1 Scope
This document specifies the classification, technical requirements, test methods, inspection rules, marking, packaging and transport of central rotary joints for hydraulic excavators.
This document applies to central rotary joints for hydraulic excavators, cranes, aerial work vehicles, shield machines, rotary drilling rigs, motor graders, offshore platforms and other mechanical equipment with central rotary joints can be used with reference.
2 Normative references
The contents of the following documents constitute the essential provisions of this document through the normative references in the text. Among them, note the date of the reference document, only the date of the corresponding version applies to this document; do not note the date of the reference document, its latest version (including all the revision of the list) applies to this document.
GB/T 2828.1 Counting sampling inspection procedures Part 1: Lot-by-lot inspection sampling plan by acceptance quality limit (AQL) retrieval GB/T 7932 General rules and safety requirements for pneumatic systems and their components
GB/T 7935 General technical conditions for hydraulic components
GB/T 13306Labeling
GB/T 14039-2002 Hydraulic transmission fluid solid particles pollution level code
GB/T 17446 Glossary of fluid transmission systems and components
GB/T 17489 Hydraulic particle contamination analysis of fluid samples extracted from working system lines
JB/ T 7858 Hydraulic component cleanliness assessment methods and hydraulic component cleanliness indicators
3 Terms and definitions
The terms defined in GB/T 17446 and the following terms and definitions apply to this document.
3.1
Central turning joint
The hydraulic and pneumatic system piping that connects the fixed part of the hydraulic excavator with the rotating part, so that the upper and lower parts of the system piping have 360° relative rotary movement without interference.
4 Marking
4.1 Marking method
The marking method of the central swivel joint (see Figure 1) is as follows:
4.2 Marking instructions
4.2.1 Number of channels: indicated by the number "01~99".
4.2.2 Flow rate code: rounded to the nearest two digits "00~99" after dividing the flow rate by 10.
4.2.3 Rotation mode: expressed by the number "A" or "B", where A means fixed body and B means fixed shaft.
4.2.4 Series number: The number "0 to 9" is used. The initial series number is indicated by OO.
4.2.5 Change version number: indicated by the two digits "00 to 99", the original version number being "00".
4.3 Marking examples
A central rotary joint with 6 channels, fixed body, main channel flow rate 70 L/min, series number 0, change of version number 00 is marked as follows:
ZHO607A00o
5 Technical requirements
5.1 General requirements
5.1.1 The mechanical properties of the recommended materials for the rotary body of the central swivel joint are shown in Table 1.
5.1.2 The central swivel joint shall be flexible and smooth in the process of rotation, without stalling or overheating, and shall be free from external leakage.
5.1.3 The surface of the rotary body of the central rotary joint shall be flat and smooth, and there shall be no process defects affecting the appearance quality. The coating on the exposed non-machined surface shall be uniform and of the same colour.
5.2 Maximum working pressure
The maximum working pressure shall be 1.25 times the rated working pressure, and the pressure drop shall not be greater than 0.1 MPa within 2 min after the maximum working pressure is added to each interface respectively.
5.3 Starting resistance torque and slewing resistance torque
The starting resistance torque shall not be greater than 350 N-m and the slewing resistance torque shall not be greater than 250 N-m.
5.4 Pressure loss
The pressure loss at the main hydraulic line interface should not be greater than 0.6 MPa in the forward and reverse directions, and the pressure loss at the pilot interface should not be greater than 0.06 MPa. The pressure loss at the air line interface should not be greater than 0.06 MPa.
5.5 Sealing requirements
The leakage volume in each interface of the hydraulic line should not be greater than 10 mL/min. The leakage volume in each interface of the gas line should not be greater than 0.01 MPa/20 s. 5.6 Cleanliness requirements
The internal cleanliness index of the oil taken out of the central rotary joint shall not be greater than the /18/15 specified in GB/T 14039-2002. 5.7 Durability requirements The leakage volume of the adjacent two interfaces shall not be greater than 25 mL/ min when the central rotary joint is rotated continuously for 300,000 revolutions at the rated pressure and rotation speed of 10 r/min~15 r/min.
5.8 High and low temperature requirements
Central rotary joint in the ambient temperature: low temperature: -30 ℃ ± 5 ℃, high temperature: 40 ℃ ± 5 ℃, rated pressure and rotation speed 10 r / min ~ 15 r / min, high and low temperature continuous rotation of 150,000 revolutions or 250 h, the leakage of the adjacent two interfaces should not be greater than 25 mL / min.
5.9 Impulse requirements
Central rotary joint in the rotary speed of 10 r/min ~ 15 r/min, continuous pulse pressure, test 500,000 times, the adjacent two interface leakage should not be greater than 30 mL / min.
5.10 Bursting requirements
The central rotary joint shall not crack under 3 times the maximum working pressure.
5.11 Other requirements
Other requirements of the central rotary joint should be in accordance with GB/T 7932 and GB/T 7935.
6 Test methods
6.1 Hydraulic line test
6.1.1 Test preparation
6.1.1.1 Various instruments and gauges should be measured and certified before use.
6.1.1.2 The kinematic viscosity of the test medium at 40°C is 42 mm2/ s~74 mm2/ s.
6.1.1.3 The temperature of the test medium is 50 ℃ ± 5 ℃, the solid particle contamination level of the test system oil should not exceed GB/T 14039-2002 /18/15.
6.1.1.4 no-load rotation for 3 min, rotation speed of 8 r/min ~ 15 r/ min.
6.1.1.5 measurement accuracy level and test with measuring instruments allowed system error see table 2. measurement accuracy level is divided into A, B, C. A level for particularly accurate measurement of the performance of the test specimen test, B level for the type test, C level for the factory test.
6.1.2 Test conditions
6.1.2.1 The test shall be carried out on the test bench or on the corresponding load-bearing machine.
6.1.2.2 The flow rate of the oil source shall be adjustable and shall be greater than the maximum flow rate for the central swivel joint test. The pressure of the oil source shall be capable of exceeding the maximum working pressure of the central swivel joint under test by 20% to 30% for a short period of time.
6.1.2.3 It is permitted to add additional components to the given basic circuit to regulate pressure and flow or to ensure the safe operation of the test system, provided that the performance of the central reversing joint under test is not affected.
6.1.3 Test procedure
6.1.3.1 Starting resistance torque test
The torque is measured and recorded using a tensiometer at the moment of rotation of the rotary joint, once on the left and once on the right, without any load.
6.1.3.2 Slewing torque test
The rotary test is carried out at 15 r/min at the rated working pressure for each interface. The torque sensor is connected to the central rotary joint and each interface is rotated in forward and reverse for 2.5 min.
6.2 Pneumatic line test
6.2.1 Test preparation
6.2.1.1 The test shall be carried out on the test bench or on the corresponding load-bearing machine.
6.2.1.2 Compressed air for the test: filtering precision 25 um~50 u.m, water separation efficiency not less than 80%.
6.2.1.3 Air test environmental conditions: ambient temperature 20 ℃ ± 5 ℃; ambient relative humidity of not more than 85%.
6.2.1.4 The accuracy level of the gas circuit measurement and the system error allowed by the measuring instrument for the test is shown in Table 4.
7 Inspection rules
7.1 Factory inspection
7.1.1 The central rotary joint shall be inspected by the factory before leaving the factory.
7.1.2 See Table 6 for factory inspection items.
7.2 Type inspection
7.2.1 Type inspection means a comprehensive assessment of product quality, i.e. a comprehensive inspection according to the technical requirements specified in the standard. Where one of the following circumstances, the type test should be carried out:
a) new products or old products transferred to the production of prototype identification
b) when the normal production process, such as structure, materials or processes have changed significantly, and may affect the performance of the product
c) after a long hiatus, when resuming production.
7.2.2 type test items see Table 6.
8 Marking. Packaging and transport
8.1 Marking
8.1.1 Product labeling should comply with the provisions of GB/T 13306.
8.1.2 Product labeling should include the following:
a) the name and address of the manufacturer;
b) Product name and model number
c) Rated pressure (MPa);
d) rated flow rate (mL/ min);
e) Number of channels
f) Year of manufacture or factory number;
g) Standard number.
8.1.3 Before leaving the factory, the central reversing coupling shall be clearly marked with a symbol indicating the function of the interface in the vicinity of all interfaces.
8.2 Packaging and transport
8.2.1 The central rotary joint shall be securely packed and protected against vibration and rust.
8.2.2 The following documents shall be provided in the packing box:
a) Product certificate of conformity;
b) Instructions for use of the product;
c) Packing list.
8.2.3 Each interface should be sealed with an oil plug and the exposed machining surface should be coated with anti-rust oil.
8.2.4 The box size and weight of the central rotary joint shall conform to the regulations of the railway, road and river transport authorities.
Appendix A (informative) Central swivel joint hydraulic line durability test bench test circuit schematic
1 Scope
2 Normative references
3 Terms and definitions
4 Marking
5 Technical requirements
6 Test methods
7 Inspection rules
8 Marking. Packaging and transport
Appendix A (informative) Central swivel joint hydraulic line durability test bench test circuit schematic
