GB/T 12458-2017Coupling - Classification (English PDF)

Foreword

This standard is drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 12458-2003 Coupling - Classification. Apart from editorial changes, the main technical changes with respect to GB/T 12458-2003 are as follows: in 5.2 the title of the subclause has been changed to "group code, variety code and structural type code of the coupling" and the remainder of the content has been changed to the content of 5.2; and the way in which plum-blossom elastic couplings and elastic pin gear couplings are classified has been changed.

This standard was proposed by, and is under the jurisdiction of, the National Technical Committee on Machine Shafts and Accessories of Standardization Administration of China (SAC/TC 109).

The drafting organisations of this standard are the China Machinery Productivity Promotion Centre, the Yueqing Coupling Factory, Zhejiang Huatai Coupling Co. Ltd., Deyang Lida Basic Parts Co. Ltd. and Wuhan Zhengtong Transmission Technology Co. Ltd.

The previous editions of the standard replaced by this one are GB/T 12458-1990 and GB/T 12458-2003.

1 Scope

China's national standard that classifies shaft couplings and lays down how their model designations are built. A coupling is the component that joins two shafts so that one drives the other, and the variety of them is extraordinary: rigid flange couplings that treat the two shafts as one, gear and chain couplings that tolerate misalignment without any elastic element, diaphragm and spring couplings that flex in metal, rubber-element couplings that damp torsional shock, universal joints that transmit torque through an angle, and safety couplings that are designed to let go before the machine breaks. A designer choosing among them, and a purchaser ordering one, need a common vocabulary and a common naming scheme, otherwise the same product carries three names in three catalogues. This standard supplies both. It sets out the full classification tree - rigid couplings, flexible couplings without and with elastic elements, metallic and non-metallic elastic elements, and rigid and flexible safety couplings - down to individual structural types such as the drum-shaped gear coupling with a brake wheel or the plum-blossom elastic coupling with a flange. It then defines how a model designation is assembled from the group code, the variety code, the structural type code and the size code, how those codes are derived from the pinyin initials of the Chinese name, and how the size code relates to the nominal torque series in GB/T 3507; Table 1 ties every name in the classification to its resulting model. It applies to couplings generally, and the 2017 edition reworked the coding subclause and changed how plum-blossom elastic couplings and elastic pin gear couplings are classified.

This standard specifies the classification of couplings and the method of designating their models.

This standard applies to couplings.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 3507 Nominal torque series of couplings.

GB/T 3852 Shaft hole and connection type and dimensions of coupling.

GB/T 3931 Couplings - Terminology.

3 Terms and definitions

The terms and definitions given in GB/T 3931 apply to this document.

5 Method of designating coupling models

The model of a coupling is made up of the group code, the variety code, the structural type code and the size code.

The group code, the variety code and the structural type code of a coupling take as the code the first Chinese pinyin letter of the first character of the name. Where this would be repeated, the second letter is used, or the first or second pinyin letter of the second or third character of the name, or the first or second pinyin letter of a character with distinctive features in the name, on the principle that within the same group, variety and structural type the codes shall not be repeated.

The main parameter of a coupling is the nominal torque Tn, expressed in newton metres (N.m); its value shall comply with GB/T 3507.

The serial number of the nominal torque of the coupling, or a dimensional parameter, is the size code of the coupling.

The method of designating coupling models is shown by the diagram in the standard: from left to right, the group code, the variety code, the structural type code and the size code. Example: in GB/T 10614, the basic-type core elastic coupling with the nominal torque given in the example has the model LN5, and the double-flange core elastic coupling has the model LNS5.

The names and the models of couplings shall be as specified in Table 1. Table 1 sets out, for each category and subcategory, the name and code of the group, the name and code of the variety and the name and code of the structural type, and gives the resulting name and model of the coupling.