高压子母叶片泵流量均匀性

FLUCTUATION OF FLOW IN HIGH PRESSURE VANE WITHIN VANE TYPE PUMP

针对液压用油的可压缩性,研究高压子母叶片泵流量均匀性及其改善的办法。对液压传动领域中传统的忽略油液可压缩性的理论瞬时流量公式进行修正,建立考虑油液可压缩性时的理论瞬时流量数学模型,绘出理论瞬时流量波形图,计算出流量不均匀系数。通过研究泵的工况参数变化与流量不均匀系数的关系,确定影响高压子母叶片泵流量均匀性的主要因素是油液的体积弹性模量、泵的工作压力、转速和阻尼的结构型式及参数,而不是排油腔几何容积变化率的不均匀性。研究结果表明,选择合适的阻尼结构型式及参数,使工作腔在预升压过程中,由机械闭死压缩、阻尼倒灌及吸油区叶片伸出耗油而产生的瞬时损失流量在时域上叠加,并将叠加后的幅值近似为常值,可有效地改善泵的瞬时流量均匀性。

Aiming at the compressibility of fluid, the flow ripple and method to improve it are studied. The conventional discharge flow formula of a high-pressure vane within vane type pump in fluid drive field power transmission is corrected, which is calculated when the fluid is considered to be incompressible. In order to simulate the actual discharge flow and calculate the uneven coefficient of flow ripple, a mathematic model of theoretical flow is built when the fluid compressibility is considered. Through the study of relationship between working condition parameter and flow ripple of pump, it reveals that the fluid bulk modulus, discharge pressure, rotate speed and the structure of relief grooves are the main influential factors of flow-tipple. The results show that choosing appropriate structure and parameters of relief grooves to make the overall losing flow almost constant can reduce the flow ripple of pump effectively. The overall losing flow is generated by compressed flow, backfilling flow and negative flow due to the thickness of vane.