Abstract:In order to solve the problem of volume efficiency reduction caused by axial leakage in external gear pumps,an new structure scheme of external gear pump without axial leakage was proposed,in which a new structure of synchronous disc shaftfloating side plate bearing with diameter between the root circle and the pitch circle was used to replace the structure of sliding bearing of ordinary pump with diameter less than the root circle,and two pairs of synchronous disk shaft was respectively fixed on frontend and backend of driving gear and driven gear.The calculation formula of compression force and compression force coefficient and the axial leakage were derived.an example of calculation and analysis was given.The results show that the compaction force coefficient of the new structure of gear pump without axial leakage is 118,which meets the requirement of less than 12.The axial leakage rate of the new structure is only 7% of that of the original structure,which can be really regarded as no axial leakage.The eccentricity is reduced by 11%,and the minimum oil film thickness is increased by 4%,which is helpful for lubricating performance improvement.The bearing width is reduced from 15 mm to 10 mm,which is helpful for reducing axial size and lightweight design of gear pumps.