Electric Pump


Many off-highway vehicles are required to incorporate supplementarysteering and braking in the event of engine failure deactivating the primarysteering system. Traditional methods incorporate a bi-directional pump drivenoff the transmission, which continues to provide flow as long as the vehicle ismoving. This is an expensive solution since it requires an extra mounting padon the transmission or a mechanical linkage from the transmission to the pump.Some systems require a clutch which adds further complexity. In addition thepump has to be large enough to provide the required flow at low speeds.

We were the first to introduce electro-hydraulic systems for thesteering function and have now developed products that combine bothsupplementary steering and braking. The electro-hydraulic solution replacesexpensive mounting pads and mechanical interfaces with wires. It also allowsthe use of a smaller uni-directional pump. Concentric excels in the specialisttechnology of integrating DC motors, hydraulic pumps and valves. Theelectro-hydraulic unit is required to operate in a very harsh environment forwhich Concentric's DC motor/pump units, such as the the IP 67 sealed motor,heavy-duty start switches and insulated wiring boots are all ideally suited.


-       Long life

-       High efficiency

-       Heavy Duty

-       Silent operation

-       Great reliability

-       Low level of cogging


Nominal power

-         1 - 4 kW

Nominal voltage

-         12 V , 24V


-         2000 min-1

Maximal torque

-         10 Nm (upon demand)

Maximal cogging

-         16 Nm


Eletro-Hydraulics Actuator (EHAs)

  Electro-hydraulicactuators (EHAs), replace hydraulic systems with self-containedactuators operated solely by electrical power. EHAs eliminate the need forseparate hydraulic pumps and tubing, simplifying system architectures andimproving safety and reliability. This technology originally was developed forthe aerospace industry but has since expanded into many other industries wherehydraulic power is commonly used.

 The primary development thatlead to the possibility of EHAs was the precision feedback controlledconventional motor, or high-power stepper motor.[3] Steppermotors are designed to move a fixed angle with every application of energy, anddo so repeatedly in an extremely precise fashion. Both types of motor driveshave been in use for years, powering the controls on motioncontrol rigs and numericcontrol machine tools for instance.

With an EHA, high-power versions of these motors are used to drive areversible pump, which is tied to a hydraulic cylinder. The pump pressurizes aworking fluid, typically hydraulic oil, directly raising the pressure in thecylinder, and causing it to move. The entire system, consisting of the pump,the cylinder and a reservoir of hydraulic fluid, is packaged into a singleself-contained unit.

Instead of the energy needed to move the controls being supplied byan external hydraulic supply, it is supplied over normal electrical wiring,albeit larger wiring than what would be found in a fly-by-wire system. Thespeed of the motion is controlled through the use of pulse-code modulation. The result is a"power-by-wire" system, where both the control and energy are sentthrough a single set of wires.

Redundancy can thus be provided by using two such units per surface,and two sets of electrical wires. This is far simpler than the correspondingsystems using an external hydraulic supply. Additionally, the EHA has theadvantage that it only draws power when it is being moved, the pressure ismaintained internally when the motor stops. This can reduce power use on theaircraft by eliminating the constant draw of the hydraulic pumps. EHAs alsoreduces weight, allow better streamlining due to reduced internal routing ofpiping, and lower overall weight of the control system.


Cooling Fan Drive Systems

Hydraulic fan drive systems offer greater cooling control becausethey are independent of engine speed. For the same reason, they are quieterthan conventional systems and offer greater flexibility to vehicle systemdesigners. Fuel economy is enhanced by providing cooling on demand. Concentricoffers a complete selection of fan drive systems for off-road vehicles.


Agricultural Equipment Rotary Drive Systems

Agriculturalequipment such as combines, seeders, planters and sprayers utilize Concentrichydraulic motors on rotary drive systems for applications such as the chaffseparator, air separator, blower and vacuum. Each vehicle application hasdifferent dynamics that impact the requirements for the hydraulic motor.Application requirements include high volumetric efficiency, high speed, zeroleak, the ability to handle pressure spikes and long life in a harshenvironment. Concentric engineers understand how the vehicle system dynamicsimpact the performance of a hydraulic motor and work very closely withcustomers to fine-tune the performance of their hydraulic motors to thespecific vehicle dynamics.