Cat.I-Edit1EISERVO VALVES
Maximum
OperatingPressureMPa

Valve Type

High-Speed Linear
Servo Valves

35

LSVG－03 4TwoStage
Type35900：35
1300：31.5

LSVHG－04

OBE Type Linear
Servo Valves(High PerformanceType)TwoStage
TypeTwoStageType■ Linear Servo Amplifier(Valve Pressure Diﬀerence:7 MPa)

550

2Direct
TypeDirect
Type
OBE Type Linear
Servo Valves(Std. Type)

1

Rated Flow L/min

1020 3020100200 300 500

LSVHG－1035

LSVG－01EH 435

LSVG－03EH

31.5

LSVHG－03EH35

LSVHG－04EH

1000 2000

5000

Page

I-540 60750

LSVHG－06

35900：35
1300：31.5109001300

I-103800
1020I-2240 60

230210270580

LSVHG－06EH35

LSVHG－10EH

31.5

LSVHG－03EH－※－S

60 100 160

35

LSVHG－04EH－※－S

10035

LSVHG－06EH－※－S

7509001300820

I-313800

200 280 450

I-52

500 900

AMLS−＊…………………………………………………………………………………… Page I-19

■ Servo Amplifiers & Controllers

SK1056/AMS−＊………………………………………………………………… Page I-61

I-1

Hydraulic Fluids■ Type of Fluids
Any type of hydraulic fluid listed in the table below can be used.
Petroleum Base Oils

Use fluids equivalent to ISO VG32 or VG46.

Synthetic Fluids

Use phosphate ester or polyol ester type. When phosphate ester type fluid is used, prefix“F-”to the model number because a special seal (fluororubber) will be used.

Water Containing Fluids

Use water-glycol fluids. Water-glycol fluids cannot be used for valves“without Y port”(wet type: LSVG-*EH-*-W) or“without DR port”(wet type pilot valve: LSVHG-*EH-**-W).

Note: For use with hydraulic fluids other than those listed above, please consult your Yuken representatives in advance.

■ Recommended Viscosity and Temperature
Use hydraulic fluids which satisfy both recommended viscosity and oil temperatures given in the table below.
ViscosityTemperature

15 - 400 mm2/s−15 - ＋60 ℃■ Control of Contamination
Keep the hydraulic fluid clean and provide a line filter so that contamination of the fluid will not obstruct proper valve operation. To
assure long life of linear servo valves, it is recommended to improve fluid cleanliness before use.
Contamination LevelLine Filter

NAS1638 Class 10

Absolute 20 μmISO4406 21/19/15Instructions■ Mounting
Mount the valve with the angle of the axis line L-L' within about ±15°from the horizontal plane, as shown below. The valve must bemounted in such a way that the spool axis direction is not matched with the main vibration direction; otherwise, an external force may
cause the spool to malfunction.

＋15°

L’L－15°L’－15°

I-2L’
－15°

＋15°
0 404

L＋15°

L＋15°

L

L’－15°High Speed Linear Servo Valves/OBE Type Linear Servo ValvesLinear Servo Valves■ Installation Requirements
Avoid installing the valve in a strong magnetic field. Especially, the position sensor for detecting the spool position is affected by themagnetic field. Keep the valve away from devices that generate magnetic fields, such as solenoid operated directional valves. At thesame time, a magnetic field generated by the valve may affect other devices; any device vulnerable to magnetic fields must not be
installed near the valve.

■ Drain Piping (LSVG: Y Port/LSVHG: DR Port)
LSVG/LSVHG series high speed linear servo valves have a diaphragm mechanism that keeps the inside of the linear motor dry in order
to meet the requirements below.
1)	Keeping response characteristics almost unchanged when fluid viscosity varies (the response characteristics of existing proportional/
servo valves vary with changes in fluid viscosity).
2) Protecting moving coils from iron powder or moisture in hydraulic fluids.
A special drain port is provided to define the upper limit of pressure for the diaphragm, if any, so that the valve performance ismaintained. For valve installation, provide a drain line by taking into account the following piping considerations.
①Back pressure at the drain port should be 0.05 MPa or less and not be a negative pressure.
②The drain line should be open to the air (the line end must not contact the fluid).
★There are two types of pilot valves available: a dry type good in response characteristics
and a wet type that eliminates the Y or DR port to improve usability.
Moving Coil■ Cable Length for I/O Signals
1) High speed linear servo valves (amplifier-separated type)Use a cable of up to 30 m in length.
Consult us for customized products (Model: LSVG-03/LSVHG-04, 06) that allow theuse of a cable of up to 200 m in length.
2) OBE (on-board electronics) type liner servo valves
The maximum cable length depends on the I/O signal type. See the table below.
I/O Signal Type

Valve Model Number

Max. Cable Length±10 V

LSV（H）G−＊＊EH−＊＊−＊−＊−A＊/D＊−1050 m★

4 - 20 mA

LSV（H）G−＊＊EH−＊＊−＊−＊−B＊/E＊−10±10 mA

LSV（H）G−＊＊EH−＊＊−＊−＊−C＊/F＊−10Drain Line

Diaphragm

Permanent Magnet

Structure of the Linear Motor300 m★Consult us when the cable length exceeds 50 m.
For both valve types in 1) and 2), pay attention to ensure that the power cable resistance is within 1 Ω and is as low as possible.

■ Electrical Failure and Safety Measures for Startup
Provide a separate safety circuit (e.g. uninterruptible power supply), if required, to securely continue/stop the operation of the hydraulicactuator for safety in case of electrical failure (power failure, cable disconnection, etc.) or upon startup.

■ Supply Pressure
The servo valves are designed to operate at constant supply pressure; variations in supply pressure should be avoided as much as possible.
Especially, for systems requiring high accuracy, the circuit must be designed to keep the supply pressure constant.
Ideally, an accumulator will be installed in the supply pressure line near the servo valve to avoid supply pressure fluctuations during
pressure transients.

■ Pressure at the Return PortThe return port of the servo valve may be subject to a considerably high pressure depending on the circuit type. However, it should beused at atmospheric pressure or similar pressure as much as possible. The pressure at the return port should be equal to or below actual
supply pressure.

■ Disassembly/ReassemblyLinear servo valves consist of highprecision components. You are prohibited from disassembling or reassembling the valves; otherwise,Diaphragmthe designed valve performance may be degraded.

High Speed Linear Servo Valves/OBE Type Linear Servo Valves

I-3

Valve Pressure Difference/Load Pressure DifferenceThis catalog uses two terms related to pressure differences:“valve pressure difference”(used for the range of flow control and no-loadflow characteristics) and“load pressure difference”(used for load flow characteristics). The terms are described below.

Load■ Valve Pressure Difference
Suppose that, in the circuit shown on the right, the fluid flows from P to A and from B to T. In this case,the sum of the pressure differences between P and A and between B and T is the pressure difference of this valve.
For this four-way valve, the valve pressure difference“ΔP”is:Valve Pressure Difference = [(Pres. at P) - (Pres. at A)] + [(Pres. at B) - (Pres. at T)].
In relation to the flow rate, an increase in the flow through the valve with a constant valve opening leads to anincrease in the valve pressure difference due to increased flow resistance at the control part.

■ Load Pressure Difference
In the circuit above, the absolute pressure difference between A and B is the load pressure difference.
Load Pressure Difference = ¦ (Pres. at A) - (Pres. at B) ¦If the resistance of piping, etc. is ignored, the difference between the supply pressure and the load pressure difference is the valvepressure difference of the linear servo valve. Therefore, a smaller load pressure difference means a larger valve pressure difference,
allowing increasing the flow rate through the valve.

Flow Rate
In this catalog, the rated flow tolerance is ±10 %The flow rate depends on the viscosity and specific gravity of each hydraulic fluid.
● Multiply each viscosity by the corresponding coefficient in the table below.
Viscosity mm2/s

152030

40

50

60

70

80

90

100

Coefficient

1.19

1.11

1.00

0.93

0.88

0.84

0.81

0.78

0.76

0.74

● Use the following formula to obtain the ﬂow rate corresponding to a speciﬁc gravity. Q’＝ Q （ 0.85／G’）● Use the following formula to obtain the relationship between the ﬂow rate and the pressure for a servo valve.
QX = Qrate ΔPX
7whereI-4

QX : Flow rate to be determined;
Qrate : Rated ﬂow rate (at ΔP = 7 MPa); andΔPX : Valve pressure diﬀerence in the actual circuit.

High Speed Linear Servo Valves/OBE Type Linear Servo Valves