2016 Volume 10 Issue 9 Pages JAMDSM0107
The vibration acceleration and temperature changes of the sliding parts of a vane-type hydraulic pump were measured simultaneously, including under the operating condition in which vane tips became detached. The test pump was a compact vane pump with 12 vanes having a theoretical displacement of 9.4 ml/rev, a maximum discharge pressure of 21 MPa, and a maximum rotational speed of 30 s-1. The vanes were inserted front to back into the slots of the pump rotor in order to allow ease of detachment. An acceleration pickup was affixed to the cam ring. In addition, four thermocouples were embedded in the cam ring, and four thermocouples were embedded in the side-plate. A hydraulic oil with ISO VG32 was used as the test fluid, and the inlet oil temperature was set to 40-60°C. The rotational speed was set as high as 15 s-1. The discharge pressure was increased in 1 MPa increments up to 10 MPa, and the oil temperature and rotational speed were held constant until detachment occurred. The experimental results revealed that detachment of the vane tip from the cam ring was easy to occur at lower discharge pressure under the conditions of high oil temperature and low rotational speed. When the vanes began to repeatedly and violently detach and reattach, the cam ring temperature instantly decreased and subsequently increased markedly, while the vibration acceleration increased greatly.
