Chapter 5 Hydraulic Control Valves Chapter list 5.1 Introduction 5.2 Directional Control Valves 5.3 Pressure Operated Valves 5.4 Flow Control Valves 5.5 Manifold Valves and Cartridge Valves 5.6 Electro-Hydraulic Servo Valves 5.7 Electro-Hydraulic Proportional Valves 5.8 Electro-Hydraulic Digital Valves Homepage List Upwards Dowrwards Retum Exit
Chapter 5 Hydraulic Control Valves 1 5.1 Introduction 5.2 Directional Control Valves 5.3 Pressure Operated Valves 5.4 Flow Control Valves 5.5 Manifold Valves and Cartridge Valves 5.6 Electro-Hydraulic Servo Valves 5.7 Electro-Hydraulic Proportional Valves 5.8 Electro-Hydraulic Digital Valves Chapter list
Chapter 5 Hydraulic Control Valves 5.1 Introduction 5.1.1 Basic characteristics 5.1.2 Classification 5.1.3 Basic requirements for hydraulic valves Homepage List Upwards Downward止s Retumn Exit
Chapter 5 Hydraulic Control Valves 2 5.1 Introduction 5.1.1 Basic characteristics 5.1.2 Classification 5.1.3 Basic requirements for hydraulic valves
Chapter 5 Hydraulic Control Valves 5.1 Introduction The types of control valves used today are too numerous to be mentioned.Most valves,however,perform three primary functions in the hydraulic system:to control the oil pressure (pressure control valves),the flow rate(flow control valves)and the direction of oil flow(directional control valves)in the system to ensure the actuators in proper working on order the load requested. 5.1.1 Basic characteristics Although there are many types of hydraulic control valves and they might be quite different from each other in either the functions or configurations,there exist basic characteristics. Homepage List Upwards Downward达 Return Exit
Chapter 5 Hydraulic Control Valves 3 5.1 Introduction 5.1.1 Basic characteristics The types of control valves used today are too numerous to be mentioned. Most valves, however, perform three primary functionsin the hydraulic system: to control the oil pressure (pressure control valves), the flow rate (flow control valves) and the direction of oil flow (directional control valves) in the system to ensure the actuators in proper working on order the load requested. Although there are many types of hydraulic control valves and they might be quite different from each other in either the functions or configurations, there exist basic characteristics
Chapter 5 Hydraulic Control Valves 1.In structure,all hydraulic control valves consist of the valve body,the valve core(spool,cone or ball)and the operating elements used to control the valve core. The three basic types of cores are shown in Fig.5-1. 2.In operating principle,the orifice flow formula should be kept true for the orifice size,the pressure differences between the inlet and outlet and the flow rate of through the valves. Homepage List Upwards Downwards Retum Exit
Chapter 5 Hydraulic Control Valves 4 1. In structure, all hydraulic control valves consist of the valve body, the valve core (spool, cone or ball) and the operating elements used to control the valve core. The three basic types of cores are shown in Fig.5-1. 2. In operating principle, the orifice flow formula should be kept true for the orifice size, the pressure differences between the inlet and outlet and the flow rate of through the valves
Chapter 5 Hydraulic Control Valves b) c) Fig.5-1 Configuration types a)Spoolvalve b)Cone valve c)Ball valve 5.1.2 Classification The hydraulic control valves can be categorized according to different classification attributes,see Tab.5-1 Homepage List Upwards Downward达s Return Exit
Chapter 5 Hydraulic Control Valves 5 Fig. 5-1 Configuration types a) Spool valve b) Cone valve c) Ball valve 5.1.2 Classification The hydraulic control valves can be categorized according to different classification attributes, see Tab.5-1
Chapter 5 Hydraulic Control Valves Tab.5-1 Classification of hydraulic control valves Classification Contents attributes Types The pressure Relief,pressure reducing,sequence, proportional pressure control,pressure control switch,etc Throttle,speed control,overflow throttle, The functions The flow control dividing,combining,proportional flow control,etc Check,pilot-operated check,directional, The directional proportional direction change,etc control Manually Handle or handwheel,pedal,lever The Skid,spring,hydraulic,pneumatic manipulatio Mechanically n The solenoid-operated,electro-hydraulic Electrically control Homepage List Upwards Downward达 Return Exit
Chapter 5 Hydraulic Control Valves 6 Tab.5-1 Classification of hydraulic control valves Classification attributes Types Contents The functions The pressure control Relief , pressure reducing, sequence, proportional pressure control, pressure switch, etc The flow control Throttle, speed control, overflow throttle, dividing, combining, proportional flow control, etc The directional control Check, pilot-operated check, directional, proportional direction change, etc The manipulatio n Manually Handle or handwheel, pedal, lever Mechanically Skid, spring, hydraulic, pneumatic Electrically The solenoid-operated, electro-hydraulic control
Chapter 5 Hydraulic Control Valves Tab.5-1 Classification of hydraulic control valves The tubing The tubing and the flanged Sub-plate mounting or Single/double-plate mounting, Connection modular integration and sandwich valves The cartridge The screw,and the flanged The constant control The pressure control,the flow valves or switches control,the directional control The electro-hydraulic The electro-hydraulic pressure/flow/directional/combined proportional control valves Control The electro-hydraulic,air-hydraulic, The servo-control mechanical-hydraulic The digital control pressure/flow/ The digital control directional control valves Homepage List Upwards Dowrwards Return Exit
Chapter 5 Hydraulic Control Valves 7 Tab.5-1 Classification of hydraulic control valves Connection The tubing The tubing and the flanged Sub-plate mounting or modular Single/double-plate mounting, integration and sandwich valves The cartridge The screw, and the flanged Control The constant control valves or switches The pressure control, the flow control, the directional control The electro-hydraulic proportional control The electro-hydraulic pressure/flow/directional/combined valves The servo-control The electro-hydraulic, air-hydraulic, mechanical-hydraulic The digital control The digital control pressure/ flow/ directional control valves
Chapter 5 Hydraulic Control Valves 5.1.3 Basic requirements for hydraulic valves 1.Sensitive,credible,and low impact and vibration; 2.Low resistance when the orifice is opened completely, and has good sealing ability when the orifice is closed; 3.Controllable parameters(such as the pressure and the flow rate)should be stable and insensitive under disturbance; 4.Compact in structure and good in installation, adjustment and applications 8 Homepage List Upwards Downwards Return Exit
Chapter 5 Hydraulic Control Valves 8 5.1.3 Basic requirements for hydraulic valves 1. Sensitive, credible, and low impact and vibration; 2. Low resistance when the orifice is opened completely, and has good sealing ability when the orifice is closed; 3. Controllable parameters (such as the pressure and the flow rate) should be stable and insensitive under disturbance; 4. Compact in structure and good in installation, adjustment and applications
Chapter 5 Hydraulic Control Valves 5.2 Directional Control Valves 5.2.1 In-line Check 5.2.2 Directional control valves Homepage List Upwards Dowrwards Retun Exit
Chapter 5 Hydraulic Control Valves 9 5.2 Directional Control Valves 5.2.1 In-line Check 5.2.2 Directional control valves
Chapter 5 Hydraulic Control Valves 5.2 Directional Control Valves There are two types of general directional control valves:in-line check and direction changing. 5.2.1 In-line Check The in-line check valves include:the general type checks and hydraulic operated check valves. 1.The in-line check valves of general type Functions:This valve allows free flow in one direction and prevents flow in the reverse direction Fig.5-2 shows a general type check valve in a threaded pipe connection. 10 Homepage List Upwards Downwards Return Exit
Chapter 5 Hydraulic Control Valves 10 5.2 Directional Control Valves There are two types of general directional control valves: in-line check and direction changing. 5.2.1 In-line Check The in-line check valves include: the general type checks and hydraulic operated check valves. 1. The in-line check valves of general type Functions: This valve allows free flow in one direction and prevents flow in the reverse direction. Fig.5-2 shows a general type check valve in a threaded pipe connection