JB/T 7296-1994 Technical Specifications for Diesel Engine Injection Nozzle Assemblies JB/T7296-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7296-94
Technical Conditions
Diesel Engine Injection Nozzle Assemblies
Published on 1994-07-18
Ministry of Machinery Industry of the People's Republic of China
Implemented on 1995-07-01
Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Diesel Engine Injection Nozzle Assemblies
1 Subject Content and Scope of Application
JB/T 7296-94
This standard specifies the technical requirements, inspection rules, marking, packaging, transportation and storage requirements for medium and small power diesel engine injection nozzle assemblies (hereinafter referred to as injection nozzle assemblies).
This standard applies to medium and small power diesel engine injection nozzle assemblies. 2 Reference standards
GB2828
GB2829
GB3077
GB9943
ZBJ94007
ZBJ94019
Counting sampling procedures and sampling tables for batch inspection (applicable to inspection of continuous batches)Counting sampling procedures and sampling tables for periodic inspection (applicable to inspection of production process stability)Technical conditions for alloy structural steel
Technical conditions for high-speed tool steel
Technical conditions for chromium bearing steel
Oil injection nozzle pairs, injection system plunger pairs, injection pump oil discharge pairsMetallurgical inspection of injection nozzles Magnetic particle inspection method for coupling parts, plunger coupling parts and oil delivery valve coupling parts Technical conditions for delivery and acceptance of diesel engine fuel injection nozzle coupling parts ZB/TJ94023
3 Technical requirements
3.1 Fuel injection nozzle coupling parts shall be manufactured according to product drawings and technical documents approved by prescribed procedures and shall comply with the requirements of this standard. 3.2 The needle valve body shall be manufactured of 18Cr2Ni4WA low carbon alloy steel or 25SiCrMoVA specified in GB3077: the needle valve shall be manufactured of W6Mo5Cr4V2 or W18Cr4V high speed tool steel specified in GB9943. The needle valve body and needle valve may also be manufactured of GCr15 ball bearing steel specified in YB9.
Under the condition of technical basis and with the consent of the user, the needle valve body and needle valve are allowed to be made of other grades of steel. 3.3 The needle valve body and needle valve shall be heat treated, and its metallographic structure shall comply with the provisions of ZBJ94007. If the materials used are not specified in ZBJ94007, the relevant technical documents shall apply. 3.3.1 The needle valve body made of 18Cr2Ni4WA or 25SiCrMoVA shall be carburized or carbonitrided, with a net carbon depth of 0.4-0.9mm and a hardness of not less than 57HRC. The carburizing depth on the sealing end face is allowed to be not less than 0.25mm, and the hardness is not less than 54HRC. In case of dispute over hardness, the Vickers hardness measurement method shall be used for arbitration; in case of dispute over the depth of the carbon layer, the effective hardened layer depth measurement method shall be used for arbitration. 3.3.2 The hardness of the needle valve made of W6Mo5Cr4V2 or W18Cr4V shall not be less than 60HRC. 3.3.3 The hardness of the needle valve body and needle valve made of GCr15 ball bearing steel should be 60-64HRC. 3.4 The main shape and position tolerances of the needle valve body and needle valve (referring to the requirements before mating) shall be as specified in Table 1. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
Part Name
JB/T729694
Roundness of the working surface of the inner cylinder that matches the needle valve
Straightness of the axis of the working surface of the inner cylinder that matches the needle valveParallelism of the working surface of the inner cylinder that matches the needle valveOblique runout of the working surface axis of the inner cylinder of the sealing faceRoundness of the sealing cone
Radial runout of the positioning outer circle to the axis of the working surface of the inner cylinderRadial runout of the small outer circle to the large outer circle
Verticality of the bearing end face or the sealing end face to the axis of the working surface of the inner cylinderParallelism of the sealing end face to the bearing end face
Flatness of the sealing facebZxz.net
Angular deviation between the axis of the spray hole and the axis of the body (hole type, long hole type)Circumference Angular deviation of the center line of each nozzle hole (hole type, long hole type) Large end at the nozzle end
Small end at the nozzle end
Long hole type
Machining
Compensation
Slight runout of the sphere or circular body of the nozzle head to the inner cylinder working axis (hole type, long hole type
The straightness of the cylinder working surface axis matched with the needle body The straightness of the cylinder working surface axis matched with the needle body The parallelism of the needle body working surface line Sealing surface and the outer circumference close to the sealing surface The oblique runout of the cylinder working surface axis of the shaft to the cylinder working surface axis (axial needle type) The radial runout of the outer surface close to the sealing surface to the cylindrical working surface axis The surface roughness of the main parts of the needle valve body and the needle valve shall be as specified in Table 2. Table 2
Zero Part name
Surface roughness items
Surface roughness of the inner cylindrical working table matched with the needle valve. The surface roughness of the allowable local grinding scratches and the surface roughness of the matching grinding process. The surface roughness of the sealing cone
Surface roughness of the sealing end face
Surface roughness of the outer cylindrical working table matched with the needle valve body. The surface roughness of the allowable local grinding scratches and the surface roughness of the matching grinding process. The surface roughness of the conical surface
The allowable value of R.
3.6 The lift deviation of the needle valve in the needle valve body: JB/T7296-94
When the lift is greater than or equal to 0.4mm, the deviation is ±0.05mm; when the lift is less than 0.4mm, the deviation is ±0.03mm. 3.7 Needle valve body and needle valve according to ZBJ94019 3.8 The sealing end face of the needle valve body, the nozzle orifice and the needle head of the needle valve are not allowed to have burrs and damage. 3.9 The needle valve should have good sliding properties in the needle valve body. 3.10 There should be a certain radial clearance between the matching cylindrical working surfaces of the needle valve body and the needle valve. When the diameter sealing value is evaluated by the oil pressure method, the value should comply with the provisions of Table 3.
Type of coupling
Axis needle type and S series long hole type
Short hole type
Sealing value8
Pressure drop model MPs
From 20 to 18
From 20 to 18
Note: 1) For the injection coupling with a diameter of 6mm and made of 18Ct2Ni4WA, the diameter sealing value is allowed to be 5~138. 3.11 The sealing cone surface of the injection nozzle coupling should be sealed. 3.12 The spray quality of the nozzle pair should meet the following requirements: 3.12.1 The fuel sprayed by the nozzle pair should be in a mist, and there should be no obvious visible mist deflection and splashing oil particles, continuous oil columns and easily distinguishable local uneven concentration. 3.12.2 The injection should be crisp and accompanied by a sound corresponding to the structure of the nozzle pair. 3.12.3 It is allowed to use the nozzle pair samples agreed with the user for comparative evaluation. 3.13 The deviation rate of the maximum and minimum flow values ​​of the nozzle pair to the arithmetic mean of the flow of the tested pair should not exceed ±3%, otherwise flow grouping should be carried out. The flow deviation rate of the maximum and minimum flow values ​​in the same group of nozzle pairs to the calibration value of the group should not exceed ±2%. The flow grouping requirements of the nozzle pair are agreed upon by the user and the manufacturer. 3.14 The reliability index of the fuel injection nozzle is calculated according to formula (1): MTTF-
Wherein: MTTF is the average working time before failure, ht+(nr)TJ
K. Acceleration factor, that is, the number of working cycles of the fuel injection nozzle pair per revolution of the fuel injection pump on the test bench: r—the number of samples that fail within the test deadline: - the number of reliability test samples:
T. .Test truncation time, h
t.—the time when the fuel injection nozzle pair fails, h. When r=0, let MTTF=2nT. .
3.1S The reliability index (MTTF) value of the fuel injection nozzle assembly shall be agreed upon by the supplier and the buyer. (1)
3.16 If the user complies with the instruction manual, the warranty period of the fuel injection nozzle assembly is one year from the date of leaving the factory, and the cumulative use time shall not exceed 1200 hours. If it is damaged or cannot be used properly due to the manufacturer's responsibility, the manufacturer shall replace it. 4 Inspection rules
4.1 The fuel injection nozzle assembly shall be inspected and qualified by the manufacturer's quality inspection department in accordance with this standard. 4.2 The factory inspection items are generally 3.9, 3.10, 3.11, and 3.12. The sampling rules and the judgment of whether it is qualified or not shall be in accordance with the relevant provisions of GB2828; the sampling rules and the judgment of whether it is qualified or not shall be in accordance with the relevant provisions of GB2829 for type inspection. 4.3 The acceptance of the distributor and supporting units shall comply with the relevant provisions of ZB/TJ94023. 3
5Marking, packaging, transportation and storage
JB/T7296-94
5.1 Each pair of fuel injection nozzles shall be marked with the factory logo or trademark and model of the manufacturer. The logo shall remain clear and recognizable during the service life. 5.2 Each pair of fuel injection nozzles shall be treated with corrosion protection and packaged. 5.3 The fuel injection nozzles that have been treated with corrosion protection and packaged shall be packed together with the product certificate signed by the inspector and relevant factory documents into a moisture-proof packaging box. The outside of the packaging box shall be marked with: a.
Name;
Product model:
Standard number:
Quantity:
Packing date (year and month):
Factory logo or trademark of the manufacturer;
Manufacturer,
Transport protection mark.
The weight of each packaging box shall not exceed 30kg.
5.4The packaging shall fully ensure that the fuel injection nozzles will not be damaged or damp during transportation. 5.5 The nozzle parts should be stored in a dry warehouse and should not be stored together with acid, alkali and other chemicals that can cause corrosion. Under normal storage conditions, the manufacturer should ensure that the product will not rust within one year from the date of leaving the factory. Additional remarks:
This standard is proposed and managed by Wuxi Oil Pump and Nozzle Research Institute of the Ministry of Machinery Industry. This standard was drafted by Wuxi Oil Pump and Nozzle Research Institute and Shanghai Internal Combustion Engine Research Institute. Wuxi Oil Pump and Nozzle Factory, Shanghai Diesel Engine Factory Oil Pump Branch, Luoyang First Tractor Factory Oil Pump Branch and other units participated in the drafting.
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