HST HST
Integrated HST (Pump and Motor)
HST stands for Hydrostatic Transmission and is used in a travel system to connect the hydraulic pump with the motor in a closed Integrated HST enables an easy combination of a speed reducer and a transmission. This unit is designed to meet the vehicle
circuit enabling continuous speed change from Forward to Stop/Neutral and Reverse or vice versa. HST is smoother in operation travel requirements for tractors, combine harvesters, snowplows, etc.
and smaller in size than mechanical transmissions installed on automobiles. It can be combined with electronic control or servo functions.
■ HVFD Series
Integrated HST (Pump & Motor)
Basic Construction
● HVFD18F-R35 Circuit example
HVFD28V37
Basic Characteristics
■ Output Horsepower characteristic ■ Output Speed ■ Output torque
characteristics characteristic
※ The direction of rotation of the pump input shaft can be set in either the CW or CCW direction for HVFD10 Series only. Please specify the
type: either CW (clockwise) or CCW (counterclockwise) for another series, when ordering.
【Light and Heavy duty Models】
● Light duty models: Suitable for the travel system of vehicles that serve light load work such as lawn mowers and combine
harvesters, up to 18kw or smaller.
● Heavy duty models: Suitable for the travel system of vehicles that serve moderate load work such as tractors and combine
harvesters with engine horsepower of 18 to 59kw.
① Theoretical output speed: (Pump displacement)/(motor displacement) × (Input speed)
② Actual speed: (Theoretical output speed) × (Volumetric efficiency)
③ Theoretical output torque: (Motor displacement) × (HST load pressure)
Main Mechanism
■ Servo Regulator 【Neutral mechanism】
■ Servo Regulator (Manual Operation) [SL] (Electric Control) [EL] ● Orifice
Lever operation torque characteristic Ampere - Output speed Standard neutral mechanism allowing a relatively large neutral width.
● Movable thrust plate
HVFD37F-R35-SL example characteristics This method is less affected by the given conditions such as the input speed and oil temperature, allowing a stable neutral
width. This is superior to the orifice method in neutral zone stability and adjustability of the neutral point.
【Option】
● Charge pump
When the charge pump is used together with an oil hydraulic unit installed on the vehicle, select the charge pump
displacement approximately 25% of the HST pump.
● Servo regulator
This component features the following advantages:
◇ Low operation torque allowing an easy operation and lower noise caused by link vibrations.
◇ Good responsiveness and a stable neutral characteristic.
◇ The fail-safe mechanism is included as a standard accessory for automatic return to the neutral
position in case of a hydraulic power source failure or link connection failure.
◇ Can be mounted on to a manual type HST.
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HST HST
Integrated HST (Pump and Motor)
HST stands for Hydrostatic Transmission and is used in a travel system to connect the hydraulic pump with the motor in a closed Integrated HST enables an easy combination of a speed reducer and a transmission. This unit is designed to meet the vehicle
circuit enabling continuous speed change from Forward to Stop/Neutral and Reverse or vice versa. HST is smoother in operation travel requirements for tractors, combine harvesters, snowplows, etc.
and smaller in size than mechanical transmissions installed on automobiles. It can be combined with electronic control or servo functions.
■ HVFD Series
Integrated HST (Pump & Motor)
Basic Construction
● HVFD18F-R35 Circuit example
HVFD28V37
Basic Characteristics
■ Output Horsepower characteristic ■ Output Speed ■ Output torque
characteristics characteristic
※ The direction of rotation of the pump input shaft can be set in either the CW or CCW direction for HVFD10 Series only. Please specify the
type: either CW (clockwise) or CCW (counterclockwise) for another series, when ordering.
【Light and Heavy duty Models】
● Light duty models: Suitable for the travel system of vehicles that serve light load work such as lawn mowers and combine
harvesters, up to 18kw or smaller.
● Heavy duty models: Suitable for the travel system of vehicles that serve moderate load work such as tractors and combine
harvesters with engine horsepower of 18 to 59kw.
① Theoretical output speed: (Pump displacement)/(motor displacement) × (Input speed)
② Actual speed: (Theoretical output speed) × (Volumetric efficiency)
③ Theoretical output torque: (Motor displacement) × (HST load pressure)
Main Mechanism
■ Servo Regulator 【Neutral mechanism】
■ Servo Regulator (Manual Operation) [SL] (Electric Control) [EL] ● Orifice
Lever operation torque characteristic Ampere - Output speed Standard neutral mechanism allowing a relatively large neutral width.
● Movable thrust plate
HVFD37F-R35-SL example characteristics This method is less affected by the given conditions such as the input speed and oil temperature, allowing a stable neutral
width. This is superior to the orifice method in neutral zone stability and adjustability of the neutral point.
【Option】
● Charge pump
When the charge pump is used together with an oil hydraulic unit installed on the vehicle, select the charge pump
displacement approximately 25% of the HST pump.
● Servo regulator
This component features the following advantages:
◇ Low operation torque allowing an easy operation and lower noise caused by link vibrations.
◇ Good responsiveness and a stable neutral characteristic.
◇ The fail-safe mechanism is included as a standard accessory for automatic return to the neutral
position in case of a hydraulic power source failure or link connection failure.
◇ Can be mounted on to a manual type HST.
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HST HST
Dimensions (unit: mm)
■ HVFD23F
■ HVFD10F
Hydraulic circuit
Hydraulic circuit
■ HVFD18F ■ HVFD28F
Hydraulic circuit
Hydraulic circuit
■ HVFD21F ■ HVFD37F
Hydraulic circuit
Hydraulic circuit
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HST HST
Dimensions (unit: mm)
■ HVFD23F
■ HVFD10F
Hydraulic circuit
Hydraulic circuit
■ HVFD18F ■ HVFD28F
Hydraulic circuit
Hydraulic circuit
■ HVFD21F ■ HVFD37F
Hydraulic circuit
Hydraulic circuit
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HST HST
■ HVFD28V37 (two-speed) Performance Curve Operating oil: ISOVG46 Oil temperature: 50℃
<HST: Light load model>
■ HVFD10F-N15,N18 ■ HVFD21F-R18,R23
Hydraulic circuit
<HST: Heavy load model>
■ HVFD18F-R35 ■ HVFD23F-R35
■ HVFD37V50 (two-speed)
Hydraulic circuit
■ HVFD28F-R35 ■ HVFD37F-R35
<HST: Two-speed motor type>
■ HVFD28V37-R35 ■ HVFD37V50-R35
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HST HST
■ HVFD28V37 (two-speed) Performance Curve Operating oil: ISOVG46 Oil temperature: 50℃
<HST: Light load model>
■ HVFD10F-N15,N18 ■ HVFD21F-R18,R23
Hydraulic circuit
<HST: Heavy load model>
■ HVFD18F-R35 ■ HVFD23F-R35
■ HVFD37V50 (two-speed)
Hydraulic circuit
■ HVFD28F-R35 ■ HVFD37F-R35
<HST: Two-speed motor type>
■ HVFD28V37-R35 ■ HVFD37V50-R35
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