This standard specifies the technical requirements, inspection methods, acceptance rules, storage, packaging, custody and marking of carburetor valve needle profiles. This standard applies to the valve needle profiles of the fuel inlet needle valve of the carburetor for gasoline engines. JB/T 7146.1-1993 Carburetor valve needle profiles JB/T7146.1-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7146.1-93
Carburettor Valve Needle Profile
Published on November 21, 1993
Ministry of Machinery Industry of the People's Republic of China
Implemented on March 1, 1994
Mechanical Industry Standard of the People's Republic of China
Carburettor Valve Needle Profile
1 Subject Content and Scope of Application
JB/T 7146.1—93
This standard specifies the technical requirements, inspection methods, acceptance rules, storage, packaging, custody and marking of carburettor valve needle profiles. This standard applies to the valve needle profile of the fuel inlet needle valve of the carburettor for gasoline engines. 2. Reference standards
GB1800
GB1801
GB1802
GB1083
GB/T1804
GB2828
3 Technical requirements
Tolerance and fit General standard tolerance and basic deviation Tolerance and fit: Tolerance and fit of holes and shafts with dimensions up to 500mm Tolerance and fit of holes and shafts with dimensions greater than 500~3150mm Commonly used holes and shafts Tolerance and fit of holes and shafts with dimensions up to 18mm General tolerance Unknown tolerances of linear dimensions
Batch inspection Count sampling procedures and sampling tables (applicable to continuous batch inspection) 3.1, the material is stainless steel, copper, aluminum alloy, and the technical conditions and variety specifications of the material are determined by the broad needle profile manufacturer. 3.2 The cross-sectional shape of the profile is four-calibration type or three-prism type. 3.3 The basic dimensions of the outer diameter are preferably 3.5, 4, 4.5, 5, 5.5, 6mm. 3.4 The dimensional deviation of the outer diameter shall comply with the provisions of h8 in GB1800. The surface straightness tolerance is 0.03/100mm. 3.5www.bzxz.net
The circumference tolerance is 0.01mm.
The coaxiality tolerance of the inscribed circle of the outer diameter and the outer diameter is 0.05mm. 3.7
3.8 The surface roughness R value is 0.8μm.
The surface hardness of the outer diameter shall be agreed upon by the supply and demand parties, and the appearance shall be smooth and shall not have defects such as bumps, cracks, indentations, flash, burrs, defects, rust and pollution. Each length is 2~3m, or agreed upon by the supply and demand parties. 4 Inspection method
Enlarge the cross section of the profile for inspection.
4.2 Basic dimensions, dimensional tolerances, and roundness tolerances shall be inspected at each measuring point in any two radial directions using an outside micrometer or special measuring tool, and no less than 5 points shall be sampled for each profile.
4.3 Surface straightness and coaxiality of the inscribed circle and the outside diameter shall be inspected using a special inspection tool. 4.4 Surface hardness shall be inspected using a hardness tester.
4.5 Surface roughness and appearance quality shall be inspected by visual inspection and comparison with a sample block or using a special inspection tool. 5 Acceptance rules
According to the normal sampling plan specified in GB2828, the general inspection level is 1, and the unqualified classification and AQL value are specified in the following table. Approved by the Ministry of Machinery Industry on November 21, 1993
Implemented on March 1, 1994
6 Marking
Unqualified classification
Marking example:
JB/T7146.1-93
Dimension deviation
Straightness tolerance
Roundness tolerance
Coaxiality of inscribed circle and outer diameter
Surface roughness|| tt||Appearance quality
Outer diameter size
No. of this standard
The valve needle profile with an outer diameter of 3.5mm and a material of 3Cr13 that meets the requirements of JB/T7146.1 is marked as: JB/T7146.1-3.5-3Cr13
The valve needle profile with an outer diameter of 6mm and a material of LF2 that meets the requirements of JB/T7146.1 is marked as: JB/T 7146.1-6.0-LF2
7 Packaging and storage
The packaging should be rainproof, moisture-proof, rust-proof and anti-collision. The material, specification, quantity, quality and implementation standard number should be indicated on the packaging surface. 7.1
7.2 It should be stored in a well-ventilated, dry, covered warehouse without corrosive gas or liquid. Additional Notes:
This standard was proposed and managed by Tianjin Internal Combustion Engine Research Institute, and was drafted by Tianjin Internal Combustion Engine Research Institute. The main drafter of this standard is Zhong Maosheng.
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