GB/T 39655.2-2020Shipbuilding - Ship screw propellers - Manufacturing tolerances - Part 2: Propellers of diameter between 0.8 m and 2.5 m inclusive (English PDF)

Foreword

GB/T 39655 "Tolerances for manufacturing ship propellers for shipbuilding" is divided into two parts:

---Part 1: Propellers with a diameter greater than 2:5m;

---Part 2: Propellers with a diameter of 0:8m to 2:5m:

This part is Part 2 of GB/T 39655:

This section was drafted in accordance with the rules given in GB/T 1:1-2009:

The translation method used in this part is equivalent to ISO 484-2:2015 ``Shipbuilding Marine Propeller Manufacturing Tolerance Part 2: Diameter

Propellers from 0:8m to 2:5m":

The Chinese documents that have a consistent correspondence with the international documents cited in this section are as follows:

---GB/T 131-2006 Product Geometric Technical Specification (GPS) Representation of surface structure in technical product documents (ISO 1302:

2002, IDT):

This part was proposed and managed by the National Ocean Shipping Standardization Technical Committee (SAC/TC12):

Drafting organizations of this section: China State Shipbuilding Industry Research Institute, China Merchants Cruise Research Institute (Shanghai) Co:, Ltd:, Shanghai Overseas

Takahashi Shipbuilding Co:, Ltd:

1 Scope

This part of GB/T 39655 specifies the manufacturing tolerances for marine propellers with diameters ranging from 0:8m to 2:5m:

Note: In some cases, it is allowed to make some adjustments to the deviation based on the judgment of the customer or the designer and the customer:

2 Normative references

The following documents are indispensable for the application of this document: For dated reference documents, only the dated version applies to this document.

Pieces: For undated references, the latest version (including all amendments) applies to this document:

GB/T 9239:1-2006 Mechanical vibration constant (rigid) rotor balance quality requirements Part 1: Specification and balance tolerance

Inspection (ISO 1940-1:2003, IDT)

ISO 1302 Geometrical Product Specification (GPS) The representation of surface structure in technical product documents (GeometricalProduct

Specifications(GPS)-Indicationofsurfacetextureintechnicalproductdocumentation)

3 Scope of application

This section applies to integral, combined fixed pitch propellers and controllable pitch propellers:

4 Pitch measurement method

4:1 The principle of the measurement method is to measure the length PQ corresponding to the predetermined angle alpha along the helix of the radius r, and measure the points P and Q

The height difference h relative to the reference surface (see Figure 1):

The length of PQ can be measured by one of the methods described in 4:1:1, 4:1:2 or 4:1:3:

Note: If necessary, other methods that meet the accuracy requirements can be used: