GB/T 21955-2008Tractors and machinery for agriculture and forestry - Paper friction disc - Technical specifications (English PDF)

Foreword

The Standard Appendix A, Appendix B and Appendix C are normative appendix. The standard proposed by China Machinery Industry Federation. This standard by the National Standardization Technical Committee of the tractor. This standard was drafted. Hangzhou Institute of powder metallurgy. The main drafters of this standard. Liu Youde, Lu Naiguang, Daiguo Wen. Tractors and machinery for agriculture and forestry Paper-based friction plates and technical conditions

1 Scope

GB/T 21955-2008 is the Chinese national standard on tractors and machinery for agriculture and forestry - paper friction disc - technical specifications, in the field of agriculture. The /T suffix marks it as a recommended standard: it is not compulsory by itself, but it becomes binding as soon as a contract, a tender or a customer specification calls it up - which in practice is how most foreign buyers meet it. It was issued on 3 June 2008 by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China; Standardization Administration of China, and has been in force since 1 January 2009. Classification: ICS 65.060.10, CCS T63. This page is published from the official record of the standard held by the Chinese standards administration: the identification, the dates, the classification and the issuing body are taken from there. The clause text, the tables and the numeric limits are in the document itself, which is delivered complete in English translation.

This standard specifies the technical requirements for agricultural and forestry tractors and machinery and paper-based friction plate, test methods, inspection rules, marking, packaging, storage Memory and so on. This standard applies to all types of agricultural and forestry tractors and machinery wet clutch and brake Paper based friction plates (hereinafter referred to as friction plates).

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

GB/T 2828.1 Sampling procedures for inspection - Part 1. by acceptance quality limit (AQL) retrieval batch inspection sampling plan ( GB/T 2828.1-2003, ISO 2859-1.1999, IDT)

GB/T 3478 (all parts) Straight cylindrical involute splines

GB/T 10095 (all parts), precision cylinder gear system

GB/T 12767-1991 metallurgy products surface roughness parameters and their values

GB/T 13237 quality carbon structural steel sheets and strips

GB/T 13384 mechanical and electrical products packaging General technical conditions

JB/T 7909 Wet sintered metal friction material performance test table test method

3 Technical requirements

3.1 friction plate shall comply with the requirements of this standard, in accordance with prescribed procedures for approval of product manufacturing drawings and technical documents, there is no standard for this Covering some special requirements, supply and demand sides can sign a separate technical documents.

3.2 Friction Materials According to conditions of use and friction plate friction material to withstand the load size, the friction plate friction material is divided into I, II two types of performance indicators Standard set forth in Table 1. Table

1 Types of Energy load allowable value Cm Dynamic friction coefficient µd Coefficient of static friction µs Wear rate × 10-8cm3/J Scope (Reference) I 8500 ~ 32000 0.11 ~ 0.14 0.12 ~ 0.17 <=5 for the clutch and brake light load II > 32000 0.11 ~ 0.14 0.12 ~ 0.17 <=5 for high load clutches and brakes NOTE. The energy load allowable value Cm terminology and symbols, measurement and calculation, see JB/T 7909.

3.3 friction layer

3.3.1 friction layer thickness and generally 0.5mm ~ 1.5mm.

3.3.2 friction layer should cover the core plates root circle, bore or outer edge of the core plate must not be exceeded, but allows retracted.

3.3.3 friction layer does not allow any blistering, delamination, cracking, creases and other defects.

3.3.4 Surface roughness friction layer shall comply with GB/T 12767, and shall not be greater than R Rao 3.2µm.