GB/T 13854-2025 Jet-pipe electro-hydraulic servo valve English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 47.020.30 CCS U 57
GB/T 13854-2025 replaces GB/T 13854-2008
Jet-pipe electro-hydraulic servo valve
Issued on 2025-08-29; Implemented on 2026-03-01
Issued by the State Administration for Market Regulation and the Standardization Administration of China
Contents
Foreword
1 Scope
2 Normative references
3 Terms, definitions, and symbols
4 Classification
5 Requirements
6 Test methods
7 Inspection rules
8 Marking, packaging, transportation, and storage
Jet-pipe electro-hydraulic servo valve
1 Scope
This document specifies the classification, requirements, inspection rules, marking, packaging, transportation, and storage of jet-pipe electro-hydraulic servo valves (hereinafter referred to as servo valves), and describes the corresponding test methods.
This document applies to the design, manufacture, and inspection of various types of jet-pipe flow control electro-hydraulic servo valves using hydraulic oil as the medium. Other types of jet-pipe electro-hydraulic servo valves may also reference this document.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute essential provisions of this document. For dated references, only the editions cited apply. For undated references, the latest edition (including any amendments) applies.
GB/T 2423.4-2008 Environmental testing for electrical and electronic products-Part 2: Test methods-Test Db: Damp heat, cyclic (12 h + 12 h cycle)
GB/T 2423.5-2019 Environmental testing-Part 2: Test methods-Test Ea and guidance: Shock
GB/T 2423.16-2022 Environmental testing-Part 2: Test methods-Test J and guidance: Long-term mold
GB/T 2423.17-2024 Environmental testing-Part 2: Test methods-Test Ka: Salt spray
GB/T 2423.48-2018 Environmental testing-Part 2: Test methods-Test Ff: Vibration-Time history and sine beat method
GB/T 2423.63-2019 Environmental testing-Part 2: Test methods-Test: Temperature (low temperature, high temperature)/low pressure/vibration (mixed mode) combination
GB/T 2423.65-2024 Environmental testing-Part 2: Test methods-Test: Salt spray/temperature/humidity/solar radiation combination
GB/T 3141-1994 Industrial liquid lubricants-ISO viscosity classification
GB/T 13384-2008 General technical requirements for packaging of mechanical and electrical products
GB/T 14039-2002 Hydraulic fluid power-Fluids-Designation of solid particle contamination levels
GB/T 17446-2024 Fluid power systems and components-Vocabulary
GB/T 17799.4-2022 Electromagnetic compatibility-Generic standards-Part 4: Industrial environment emissions
GB/T 20082-2006 Hydraulic fluid power-Fluid cleanliness-Method for determining particulate contamination by optical microscopy
3 Terms, definitions, and symbols
3.1 Terms and definitions
Terms and definitions established in GB/T 17446-2024, as well as the following, apply to this document.
3.1.1
Jet-pipe electro-hydraulic servo valve
An electro-hydraulic servo valve with a jet pipe as the preamplifier stage.
3.1.2
Pressure gain
The rate of change of load pressure drop with respect to input current when the control flow is zero.
Note: The pressure gain curve is shown in Figure 1.
Figure 1 Pressure gain curve
3.1.3
Null
The relative geometric position of the output stage when the load pressure drop is zero and the control flow is zero.
3.1.4
Null region
The region near the null where the flow gain is affected by parameters such as overlap and internal leakage.
3.1.5
Threshold
The minimum increment of input current required to cause a change in the output flow of the servo valve.
Note: Expressed as a percentage of the rated current. The threshold curve is shown in Figure 2.
Figure 2 Threshold curve
3.1.6
Null shift
The change in null bias due to variations in working conditions such as pressure and temperature.
Note: The null shift is expressed as a percentage of the rated current.
3.1.7
Internal leakage
The internal flow from the inlet port to the outlet port when the control flow of the servo valve is zero.
Note: It varies with inlet pressure and input current (see Figure 3).
Figure 3 Internal leakage curve
3.1.8
Control flow
The flow from the control ports (A or B) of the servo valve.
Note: The control flow when the load pressure drop is zero is called no-load flow, and the control flow when the load pressure drop is not zero is called load flow (see Figure 4).
Figure 4 Control flow curve
3.1.9
No-load flow curve
The continuous curve obtained by making a complete cycle of no-load control flow as the input current varies between positive and negative rated current.
3.1.10
Rated flow rate
The no-load flow of the servo valve at the rated supply pressure and corresponding to the rated current.
3.1.11
Normal flow curve
The trajectory of the midpoint of the complete cycle flow curve.
3.1.12
Flow gain
The slope of the flow curve within the specified operating region.
Note: Expressed in L/(min·mA). Flow control servo valves are typically divided into three operating regions: null region, normal flow control region, and saturation region (see Figure 5). Unless otherwise specified, this term refers to the normal flow gain.
Figure 5 Operating regions
3.1.13
Normal flow gain
The normal flow gain line is obtained by drawing a straight line with the minimum deviation from the normal flow curve from the zero flow point of the normal flow curve in both polarities.
Note: The flow gain curve is shown in Figure 6.
Figure 6 Flow gain, linearity, and symmetry
3.1.14
Linearity
The linearity of the normal flow curve.
Note: Measured by the maximum deviation between the normal flow curve and the normal flow gain line, expressed as a percentage of the rated current (see Figure 6).
3.1.15
Symmetry
The degree to which the normal flow gains of the two polarities are consistent.
Note: Expressed as the percentage difference between the two, relative to the larger value (see Figure 6).
3.1.16
Hysteresis
The maximum difference between the input current for the same output when cycling between positive and negative rated current at a speed less than the dynamic characteristics of the test equipment.
Note: Hysteresis is expressed as a percentage of the rated current (see Figure 4).
3.1.17
Lap
The relative axial position between the fixed metering edge and the movable metering edge when the spool is at null.
Note: For servo valves, the lap is measured by extending the normal flow curve for each polarity to approximate the straight-line portion. The total interval between the zero flow points of the two extensions is the lap, expressed as a percentage of the rated current.
3.1.18
Zero lap
The absence of any lap between the zero flow points of the normal flow curves for the two polarities.
