Comparison of temperature measurements and thermal characteristics of hydraulic piston, vane, and gear pumps

Abstract

Hydraulic pumps are positive displacement machines and the primary components of fluid power systems that transform energy from mechanical sources to pressurized oils. The reliability and efficiency of pump components are highly dependent on the tribological characteristics of the sliding parts, which perform bearing and sealing functions. Higher pressurization and increased compactness result in higher contact pressure and oil temperature, which can cause catastrophic damage to the components and severe deterioration of the oils. Three representative hydraulic pumps-including a swash plate axial piston pump, a pressure-balance vane pump, and an external gear pump-were tested under real operating conditions to determine their thermal effects. Discharge pressures up to 21 MPa and rotational speeds up to 50 s 1 were tested. Hydraulic oils with viscosity grades of 22, 32, and 46 were used at 30C50C. The thermocouples were embedded in the cylinder block, swash plate, and valve plate of the piston pump, cam ring and side plate of the vane pump, and the side plate of the gear pump. Platinum resistance thermometers were placed in the conduits close to the suction and discharge ports of the pumps. The temperatures of the sliding parts and working oils were measured simultaneously. Results indicated that for all pump tests, temperatures increased almost monotonically as the discharge pressure increased. The temperatures of the sliding parts were always higher than those of the discharge oils. With the piston pump, the temperatures at the locations corresponding to the discharge port of the swash plate and valve plate were higher. In contrast, with the vane pump, the temperature at the location on the cam ring closest to the suction port was highest.

Vibration and temperature variation of the cam ring of a hydraulic vane pump associated with vane tip detachment

“…In response to p d , the temperature differences of the cam ring, t C , and the side-plate, t S , from the inlet oil temperature, t in , increased. The changes in temperatures t C and t S are indicated by t C and t S , respectively, where t is defined by t = t -t in , because t is more clear and precise to evaluate the temperature changes (Kazama, 2013(Kazama, , 2015.…”

“…Furthermore, the relationship between the vane detachment and the temperature change is discussed and the possibility of a detection in a method other than measurement of noise , monitoring of flow rate (JHPS, 1989), and visualization of the vanes (Nishiumi and Maeda, 1993) is explored. Figure 1 shows the hydraulic circuit of the tester (Kazama and Narita, 2011;Kazama, 2013Kazama, , 2015. The test vane pump was mounted on the test bench, which consisted primarily of the hydraulic circuit, including valves, filters, an oil-cooler, and a reservoir.…”

Action mechanism of the overturning retainer and the slipper of axial piston machines

“…The swashplate type axial piston pump/motor is an energy conversion element with high power density and compact structure. 1,2 The suction movement of the piston-slipper assembly is facilitated by the retainer, which plays a crucial role in the functioning of the piston pump. 3 However, in certain faulty piston pumps, the friction at the fit clearance between the piston-cylinder bloc assembly is increased, resulting in severe wear between the slipper and the retainer, which eventually evolves into a fracture of the retainer.…”