GB/T 7948-2024 English PDFUS$279.00 · In stock
Delivery: <= 3 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 7948-2024: Plain bearings - Test method for PV limit of plastic bushes Status: Valid GB/T 7948: Historical versions
Basic dataStandard ID: GB/T 7948-2024 (GB/T7948-2024)Description (Translated English): Plain bearings - Test method for PV limit of plastic bushes Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: J12 Classification of International Standard: 21.100.10 Word Count Estimation: 14,158 Date of Issue: 2024-09-29 Date of Implementation: 2025-01-01 Older Standard (superseded by this standard): GB/T 7948-1987 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 7948-2024: Plain bearings - Test method for PV limit of plastic bushes---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.Plain bearings - Test method for PV limit of plastic bushes Sliding bearings - Plastic bushing limit PV test method ICS 21.100.10 CCS J 12 National Standard of the People's Republic of China Replace GB/T 7948-1987 Released on 2024-09-29 2025-01-01 Implementation State Administration for Market Regulation The National Standardization Administration issued ForewordThis document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1.Structure and drafting rules for standardization documents" Drafting is required. This document replaces GB/T 7948-1987 "Limit PV test method for plastic bearings". In addition to structural adjustments and editorial changes, the main technical changes are as follows. The scope of the standard has been changed (see Chapter 1, Chapter 1 of the 1987 edition); - Added the terms and definitions of "nominal contact area", "relative sliding velocity" and "specific load" (see 3.1, 3.2 and 3.3); - The definitions of "PV value" and "limit PV value" have been changed (see 3.4, 3.5, 1.1, 1.2 of the 1987 edition); - Added test principles (see Chapter 4); - Changed the instrumentation requirements (see Chapter 5, Chapter 3, 5.6, Figure 4 of the 1987 edition); - The specimen requirements have been changed (see Chapter 6, Chapter 2 of the 1987 edition); - The test environment and test preparation requirements have been changed (see 7.1, 7.2, Chapter 4 of the 1987 edition); - Added lubrication method (see 7.3); - The relative sliding linear velocity requirements have been changed (see 7.4, 5.2 of the 1987 edition); - The fit clearance requirements have been changed (see 7.5, 2.3 of the 1987 edition); - The test procedure has been changed (see Chapter 8, Chapter 5 of the 1987 edition); - Added test result assessment (see Chapter 9); - The calculation contents related to the limit PV value have been changed (see 10.3, 6.3 of the 1987 edition); - The contents of the test report have been changed (see Chapter 11, Chapter 7 of the 1987 edition). - Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents. This document was proposed by the China Machinery Industry Federation. This document is under the jurisdiction of the National Technical Committee for Standardization of Sliding Bearings (SAC/TC 236). This document was drafted by. Hefei Bolin New Materials Co., Ltd., China Machinery Productivity Promotion Center Co., Ltd., Shuangfei Oil-free Bearing Group Group Co., Ltd., Zhejiang Changsheng Sliding Bearing Co., Ltd., Zhejiang Zhongda Precision Parts Co., Ltd., Zhejiang Changsheng Plastic Shaft Cheng Technology Co., Ltd., Jiaxing Meitel Baoxin Machinery Industry Co., Ltd., China Machinery Testing Equipment Co., Ltd., Shandong Fuma Bearing Co., Ltd. Company, Huayi Bearing Technology (Jiangsu) Co., Ltd. This document is interpreted by the National Technical Committee for Sliding Bearing Standardization. This document was first published in 1987 and this is the first revision. Sliding bearings - Plastic bushing limit PV test method1 ScopeThis document describes the limiting PV values of plastic bushings in the form of rotational motion under dry friction, boundary lubrication with oil or grease. Test method. This document is applicable to the determination of the limiting PV value of plastic and plastic sleeves with plastic coverings. This document is not applicable to the determination of the limiting PV value of plastic bushings with oscillating or linear reciprocating motion.2 Normative referencesThe contents of the following documents constitute the essential clauses of this document through normative references in this document. For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies. in this document. GB/T 2889 (all parts) Terms, definitions, classification and symbols for sliding bearings GB/T 3974 Dimensions and tolerances of thermoplastic sleeves for sliding bearings GB/T 12613.1 Sliding bearing rolled sleeves Part 1.Dimensions3 Terms and definitionsGB/T 2889 (all parts) and the following terms and definitions apply to this document. 3.1 Nominal contact area projected bearing area The product of the bearing width and the inner bore diameter. Note. The projection area of the bearing surface (semi-cylinder) perpendicular to the load direction. 3.2 relative sliding linear velocity The relative sliding velocity between the shaft and the bearing surface. 3.3 specific bearing load Specific pressure The load per unit nominal contact area of a bearing. 3.4 PV value The product of specific load (P) and relative sliding velocity (V). 3.5 PV limit value The product of the limit load that the bearing can bear under a certain relative sliding linear velocity and the relative sliding linear velocity, or the product of the limit load that the bearing can bear under a certain relative sliding linear velocity. The product of the maximum relative sliding linear velocity that the bearing can withstand and the specific load. Note. The unit is MPa·m/s. ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 7948-2024_English be delivered?Answer: Upon your order, we will start to translate GB/T 7948-2024_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB/T 7948-2024_English with my colleagues?Answer: Yes. The purchased PDF of GB/T 7948-2024_English will be deemed to be sold to your employer/organization who actually pays for it, including your colleagues and your employer's intranet.Question 3: Does the price include tax/VAT?Answer: Yes. 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