Radial piston pumps, fixed displacement PR4-3X

Description

• Size 1,60 … 20,00
• Component series 3X
• Maximum operating pressure 700 bar
• Maximum displacement 19.43 cm³

Features

• Fixed displacement
• Self-priming, valve-controlled
• Long service life due to hydro-dynamically lubricated plain bearings
• Several pressure ports with different cylinder combinations
• 14 sizes, favorable grading for perfect device design

Product description

Assembly

The pumps are valve-controlled, self-priming radial piston pumps with fixed displacement.

They consist essentially of the housing (1), eccentric shaft (2) and 3, 5 or 10 pump elements (3), with suction valve (4), pressure valve (5) and piston (6).

Suction and displacement procedure

The pistons (6) are arranged radially to the eccentric shaft (2). The hollow piston (6) with the suction valve (4) is guided in a cylinder (7) and pressed onto the eccentric (2) by the spring (8). The radius of the piston running surface corresponds to the eccentric radius. The cylinder (7) provides sealing against a hemispherical element (9).

In downward movements of the piston (6), the working space (10) in the cylinder (7) is enlarged. Due to the resulting negative overpressure, the suction valve plate is raised from the sealing lip. Simultaneously, the connection from the suction chamber (12) to the working chamber (10) is realized by means of a radial groove (11) in the eccentric (2).

The working chamber is filled with fluid. In upward movements of the piston (6), the suction valve (4) is closed and the pressure valve (5) is opened. The fluid now flows to the system via the pressure port (P).

Type code

Design options with multi-circuit pumps The following can be seen from the following schematic representations: the number and position of the pressure ports which cylinders are combined. Points mark the cylinders which are directly located at the pressurized pressure port. Circles mark the cylinders which are not directly located at the pressurized pressure port. The dashed and/or dot and dash lines show which cylinders are in each case combined. The pressurized pressure ports are designated in clockwise direction. The pressure port that - in clockwise direction - is closest to the suction port is referred to as P1 .
Type code (Pos. 08)	Number of pressure ports	Combination of cylinders
		3 pistons	5 pistons	10 pistons
01	1
02	2
03	3
08	5
11	6
12	10

Technical data

Uniformity coefficient f relative to n = 1450 rpm

The values from "Flow/drive power" table relate to 1 cylinder each.

To determine the required drive power, multiply the specified value by the number of cylinders.

The uniformity coefficient f should be taken into account.

Radial piston pump (specifications apply for a frequency of 50 Hz)
3 cylinders		5 or 10 cylinders
Loaded cylinder	Factor f	Loaded cylinder	Factor f
1	3.13	1	3.13
		1+2	1.89
1+2	1.57	1+3	1.57
		1+2+3	1.60
		1+3+4	1.35
		1+2+3+4	1.30
1+2+3	1	1+2+3+4+5	1
At pumps with 10 cylinders, 2 cylinders each are switched at a pressure port.

▼ Example: Pump PR4–3X/1,60–700RA01M02

Port 1 and 2 are connected together and loaded with 450 bar, 3 is circulating at zero pressure.

PA = 2 × 0.605 kW = 1.21 kW

f = 1.57

Perf = 1.21 kW × 1.57 = 1.90 kW

Port 3 loaded with 300 bar, 1 and 2 run without pressure.

PA = 1 × 0.42 kW = 0.42 kW

f = 3.13

Perf = 0.42 kW × 3.13 = 1.31 kW

Port 1, 2 and 3, each loaded with 200 bar.

PA = 3 × 0.29 kW = 0.87 kW

f = 1

Perf = 0.87 kW × 1 = 0.87 kW

Diagrams/characteristic curves

Sound pressure level (average):

(measured at n = 1450 min-1, v = 41 mm2/s and ϑ = 50 °C in a sound measuring chamber according to DIN 45635, part 26, Distance microphone – pump = 1 m)

The characteristic curves do not apply for versions with multiple circuits.

3-piston pump

5-piston pump

10-piston pump

Characteristic curves – Flow:

(measured at n = 1450 min-1, v = 41 mm2/s and ϑ = 50 °C)

Characteristic curves – Drive power:

(measured at n = 1450 min-1, v = 41 mm2/s and ϑ = 50 °C)

Dimensions

Radial piston pump with 3 pistons

Dimensions in mm

Radial piston pump with 5 pistons

Dimensions in mm

• Cylindrical shaft end

• Shaft end with serration according to DIN 5481

Radial piston pump with 10 pistons

Characteristic 01, 02 and 08
Dimensions in mm

• Cylindrical shaft end

• Shaft end with serration according to DIN 5481

Radial piston pump with 10 pistons

Characteristic 11 and 12
Dimensions in mm

• Cylindrical shaft end

• Shaft end with serration according to DIN 5481

Pump combination P2R4...

Other dimension see Dimensional drawings of PR4

Pump combination P3R4...

Other dimension see Dimensional drawings of PR4

Project planning information

Installation instructions

Fluid tank

• Adjust useful volume of the tank to the operating conditions.

• The admissible fluid temperature must not be exceeded; use coolers, if necessary.

Lines and ports

• Remove protection plugs from the pump.

• We recommend the use of seamless precision steel pipes according to DIN EN 10305-1 and removable pipe connections.

• Select the clear width of pipes according to the ports (suction speed 1 to 1.5 m/s).

• Inlet pressure, see technical data.

• Thoroughly clean pipelines and fittings prior to installing.

Proposal for piping layout

• Under no circumstances may drain and returning fluid be drawn directly into the suction port again, i.e., select the largest possible distance between suction line and return line.

• The return drain must always be below the oil level.

• Ensure suction-tight installation of the pipes.

Filter

Use a return flow or pressure filter, if possible.

(Suction filters only in connection with underpressure switch/clogging indicator).

Hydraulic fluid

• Please observe our specifications according to data sheet 90220.

• We recommend brand name hydraulic fluids.

• Do not mix hydraulic fluids of different types since this can result in decomposition and deterioration of the lubricity.

• The hydraulic fluid must be replaced at regular intervals according to the operating conditions. When doing this, the hydraulic fluid reservoir must also be cleaned of residues.

Drive

Electric motor + pump carrier + coupling + pump

• No radial or axial forces permissible on the pump drive shaft!

• Motor and pump must be exactly aligned!

• Always use a coupling that is suitable for compensating for shaft offsets!

• When installing the coupling, avoid axial forces, i.e., when installing, do not hammer or press the coupling onto the shaft! Use the female thread on the drive shaft.

Installation positions

B3

B5

V1

Project planning information

When using radial piston pumps, we recommend particularly observing the information specified below. Project planning, assembly and commissioning of the radial piston pumps require the employment of trained experts.

Technical data

All specified characteristic depend on production tolerances and are valid at certain boundary conditions. Please note that consequently, certain scatter ranges are possible and that with changed boundary conditions (e.g. viscosity), the characteristics may also change.

Characteristic curves for flow and consumed power

When designing the drive motor, please observe the maximum application parameters possible.

Noise

The values for sound pressure level shown under Diagrams/characteristic curves have been measured according to DIN 45635 part 26. That means only the sound emission of the pump is shown. Environmental influences (such as place of installation, piping, etc.) have been eliminated. The values are in each case only valid for one pump. For circulation at zero pressure, the pressure line must be preloaded by means of a check valve (cracking pressure p = 5 bar) due to noise development.

Notice

Due to the power unit construction and the influence at the final place of installation of the pump, the sound pressure level will usually be 5 to 10 dB(A) higher than the value of the pump itself.

Project planning information for multiple pumps

Single pump	Example: Pump combinationP3R4-3X/3.15-700...+AZPFF8-4 Tab2 = 45 Nm T3 = 3.8 Nm ≤ Tab2 max Tab1 = 45 Nm T1,2 = T2 + T3 T1,2 = 18.8 Nm ≤ Tab1 max Tmax = 160 Nm T = T1 + T2 + T3 T = 63 Nm ≤ Tmax
Combination pump
Calculation example: V = displacement in cm3 ηhydr.-mech. = hydraulic-mechanical efficiency T = torque in Nm Δp = pressure in bar	The pump combination can be operated with the calculated key data.

Commissioning

Commissioning instructions

Air bleeding

• All PR4 radial piston pumps are self-priming.

• Fill the housing with filtered oil via port S.

• During initial commissioning, set the pump to pressureless circulation. To do so, release the pressure hose and direct it into the reservoir.

• Before initial commissioning, the pump must be air-bled to protect it against damage.

• Switch to pressureless circulation, or direct the pressure line or pressure hose back into the reservoir.

• Briefly switch the pump on (inching mode).

• Should the pump not displace bubble-free oil after approx. 20 seconds, re-check the system. After the operating values have been reached, check the pipe connections for leakage. Check the operating temperature.

• Be aware of noise generation.

Commissioning

• Check whether the system is thoroughly and properly installed.

• Start the pump without load and let it displace fluid without pressure for a few seconds in order to ensure sufficient lubrication.

• In no case may the pump be operated without hydraulic fluid!

Note

• Adjustment, maintenance and repair of the pump may only be carried out by authorized, trained and instructed personnel!

• Use only original Rexroth spare parts!

• The pump may only be operated within the permissible data.

• The pump may only be operated when in perfect condition!

• When carrying out any work on the pump (e.g. installation and removal) the system must be switched off and depressurized!

• Unauthorized conversions and changes, affecting the safety and function are not permissible!

• Mount protective devices (e.g., coupling protection)!

• Do not remove any existing protective devices!

• The generally valid safety and accident prevention regulations must be strictly observed!

Downloads

Fixed displacement radial piston pump Data Sheet | RE11263 | 2013-05-01 | English | PDF | 504k Product Groups: Radial piston pumps Type PR4