Variable Displacement Catalog 9129 8222-02 February 1999, GB
Content Page General information 3 Design 3 Specifications 4 Ordering information 4 VP1 cross section 4 Installation dimensions 5 Line dimensioning 5 BPV-VP1 bypass valve 6 FDV-VP1 unloading valve 6 VP1 fitting kits 6 VP1 in load sensing systems 7 The VP1-LS load sensing control 8 Tandem coupling 9 Installation and start-up 10 Conversion factors 1 kg 2.20 lb 1 N 0.225 lbf 1 Nm 0.738 lbf ft 1 bar 14.5 psi 1 l 0.264 US gallon 1 cm 3 0.061 cu in 1 mm 0.039 in 9/ 5 C + 32 1 F Parker Hannifin reserves the right to modify products without prior notice. Even though the brochure is revised and updated continuously, there is always a possibility of errors. For more detailed information about the products, please contact Parker Hannifin (VOAC Hydraulics Div.) 2
The VP1 is the world's first variable displacement pump for truck applications. It can be closecoupled to a power on the gearbox take-off or on a coupling independent PTO (e. i. an engine PTO) which meets ISO standard 7653-1985. An application that makes full use of all the features of the VP1 is truck cranes with a loadsensing system. The complex systems of refuse collection vehicles and sewage trucks as well as various combinations of tipper, crane, snow ploughs, and salt/sand spreader can also be greatly simplified and optimized with the VP1 pump. The VP1 pump provides the hydraulic system with the correct amount of fluid at precisely the right moment, effectively reducing energy consumption and heat generation. This means a smoother and quieter running system with lower energi consumption. The VP1 is highly efficient, has a small installation envelop and is extremely lightweight. It is reliable, economical and easy to install. The two frame sizes, VP1-45 and -75, have the same, small installation dimensions. Shaft and mounting flange follow the European ISO standard 7653-1985. The VP1 is suitable for all load-sensing systems, regardless of make. Advantages Variable displacement Low noise level High power-to-weight ratio Compact and lightweight Highly efficient Sturdy design Withstands low temperatures High reliability and serviceability Can be close coupled and tandem mounted Design Large angle - compact design The pump design permits a large angle, 20, between piston and slipper shoe/swashplate, providing compactness and small outer dimensions. Tandem coupling The through shaft permits tandem coupling of an additional pump, such as a series F1 fixed displacement pump. Accepts external shaft loads Heavy duty roller bearings allow radial loads to the VP1 shaft end which makes it possible to install a gear directly on the shaft without additional bearings. High overall efficiency Uniquely designed parts like the piston/slipper shoe and 'floating' valve plate minimize mechanical losses. The valve plate floats on five pistons, resulting in a quieter operating pump with low internal leakage and high volumetric efficiency. Retainer plate The retainer plate (refer to the cut-away illustration on page 4) is of a heavy duty design which makes the pump withstand high shaft speeds and fast speed changes. Long life The VP1 is designed for trucks with hydraulic load sensing systems. It is sturdy, yet simple, with few moving parts. The result is a reliable pump with long service life. 3
Specifications Frame size VP1 45 VP1 75 Max displacement [cm 3 /rev] 45 75 Max pressure [bar] peak 350 continuous 1) 300 * Refer to page 8, 'LS control'. Response time [ms] max-to-min 20-30 20-40 min-to-max 90-120 100-140 Selfpriming speed 2) [rpm] 2" suction line, max 2200 1700 2 1 / 2 " suction line, max 2400 2100 Control type LS Splined shaft end DIN 5462 Mounting flange ISO 7653-1985 Weight (with control) [kg] 27 2) At an inlet pressure of 1.0 bar (absolut) with mineral oil, viscosity 30 mm 2 /s (cst). Ordering information Example: VP1-045 - L Frame size 45 or 75 Direction of rotation L Left hand R Right hand NOTE: The VP1 is uni-directional; the desired direction of rotation must be stated when ordering. Standard model numbers VP1-045-R 378 0334 VP1-045-L 378 0335 VP1-075-R 378 0336 VP1-075-L 378 0337 VP1 cross section 1. Inlet port 2. 'Top' purge plug 3. Return spring 4. Control 5. Setting piston (one of two) 6. Swash plate 7. Bearing shell 8. End cover 9. Spline (auxiliary pump mounting) 10. Bearing sleeve 11. Hold-down plunger 12. Bi-metal valve plate 13. Cylinder barrel 14. Barrel housing 15. 'Bottom' purge plug 16. Piston with piston shoe 17. Retainer plate 18. Bearing housing 19. Roller bearing 20. Shaft seals with carrier 21. Input shaft 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Installation dimensions (VP1-45 and -75) 73 max 73 max (R.H rotation) (L.H rotation) 107 max 46 min 'Top' purge plug IMPORTANT The control is not drained through the pump case. An external line must be installed between the control drain port 'T' and the reservoir. 73 min 56 11.8 27.8 1.85 115 ø34.9 +0/-0.1 71 max ø80 f7 (ISO 7653-1985) ø33 80 ø 13 (x4) 'Bottom' purge plug 15 8.5 B8x32x36 120 max 20 max 256.5 55 (DIN 5462) 132 max 'Top' gauge port; BSP 1/ 4 " Outlet (pressure) port; BSP 1" (L.H. rotation) Control drain port T (BSP 1 / 4 ") Outlet gauge port; BSP 1/ 4 " (L.H. rot'n) Inlet (suction) port; BSP 11/ 4 " 43 LS T M12 thread (24 deep) Outlet gauge port; BSP 1/ 4 " (R.H. rot'n) 43 37 ø 8.1 +0.1/-0 29 34 Outlet (pressure) port; BSP 1" (R.H. rotation) Load sensing port LS (BSP 1/ 4 ") Line dimensioning To ensure a minimum of heat losses and low noise level in the hydraulic system, don't exceed the max recommended inlet and outlet line flow limits, shown to the right. From the table below, select the inlet (suction) and outlet (pressure) line sizes that will provide flow velocities below these limits. Note that larger line dimensions may be required for unfavourable inlet conditions caused by sharp bends and/or long lines. Flow Line type Flow velocity [m/s] Inlet (suction) max 0.8 Outlet (pressure) max 5.0 Flow velocity [m/s] at selected line sizes [mm/inches] [l/min] 19 / 3 / 4 " 25 / 1" 32 / 1 1 / 4 " 38 / 1 1 / 2 " 51 / 2" 64 / 2 1 / 2 " 25 1.5 0.8 0.5 0.4 0.2 0.1 50 2.9 1.7 1.0 0.7 0.4 0.3 75 4.4 2.5 1.6 1.1 0.6 0.4 Inlet (suction) line 100 (5.9) 3.4 2.1 1.5 0.8 0.5 150 (8.8) (5.1) 3.1 2.2 1.3 (0.8) Outlet (pressure) line 5
Accessories BPV-VP1 bypass valve* The BPV-VP1 bypass valve is utilized in hydraulic systems where the pump is engaged constantly. The valve, which requires no additional control valve, allows the pump to operate on- or off-load up to its max selfpriming speed. The valve protects the pump from overheating in the off-load mode by allowing a small flow to circulate through the pump (refer to the schematic to the right). When a load sensing valve function is engaged, the bypass flow is cut off (as port 'X' is being pressurized). VP1 pump Bypass valve (5 bar) P S T X Load sensing valve Valve Ordering Rated flow Max press. type number [l/min] [bar] BPV-VP1 379 8799 20 350 Nozzle Load sensing (LS) signal FDV-VP1 short-circuiting valve* The FDV-VP1 short-circuiting valve is used in hydraulic systems where two directional control valves are utilized: 1. An open center valve for e.g. tipper and/or support legs that don't benefit from a load sensing function. 2. A load sensing valve for the remaining work functions. When a section of the open center control valve is engaged and the FDV solenoid is energized, the VP1 pump load sensing line is short-circuited to the pump outlet. The pump then goes to max displacement and operates as a fixed displacement pump. Valve Ordering Rated flow Max press. type number [l/min] [bar] FDV-VP1 379 8937 153 350 VP1 pump Unloading valve '1' '2' '3' Open center control valve Solenoid (24 VDC/19 W) Load sensing (LS) signal Load sensing control valve VP1 fitting kits* Fitting kits with straight, 45 or 90 inlet (suction) fitting are available; refer to the illustration to the right. C 1 60 A fitting kit contains a pressure fitting, an inlet fitting and corresponding seal washers. Fitting kit with straight inlet fitting C 2 Ordering no. Kit C1 C2 370 4936 Straight BSP 3 / 4 " 2" 370 7220 " BSP 1" 2" 379 9563 45 BSP 3 / 4 " 2" 379 9562 " BSP 1" 2 1 / 2 " 379 9917 90 BSP 1" 2" * Additional information is provided in our 'Truck Accessories' bulletin (catalog no. 9129 8242-02; page 15, 16 and 3 respectively). Fitting kit with 45 adjustable inlet fitting C 1 60 C 2 C 2 C 1 60 Fitting kit with 90 adjustable inlet fitting 6
VP1 in load sensing systems When installed in a load sensing system, the VP1 supplies the correct amount of flow required by the various work functions currently engaged. This means that energy consumption and heat generation are minimized and much reduced in comparison with a fixed displacement pump used in the same system. Diagram 1 shows the required power (flow times pressure) in a constant flow system with a fixed displacement pump. Pressure Corner power Diagram 2 shows the sharply reduced power requirement in a load sensing system with a variable displacement pump such as the VP1. In both cases the pump pressure is slightly higher than what is required by the heaviest load ('Load 2'), but the VP1, because of the much smaller flow being delivered, needs only the power indicated by the shaded area 'Load power'. In a constant flow system, on the other hand, excess fluid is shunted to tank and the corresponding power, 'Wasted power', is a heat loss. Pressure Corner power p Max p Max p Load Load 1 Load 2 Load power Load 3 Wasted power p Load Load 1 Load 2 Load power Load 3 Q Load 1-3 Flow Q max (pump) Q Load 1-3 Flow Q max (pump) Diagram 1. Constant flow system with fixed displacement pump. Diagram 2. Load sensing system with variable displacement pump (VP1). Systems comparison System Constant flow Load-sensing Pump Fixed displ. VP1 variable displ. Pump adjustments Pressure only Pressure and flow Load* Some No influence influence Energy consumption High Low Heat generation High Low * Simultaneous operation of loads with different flows and pressures; refer to the above diagrams. 7
The VP1-LS load-sensing control The VP1 pump with LS control can be used with any load-sensing directional valve on the market. The control governs the pump flow to the main hydraulic system as determined by the pressure differential, p, between the pump pressure and the LS load signal pressure. At a certain 'opening' of the directional valve, the pump flow is kept constant (up to max specified rpm and pressure limits of the pump) even if the pump pressure changes due to increasing or decreasing work load. The LS control (fig. 2) consists of a valve body, which installes on the main pump housing, with a built-in, spool-type load-sensing control, and a pressure relief valve limiting the LS signal pressure. Both are adjustable. The two-position, three-way spool valve is connected to system pressure, the LS load signal, and the two setting pistons (fig. 1). In the no-flow mode, the pump maintains a standby pressure as determined by the setting of the valve spring (there is no pressure in the LS signal line from the directional valve). The pressure limiter consists of a cartridge valve (fig. 2); the setting limits the LS signal pressure. LS load sensing control function Refer to the hydraulic schematic (fig. 1). A selected 'opening' of the directional control valve spool corresponds to a certain flow to the work function. This flow, in turn, creates a pressure differential over the spool and, consequently, also a p between the pump outlet and the LS port. When the differential pressure decreases (e.g. the directional valve is 'opened' further) the p also decreases, and the LS valve spool moves to the left; the pressure to the setting pistons decreases and the pump displacement increases. The increase in pump displacement stops when the set p finally is reached and the forces acting on the valve spool are equal. If there is no LS signal pressure (e.g. when the directional valve is in the neutral, no-flow position) the pump only delivers sufficient flow to maintain the standby pressure as determined by the setting of the LS valve spring. 5 6 Directional, load-sensing control valve T To work function A B T P LS Min 1 2 3 4 LS control adjustments LS signal pressure limiter The cartridge is factory set at 275 bar but is adjustable to 350 bar. Standby pressure The p is factory set at 25 bar but is adjustable between 20 and 35 bar. Factory settings and the orifices that the control is supplied with is the reason why the VP1 can be used in connection with most load sensing valves on the market. For additional information, contact Parker Hannifin (VOAC Hydraulics Division). Setting pist.1 Setting pist. 2 Fig. 1. Hydraulic schematic. Max Legend 1. Load signal orifice 4. Differential pressure (1.0 mm; fixed) adjustment 2. Signal pressure 5. System pressure limiter adjustment damping nozzle (2.0 mm) 3. Return line nozzle 6. Bleed-off nozzle (1.0 mm) (1.0 mm) 8
Load sensing port (BSP 1 / 4 ") Control drain port (BSP 1/ 4 ") A Signal pressure limiter adjustment O-ring (x6) 1 LS T 2 4 5 Damping nozzle (L.H. rotating pump) (To setting piston 1) (To setting piston 2) Differential pressure ( p) adjustment 5 Damping nozzle (R.H. rotating pump) A Top view Pressure limiting cartridge Bottom view 6 3 Setting spring Valve spool Cross section Fig. 2. LS valve block. Section A A Through-shaft coupling The VP1 pump has a through-shaft which means that an auxiliary pump, such as a fixed displacement F1, can be installed in tandem with the VP1 by means of an adaptor kit (fig. 3). NOTE: The bending moment caused by the weight of a tandem assembly normally exceeds what is allowed on the PTO. To prevent damage, the auxiliary pump should be supported by a bracket attached to the gearbox; it must not be fastened to the truck chassis. Likewise, when the tandem assembly is installed on a separate bracket and driven by a cardan shaft, the auxiliary pump should have a support attached to the pump bracket. VP1 pump Add-on pump Fig. 3. Tandem coupling adaptor kit (P/N 379 7795). IMPORTANT Contact Parker Hannifin (VOAC Hydraulics Div.) for additional information when considering tandem mounting of a second VP1 pump. 9
Installation and start-up Direction of rotation The basic VP1 pump is uni-directional; there is a left hand and a right hand version (indicated by the arrow on the side of the VP1 pump (fig. 4 and 5). The required direction of rotation must be stated when ordering the pump. Installation The VP1 can be installed (close-coupled) directly on a PTO which is manufactured according to ISO DIN 5462. Before start-up, the pump must be purged; utilize the uppermost purge plug (refer to the installation drawing on page 5). Figure 6 shows three ways of installing a gear on the VP1 shaft. On a PTO with support bearings, the pump shaft is usually installed directly in the internally splined PTO output shaft. IMPORTANT Force must never be used when installing a coupling, sleeve or gear on the VP1 pump shaft. The tool shown in fig. 7 (ordering no. 370 6851) facilitates the installation. Fig. 4. Left hand rotating pump. Fig. 5. Right hand rotating pump. Hydraulic fluids The VP1 data shown in the specifications on page 4 are valid when operating on a high quality, mineral based fluid. Hydraulic fluids type HLP (DIN 51524), ATF (automatic transmission fluids), and API type CD engine oils are suitable. Fluid temperature Main circuit: Max 75 C. Viscosity Recommended viscosity: 20 to 30 mm 2 /s (cst). Operating viscosity limits: Min. 10, max 400 mm 2 /s. At start-up: Max 1000 mm 2 /s. Filtration To obtain long VP1 life, we recommend a filtration level of: 25 µm (absolute) in clean environment or at low pressures. 10 µm (absolute) in contaminated environment or at high pressures. Filtration should meet ISO standard 4406, code 18/13. Fig. 6. VP1-to-PTO installation. Fig. 7 Installation tool (P/N 370 6851). 10
Drain line The LS control valve requires a separate drain line; it should be routed directly to the reservoir (refer to fig. 8). Before start-up, open the uppermost plug, purge the pump, and tighten the plug. Start-up Make sure the entire hydraulic system is clean before filling it with a recommended fluid. In addition, the VP1 pump must be purged to remove any entrapped air in the pump housing; utilize the uppermost purge port (fig. 8). IMPORTANT As shown in fig. 8, the pump inlet must always be below the lowest oil level in the reservoir. Fig. 8. VP1 should be installed below the reservoir fluid level. 11
Please contact our sales representative: Parker Hannifin AB VOAC Hydraulics Division SE-461 82 Trollhättan Sweden Tel +46 520 986 00 Fax +46 520 371 05 www.parker.com Catalog 9129 8222-02 Ed. 1664-9907 GB