Parker Hannifin Introduces Compact Gear Pumps for Mobile Equipment Applications
December 4, 2006•
Enlarge Image
Parker Hannifin's 600 Series compact gear pumps feature an interlocking flange and compact two-piece construction.
The initial 600 Series product offering includes three different models: the 610 with displacements from 0.37 to 2.14 cir (6 to 35 cc/rev); the 620 with displacements from 0.98 to 3.17 cir (16 to 52 cc/rev); and, the 640 with displacements from 1.83 to 4.88 cir (30 to 80 cc/rev). All are rated for continuous pressures of 4,500 psi (310 bar) at operating speeds up to 3,500 rpm and offer 99% volumetric efficiency.
These models are available in pump or motor configurations and can be supplied with rear ports where required. The 600 Series features multiple sections and cross frames with a common inlet and a choice of rear- or side-mounted priority valves. Options include load-sensing priority valves; relief valves and unloaders for pumps; and relief valves, anti-cavitation valves, and proportional relief valves for motors.
The 620 is available with a specially-engineered “stealth” gear set, in which the teeth are phased by half a tooth pitch. This significantly reduces both flow and pressure ripple while eliminating the first and third harmonic at the tooth frequency.
According to Parker GPD General Manager Brian Nadel, the 600 Series is a response to emerging customer requirements for quieter, more-efficient pumps that can operate in the higher temperature environment created by Tier 3 and upcoming Tier 4 diesel emission regulations.
“Tomorrow's cleaner diesels will generate significantly more heat than their predecessors, and that trend will accelerate,” Nadel said. “As it does, the total heat load from engine oil, air conditioning refrigerant, transmission, drive train, hydraulic fluids, combustion charge air pre-conditioning, and even control of ambient temperature inside the engine compartment will also grow.”
He added that hydraulic cooling is taking over an increasing share of the diesel cooling market, and the 600 Series is aimed at that type of application. The 600 Series uses a cast iron housing rather than aluminum because its greater strength and better thermal stability permits high continuous pressures and higher shaft speeds when compared to aluminum units of similar capacity.
While gear pumps and motors have periodically been identified as a technology nearing obsolescence, continuing design improvements, supported by sophisticated design and manufacturing technologies, have kept them in the forefront of mobile hydraulic applications. Parker reports that gear-type pumps and motors are rapidly becoming the technology of choice, not only for traditional mobile applications, but also for emerging uses such as hydraulic cooling.
“Advanced CAD technology has had a profound impact on gear pump design,” Nadel says. “They're smaller, more efficient, more reliable, and quieter, as a result of sophisticated features like dual flank and split gear designs. Not to mention the advances in heat treatment and surface finishing we have today, or the sealing technologies, or the improved bearings, and the CNC machining centers to generate the computer-optimized housing contours and profiles, and advanced hobbing machines to produce the gears.”
He added that this is why today's gear pumps can compete favorably with other technologies, and why the 600 Series design team was able to produce pumps and motors with high volumetric efficiencies, low noise levels, extended service lives, and compact envelopes, which makes the series better suited for mobile equipment applications.
