The intensity that passes through the coils depends on the impedance (resistance) of the winding as well as the supply voltage.
The role of the main pressure limiter is to protect the pump from overpressure.
The role of the main pressure limiter is to protect the pump from overpressure.
The pump generates a flow that must be directed at all times:
- To the hydraulic receivers.
- To the tank using a directional valve.
- To the tank using a pressure relief valve.
The Rexroth "A4V" pump is a variable displacement piston pump that can be used in open circuit (A4VSO) and loop circuit (A4VSG).
Relative pressure : the pressure read on the pressure gauges in the hydraulic circuits.
Atmospheric pressure : Pressure exerted by the air on the earth's surface (about 1 bar).
Absolute pressure: It is the addition of the relative pressure and the atmospheric pressure (total pressures).
The role of the pressure reducing valve is to protect a part of the hydraulic circuit by reducing the pressure.
Some examples:
- Protect the brake of a hydraulic motor.
- Provide reduced pressure to hydraulic joystick controls.
- Reduce the pressure of a control circuit.
The role of the pressure reducing valve is to protect a part of the hydraulic circuit by reducing the pressure.
Some examples:
- Protect the brake of a hydraulic motor.
- Provide reduced pressure to hydraulic joystick controls.
- Reduce the pressure of a control circuit.
In the hydraulic diagram, the pressure relief valve is located between the pump and the distributor.
The assembly is sandwiched between a manifold block and a directional valve. Four O-rings will seal between each slice and will be assembled with four screws
In hydraulic circuits, the same component can be called choke, flow restrictor or flow limiter.
The role of the flow limiter is to reduce the speed of the receivers (jacks or motors).
The specification states to size a hydraulic circuit to operate a press cylinder.
We have a double-acting cylinder with a length of 30cm. The diameter of the piston is 160mm and the diameter of the rod is 80mm.
sheet explaining the operation of the 2-way flow regulator
The flow regulator keeps a constant flow regardless of the load of the receiver.
There are two types of flow regulator:
- 2-way flow regulator.
- 3-way flow regulator.
In hydraulics, the directional valve's role is to direct the oil towards the receivers. It can be "all or nothing" or proportional.
The pilot order can be:
- Electric.
- Mechanical by lever or cable.
- Hydraulic.
- Pneumatic.
There are 2 types of directional valves:
- A poppet valve: They have the distinction of being waterproof. On the other hand, their number of positions remain limited.
- With spools: They can be 3/2 - 4/3 - 6/3 ... On the other hand they are not waterproof.
The above directional valve is a Cetup type mounting (ISO standard).
It is mounted on a drilled block and assembled with 4 screws. The seal between the drilled block and the distributor is provided by 4 O-rings.
The directional valves make it possible to direct the oil towards the receivers.
We distinguish 2 large families
- Poppet: the advantage of this type of directional valve is to be sealed internally when closed.
- Spool : the advantage of this type of dispenser is to have a greater number of positions.
The loop circuit will be reserved for rotary movements (motors). In very rare cases to linear movements. (Marine for example).
Also called hydrostatic circuit, it is mainly found on mobile machines (public works, agriculture, forestry, marine, etc.)
The role of the jacks is to transform hydraulic energy into linear force.
There are 2 modes of action:
- Single acting cylinders.
- Double acting cylinders.