GB/T 304.3-2023Spherical plain bearings—Part 3:Fits (English PDF)

Foreword

This 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.

This document is the third part of GB/T 304 "Spherical Bearings". GB/T 304 has released the following parts.

---GB/T 304.1-2017 Classification of spherical plain bearings;

---GB/T 304.2-2015 Code method for spherical plain bearings;

---GB/T 304.9-2021 Spherical bearings Part 9: General technical rules.

This document replaces GB/T 304.3-2002 "Spherical Bearing Fits". Compared with GB/T 304.3-2002, except for editorial changes, The main technical changes are as follows:

a) Two chapters "Terms and Definitions" and "Symbols" have been added (see Chapters 3 and 4);

b) Deleted the description of coordination category (see 3.1 and 3.2 of the 2002 edition);

c) The requirements for the fit of large-size bearings are added (see Table 3, Table 4, Table A.1 and Table A.2);

d) Changed the expression of the overall principle of coordination selection (see Chapter 5, 4.1~4.4 of the 2002 edition);

e) Added the requirements for the thread tolerance zone connected with the bearing (see 6.2);

f) Integrates the geometric tolerance table (see Table 3, Table 4 and Table 5 of the 2002 edition).

Introduction

Joint bearings are spherical plain bearings, mainly suitable for swinging motion, tilting motion and low-speed rotary motion. GB/T 304 "joint shaft "Bearing" is the basic and universal standard to guide the production of spherical plain bearings in my country, and consists of four parts.

--- Part 1. Classification. It aims to clarify the product types and classification management of spherical plain bearings.

--- Part 2. Code method. It aims to standardize the compilation method of joint bearing codes.

--- Part 3. Coordination. It is designed to guide bearing users to correctly select the shaft and housing hole diameters that match the bearings according to the working conditions. Differential belt to ensure the normal operation of the bearing in use.

--- Part 9. General technical rules. It aims to guide the production, selection, procurement, inspection and acceptance of bearings.

1 Scope

This document specifies the cooperation between spherical plain bearings (hereinafter referred to as "bearings"), shafts and housing holes and threaded connections under general working conditions.

The selection principle, the recommended tolerance zone, the geometric tolerance and surface roughness of the shaft and bearing housing hole, etc.

This document applies to the design of bearing fits in the following cases.

---Bearing dimensions comply with GB/T 9161-2001 (except K series), GB/T 9162-2001, GB/T 9163-2001 (except for K, W series), GB/T 9164-2001 and the bearing nominal inner diameter d<=1250mm, nominal outer diameter D <=2000mm;

--- Bearing radial clearance conforms to the N group specified in GB/T 9161-2001 and GB/T 9163-2001;

---The matching shaft is a solid shaft or a thick-walled hollow shaft;

---The operating temperature does not exceed 100°C.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 197 Common thread tolerances

GB/T 1800.1 Geometric Product Specifications (GPS) Linear Dimensional Tolerances ISO Code System Part 1: Tolerances, Deviations and basis of cooperation

GB/T 3944 Glossary of spherical plain bearings

3 Terms and Definitions

The terms and definitions defined in GB/T 1800.1 and GB/T 3944 apply to this document.

4 Symbols

The following symbols apply to this document.

D: Nominal outer diameter of the bearing

Da: the nominal diameter of the housing hole that fits the bearing

d: Nominal inner diameter of the bearing

da: the nominal diameter of the shaft mated with the bearing

t: cylindricity tolerance of the journal/housing surface mated with the bearing

t1: Axial circular runout tolerance of the shaft shoulder/housing shoulder mated with the bearing

t2: Parallelism tolerance of both ends of the gasket

deltaDmp: Average outer diameter deviation of a single radial plane of the bearing

deltadmp: Average inner diameter deviation of a single radial plane of the bearing