Investigation of the Churning Loss Reduction in 2D Motion-Converting Mechanisms

Abstract

In recent years, two dimensional (2D) hydraulic components have significantly flourished. After a brief development introduction of the 2D pump and 2D flowmeter, it could be concluded that the churning loss, which is caused by the rotational motion of 2D motion-converting mechanisms, has an increasing effect on reducing energy losses. This paper first presents a new 2D motion-converting mechanism and introduces its structure and working principles. To compare it with the former 2D motion-converting mechanism, the same working conditions were applied when designing the new one. Afterward, the generated churning loss by the active parts of the mechanism, such as the new rotor, was well studied by establishing a simplified CFD simulation model and was also verified to have a smaller churning loss than that of the former mechanism. As another key simulation result, the influence of the axial motion of the new rotor was found to be negligible for the churning loss even when the rotational speed was high enough. A test rig was subsequently built up to prove the simulation by monitoring the torque at various rotational speeds. As a result, the churning losses that took place in the new 2D motion-converting mechanism were certainly reduced, and the potential reasons for that were analyzed, as shown in the conclusion section.

Study on mechanical efficiency in a 2D piston pump with rail rotation based on Hertz contact theory

“…In addition, the churning loss of the guiding rail rotating is less than that of the roller rotating, which is conducive to an increase in mechanical efficiency at high rotational speeds. 21–23…”

“…In addition, the churning loss of the guiding rail rotating is less than that of the roller rotating, which is conducive to an increase in mechanical efficiency at high rotational speeds. [21][22][23] In Figure 3(a), the left working chamber is at the maximum volume, and the right working chamber is at the minimum volume. Then, the left working chamber starts to discharge oil and the right working chamber starts to suction oil.…”

“…The rotation of the motion set is influenced by the churning losses torque under high speeds. The churning losses torque of the 2D piston pump with rail rotation is lower than that of the suspension rotation and can be described by equation ( 7) 22 T c = 5:44…”

Design and research of 2D piston pumps with a stacked cone roller set

“…One is the oil churning losses torque T c caused by the rotation of the guiding rail in the enclosed chamber, as reported by Huang and Ding. 20,22 Equation (40) is fitted through simulation and experimental data to obtain the churning torque T c . The other is the oil shearing torque T s caused by the oil flow in the gap between the distribution cylinder and the cylinder block and is expressed by equation (41):…”

“…When the distribution cylinder rotates 18 degrees, the contact length L r is 0, and the distribution groove of the distribution cylinder does not communicate with the suction and discharge ports of the cylinder block. The circumferential leakage flow q Li2 can be expressed by equation (22):…”