Mechanical Industry Standard of the People's Republic of China JB/T50143-1999 Hydraulic Dynamometer Product Quality Classification (Internal Use) Published on 1999-12-30 National Bureau of Machinery Industry Implemented on 2000-06-01 JB/T50143—1999 This standard is used in conjunction with JB/T9870—1999 "Hydraulic Dynamometer". This standard is proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The drafting units of this standard are Qidong Dynamometer Factory and Shanghai Internal Combustion Engine Research Institute. The main drafters of this standard are Li Hui, Wu Qisheng, Chen Jianhui, Huang Zhiping, and Qu Junming. This standard was first issued in December 1999. 1 1 Scope Machinery Industry Standard of the People's Republic of China Hydraulic Dynamometer Product Quality Grading (Internal Use) JB/T50143—1999 This standard specifies the quality indicators, test methods and inspection rules for the three grades of hydraulic dynamometer (hereinafter referred to as dynamometer) products: qualified products, first-class products and superior products. This standard applies to the quality inspection and grade assessment of dynamometer products for internal combustion engines. 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 are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2828——1987 JB/T9870—1999 3 Quality indicators 3.1 Technical requirements Batch inspection counting sampling procedures and sampling tables (applicable to the inspection of continuous batches) Hydraulic dynamometer Dynamometer products should be manufactured according to product drawings and technical documents approved by the prescribed procedures and comply with the provisions of relevant standards. 3.1.1 3.1.2 Dynamometer products are classified into three grades according to their different quality indicators: qualified products, first-class products and superior products. The main performance indicators are shown in Table 1. Main performance indicators Static torque measurement error Static torque sensitivity Constant torque adjustment error (with electronic control device) Constant speed adjustment error (with electronic control device) Speed measurement error ≤1000r/min >1000r/min 3Reliability assessment indicators See Table 2, Assessment indicators Qualified products approved by the State Machinery Industry Bureau on December 30, 1999 Qualified products ±5rmin Large range%||t t||±1r/min ±0.1%±1 word Superior product ±2r/min Superior product 2000-06-01 implementation Mean working time before first failure MTTFF Mean time between failures MTBF 3.4 Durability index JB/T50143-1999bzxz.net Under a load not less than 50% of the rated load of the dynamometer, the cumulative continuous test time is not less than 2000h, which can be combined with user use test. 3.5 Assembly quality 3.5.1 The rotor parts shall be dynamically balanced according to the requirements of the product drawings, and the dynamic balance accuracy shall not be lower than G2.5. 3.5.2 The cones at both ends of the main shaft shall match the coupling, and the contact area shall not be less than the following provisions: 70% of qualified products, 75% of first-class products, and 3.5.3 There shall be no water or oil leakage at the joints of the sealing surfaces. 3.5.4 The assembly of the whole machine shall meet the requirements of the product drawings, and the moving parts shall be flexible and without abnormal sounds. Appearance quality The appearance shall be free of damage, obvious bruises, rust and other defects. 3.6.2 Exposed fasteners, connectors, operating parts, etc. shall be protected and decorated according to relevant requirements. 3.6.3 The paint layer shall be uniform, smooth and firm, and shall not have delamination or peeling. 3.6.4 The dial scale font shall be clear and beautiful. The digital display of the instrument shall be correct. The label is correctly marked and consistent with the product. 3.6.5 Test method The test method shall be in accordance with the provisions of Chapter 6 of JB/T9870-1999. 5 Inspection rules Inspection rules shall be in accordance with the provisions of Chapter 7 of JB/T9870-1999. 5.1 Sampling method Sampling rules The sampling inspection plan for dynamometer products shall be prepared in accordance with the counting procedures and sampling tables specified in GB/T2828. Unqualified classification Any product whose quality characteristics do not meet the standards or drawings is called unqualified. According to its importance to product quality, unqualified products are generally divided into: Class A unqualified, Class B unqualified and Class C unqualified. Class A unqualified products are extremely important quality characteristics that do not meet the requirements. Class B unqualified products are important quality characteristics that do not meet the requirements. Class C unqualified products are general quality characteristics that do not meet the requirements. See Table 3 for the unqualified classification of dynamometer products. Table 3 Unqualified classification Speed measurement error Static torque measurement error Quality characteristics 3 Acceptable quality level AQL value JB/T50143-1999 Static torque sensitivity Durability Constant torque adjustment error (with electronic control device) Constant speed adjustment error (with electronic control device) Unbalance of rotor components Conical surfaces at both ends of the spindle and Contact area of coupling Sealing of each joint Assembly quality of the whole machine Insulation resistance of electronic control device Appearance quality (main machine and electronic control device) Quality of paint layer Scale scale, words Signage mark Determine the AQL values of three levels according to qualified products, medium products and superior products, see Table 4. 5.4 Determination of sampling plan 5.4.1 Use a normal sampling plan. 2 Use special inspection level S-1. 5.4.3 Select inspection batch N=26~50, sample n=2, and the inspection batch can also be determined according to the actual batch of the manufacturer, but it must not be less than 5 units. 5.4.4 The sampling plan of dynamometer products is shown in Table 4. Unqualified classification Inspection level Sample code Number of samples n Qualified products First-class products Superior products Ac, Re 5 Implementation of sampling inspection and grade assessment Sampling judgment plan for dynamometer products N-26~50 5.5.1 The required samples of dynamometers shall be taken from users or manufacturers according to Table 4. The products taken shall be qualified products produced recently (within half a year). 5.5.2 Sampling shall be carried out suddenly and randomly. JB/T50143—1999 5.5.3 When sampling at the production plant, the parent of the sample shall comply with the provisions of 5.4.3. When sampling at the user or production line, it may not be restricted by the lower limit of the batch range value. 5.5.4 Quality grade assessment After all samples have been inspected, when the number of unqualified items of each category in the sample is less than or equal to the Ac value of the superior product, the product under review is a superior product; when the number of unqualified items of each category in the sample is less than or equal to the Ac value of the first-class product, the product under review is a first-class product; if the number of unqualified items of one category in the sample is less than or equal to the Ac value of the qualified product, the product under review is a qualified product; if the number of unqualified items of one category in the sample is greater than or equal to the Re value of the qualified product, the product under review is a non-qualified product. After a product is rated as non-qualified, it is allowed to be re-inspected once half a year later. If the supplementary inspection is qualified, it can still be rated as a qualified product, but it cannot be rated as a first-class product or a superior product. 4 Republic Mechanical Industry Standard Hydraulic Dynamometer Product Quality Grading (Internal Use) JB/T50143—1999 Published and Distributed by the Mechanical Science Research Institute Printed by the Mechanical Science Research Institute (No. 2, Shouti South Road, Beijing, Postal Code 100044)* Format 88 0×1230 2Words 1Q000 1/16Printing sheet 1/2 First edition in April 2000 Printing quantity 1-500 First printing in April 2000 Price 1000 yuan 99-1254 Mechanical Industry Standard Service Network: http/kvwwJB.ac.cn666 Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.