Note

• Safety requirements pertaining to the whole systems are to be observed.

• Please contact us for applications with frequent load changes.

Note

You can find diagrams for a rough calculation in chapter "Diagrams / Characteristic curves".

Hydraulic fluids

The external gear unit is designed for operation with mineral oil according to DIN 51524, 1-3. Under higher load, however, Bosch Rexroth recommends at least HLP compliant with DIN 51524 Part 2.

Application instructions and requirements for hydraulic fluids should be taken from the following data sheets before the start of project planning:

• 90220: Hydraulic fluids based on mineral oils and related hydrocarbons

 

Other hydraulic fluids on request.

Explanatory note regarding the selection of hydraulic fluid

The hydraulic fluid should be selected such that the operating viscosity in the operating temperature range is within the optimum range (v_opt see selection diagram).

Observe the instructions for the filtration of the hydraulic fluid (see chapter Project planning information).

 

Direction of rotation

The dimensional drawings in the chapter Dimensions represent pumps for clockwise rotation. The position of the drive shaft or the position of suction and pressure port changes for counter-clockwise rotation.

Drives

1. Elastic couplings

• The coupling must not transfer any radial and axial forces onto the pump.

• The maximum admissible radial run-out deviation from the shaft to the fitting slot is 0.2 mm.

• Admissible shaft shifting see installation information of the coupling manufacturers.

2. Coupling sleeve

• To be used on splined shaft profile according to DIN and SAE.

• Attention: No radial or axial forces are permitted on the pump shaft or coupling sleeve. The coupling sleeve must be free to move axially.

• The distance between the pump drive shaft and drive shaft on the customer side must 3,5^+1,5 mm.

• Provide installation space for the snap ring.

• Oil-bath or oil-mist lubrication is required.

3. Coupling claw

• For direct attachment of the pump at electric or combustion motor, gears, etc.

• Pump drive shaft with special coupling claw and driver (3)

• No shaft sealing

• Installation on drive side and sealing according to the following recommendations and dimensions

• Customer-side drive shaft (1)

• Case-hardened steel DIN EN 10084, e.g. 20MnCrS5 case-hardened 1.0 mm deep; HRA 83^±2

• Seal ring sliding surface ground without twist R_max ≤ 4 μm

• Customer-side radial shaft seal ring (2)

• Provide with rubber sheathing (see DIN 3760, form AS, or double-lip ring)

• Provide installation edges with 15° incline and/or assemble shaft seal ring with protective sleeve

4. V-belts and straight gear wheels or helical toothed gear drives without outboard bearing

For V-belt or gear wheel drives, please contact us specifying the application and mounting conditions (dimensions a, d_m, d_w and angle α). For helical toothed gear drives, details of the helix angle β are also required.

5. Outboard bearing

Outboard bearing are offered to eliminate possible problems when the pumps are driven by V-belts or gear wheels. The diagrams show the radial and axial load capacity in relation to a bearing service life of L_H = 1000 h.

Maximum transferable drive torques

Multiple gear pumps

Gear pumps are well-suited to multiple arrangements, whereby the drive shaft of the first pump stage is extended to a second and possibly third pump stage. The shaft of the individual pump sections are normally connected via a driver.

In most cases, each pump stage is hydraulically isolated from its neighbor and the suction ports are separate from one another. On request a common suction port or separated but hydraulically connected suction ports are available.

Note

Basically, the parameters of the single pumps apply, however certain restrictions need to be observed:

• Maximum rotational speed: This is determined by the largest pump stage used.

• Pressures: These are restricted by the maximum transmissible torques of the drive shaft, the through drive and the driver.

Addition of drive torques

Please note, that in multiple pump arrangements the drive torques of the single pumps stages will add up according to the following formula:

This may results in pressure restrictions in the relevant pump stages.

Standard through-drive (coupling dog)

In the case of pumps on platform G, the driver for the following pump stage can be loaded up to M_max = 130 Nm. Possible pressure restrictions must be observed for the following pump stages.

For the following pumps in a smaller series, these determine the maximum transferable torque.

Reinforced through drives

For applications with higher transfer torques or torsional vibrations reinforced through drives up to M_max = 320 Nm are available. Lay out design on request.