
d) Foreign matter in the oil
Abnormal sound during operation; Loosening of connecting parts; Large vibration of the whole machine, interference of rotating parts (during trial operation)
Fault classification
Fatal fault
Serious fault
General fault
Fault location
Moving and fixed blades
Cylindrical gear
Bevel gear box
Bevel gear pair
Coupling
Clutch
Upper feed roller tension spring
Speed change gear box
Upper feed roller Slider
Gear connecting key
Gang leather machine upper casing
Gang grass machine blade
Gang grass machine
JB/T51022--1999
Table A1 (continued)
Failure mode
Severe wear or fragmentation
Severe wear or fragmentation
Serious oil leakage
Unstable operation
Separation, connection Failure of gear shifting
Difficulty in shifting gears or gear dropping
Too much grass
Causes and situations of failure
a) Blade hardness does not meet the requirements,
b) Blade material does not meet the requirements;
c) Blade gap changes
a) Poor lubrication;
b) Poor assembly quality;
c) Poor manufacturing quality
a) Poor lubrication
b) Poor manufacturing quality;
c) Poor assembly quality#
d) Bearing matching hole machining is out of tolerance
a) Gear box wall cracks;
b) Oil seal damage
a) Poor manufacturing quality, large meshing clearance,
b) Large bearing rate momentum
a) Unreasonable design;
b) Manufacturing and assembly do not meet the requirements
a) The shift fork is worn or broken;
b) The gear moves axially;
c) The shift teeth are not in place
a) Fatigue fracture;
b) The preload force is too large
a) The positioning frame is seriously worn;
b) The locking spring is broken and the elastic force is insufficient;
c) The shift fork is deformed, worn or broken
a) The manufacturing quality of the disc is poor;
b) The assembly does not meet the requirements
a) The blade becomes blunt;
b) The gap between the moving and fixed blades changes
a) The material is not good,
b) The manufacturing quality is poor;
c) The top screw is loose
The locking device is poorly tightened
The grass machine with a productivity of not less than 2.5t/h has no overload protection device and no safety protection devices are installed on the rotating parts
The main performance indicators drop below the specified values. The quality of the blade does not meet the relevant provisions of JB/T5178. There is no obvious sign on the dangerous parts
Fault classification
General fault
Fault location
Drive belt
Discharge port
Pin of upper roller drive shaft
Protective cover
Bolts connecting the inlet and outlet hoppers and
machine body
Fork bolt
JB/T 51022--1999
Table A1 (end)
Failure mode
Chain derailment or breakage
Deformation, falling off
Damage or no
a) Belt is too loose;
b) Load is too large
Failure causes and conditions
a) Poor assembly quality;
b) Axial movement of the sprocket;
c) The chain has Interference
a) The gap between the cutter head and the bottom cover is too large;
b) The discharge hopper is deformed
a) Poor assembly quality;
b) Excessive vibration
Fasteners are loose
a) Poor assembly quality:
b) The bolts have no locking device
Impact and vibration during work
Rivets are loose and fall off
Fault classification
Minor fault
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