FluidPower.Pro

Author Archive: Dzyanis

Rexroth A4VG clones

Just in case if you need replacement for Rexroth A4VG, it seems to me these guys are brothers:

Rexroth A4VG Parker C-series Dana Brevini S6CV
Rexroth A4VG Parker C-series Dana Brevini S6CV
Available Displacements:
28cc, 40cc, 56cc, 71cc, 90cc, 125cc 55cc, 81cc, 136cc 75cc, 128cc
Nominal pressure:
400 bar (5800 psi) 420 bar (6090 psi) 400 bar (5800 psi)
Input Speed, Continuous:
400 bar (5800 psi) 420 bar (6090 psi) 400 bar (5800 psi)
Available control systems:
HD” Proportional control, hydraulic C” Hydraulic proportional control with internal feedback HIR” Hydraulic proportional with feed-back
EP” Proportional control, electric F” Electric proportional with internal feedback HER” Electric proportional with feed-back
ET” Electric control, direct operated, two pressure reducing valves G” Electric proportional without internal feedback HEN” Electric proportional without feed-back
EZ” Two-point control, electric E” Electric non proportional HE2” Electric on-off
DG” Hydraulic control, direct operated D” Hydraulic proportional control without internal feedback HIN” Hydraulic proportional without feed-back
– – – A” Manual lever HLR” Manual lever with feed-back

Semi-closed hydraulic circuits

Have you ever heard about the semi-closed hydraulic circuit?

The idea is to use open loop pumps in closed loop circuit. In the latest eighties, Mannesmann Rexroth (yes, that time Mannesmann yet!) even offered pumps A4VSH, especially designed for semi-closed circuits.

Bosch Rexroth A4VSH pump

Bosch Rexroth A4VSH pump, from catalog RE92110/01.89

The main difference between closed loop pumps and semi-closed loop pumps was in addition block mounted to the ports A and B with check valves which let to supply suction flow from the tank, while mainstream comes from the motor to pump’s suction port:

Since that time Rexroth still builds A4VSH, but there are a limited number of sizes and options available and its no longer a mainstream published option.

But to make a semi-closed loop you do not need some special pump, it’s really easy to turn most standard open loop pump into a semi-closed loop circuit. Of course, you have to have some knowledge about the application and actuators before trying to apply it. If the pump does not have an integrated boost pump and check valves these are commonly added via an external gear pump and external check valves.

Here is the simplest example of the semi-closed circuit schematic where a regular open loop pump with LS control is involved to run two motors with independent proportional control of their speeds:

Technicien hydraulique

Title: Technicien hydraulique
Location: Saint-Bruno, QC, Canada
Employer: MCS-Servo
Job Type: Full-time, Permanent

Titre : Technicien hydraulique

Sous l’autorité du : Directeur(trice) de fabrication et réparation

Assemblage/usinage/soudage – 60%

  • Classer le matériel reçu selon les projets et assemblages à effectuer
  • Prendre de l’inventaire les pièces selon le bon de matériel
  • Élaborer, planifier et optimiser la position de certaines composantes afin de former des sous-ensembles ou des produits finis (vérins hydrauliques, unités de puissance hydrauliques, blocs forés ou autres)
  • Monter, prendre les dimensions, ajuster et installer les pièces préfabriquées afin de former des sous-ensembles ou des produits finis selon les dessins, schémas, procédures, normes, tables et autres documents pertinents. Production pouvant aller à 50 unités plusieurs fois par année.
  • Noter les ajouts et retraits des pièces requises, les quantités utilisées et remettre le bon de matériel mis à jour au directeur de fabrication et réparation une fois le montage terminé et testé
  • Identifier les composantes à l’aide de plaques signalétiques selon la numérotation établie
  • Noter les numéros de série
  • Placer, couper, tarauder, aligner et ajuster les pièces afin qu’elles soient bien ajustées et montées et joindre des tubes et des boyaux
  • Fixer les pièces à l’aide de matériel de boulonnage, par soudage ou en utilisant d’autres méthodes de fixation et d’assemblage
  • Usiner certaines pièces requises pour les sous-ensembles
  • Fabriquer des tubes hydrauliques évasés, des boyaux hydrauliques pressés et des tiges de retient filetées
  • Peinturer au pistolet les pièces, sous-ensembles et produits finis
  • Opérer un chariot élévateur afin de déplacer et de mettre en place les pièces
  • Vérifier, ajuster aux valeurs prédéterminées et tester les sous-ensembles et les produits finis afin d’assurer un fonctionnement adéquat et d’assurer leur conformité aux normes de qualité établies
  • Faire des ajustements mineurs et des corrections, s’il y a lieu

Hydraulic Specialist – Cylinders

Title: Hydraulic Specialist – Cylinders
Location: Prince George, BC, Canada
Employer: Finning International Inc.
Job Type: Full-time, Permanent

Join the Finning Canada family, part of the world’s largest Caterpillar dealer. We are currently looking for a dedicated Hydraulic Specialist who will be responsible for the assembly and disassembly of cylinders on a variety of Caterpillar general line products, based in Prince George. You will be responsible and involved in all aspects of hydraulic cylinder rebuild and repair.

If you are a safety conscious team player, self-motivated, detail-oriented, have a mechanical aptitude and a valid driver’s license, then you are exactly who we are looking for!

Job Description:

  • Disassemble, assemble, rebuild and repair all sizes of hydraulic cylinders
  • Work with large machinery and tooling to facilitate rebuilds
  • Troubleshooting and problem solving with heavy equipment

Qualifications: