Optimization Design Of One Tooth Difference Cycloidal Gear Pump

With the popularization of cars, more and more families have their own private cars.In the meantime, however, the extensive use of cars has brought increasingly severe energyand to environmental pollution problems. For the automotive industry, the requirementsover environmental protection are higher and higher, and energy conservation andemission reduction have become a trend in the automotive development. In the automatictransmission, the oil pump loss is equivalent to about10%of the entire transmission loss,so the reduction of oil pump loss can achieve energy conservation and emission reduction.The most commonly used automatic transmission includes oil pump, vane pumps andelectric pumps. Although many domestic and foreign finished automobile and transmissionmanufacturers are developing vane pumps and electric pumps, researches on vane pumpsand electric pumps are still in their infancy stage among the automatic transmission inChina. Most manufacturers still use the gear pumps. Among this, due to compact structure,small volume, stable operation, low noise, no cavitation, good high-speed performance andother advantages, one-tooth difference cycloid gear pump is widely used.Based on the gear pump principle as well as cycloid and rotor tooth generationprinciple, this paper analyzes the transmission characteristics of the cycloid rotor andmechanical characteristics, and proposed three optimization directions for one-toothdifference cycloid gear pump: optimization of cycloid rotor profile curve, optimization ofcycloid rotor clearance and optimization of gear pumps oil grooves matching. This paperuses the new rotor profile curve to reduce the rotor volume and the pressure angle ofmeshing region, in order to improve the mechanical efficiency of oil pump under thecondition of unchanged basic performance of oul pump. Based on analysis of the cycloidrotor transmission characteristics, this paper studies the tooth shape modification methodsfor cycloid rotor, bases on the traditional isometric, shifting and rotated angle modificationmethods, and proposes a new tooth modification method, in order to reduce themanufacturing accuracy requirements of rotor, meet the design of small clearance rotor,and increase the volume efficiency of the oil pump. Furthermore, this paper optimizes anddesigns the oil passages, achieves the reasonable feeding delay and dischargingpre-compression, adopts the method of test after simulation, verifies the reasonableness offeeding and discharging oil passage design, further bases on the actual design experience, and improve the volumetric efficiency of the oil pump by increasing the balance tank andhigh-pressure sealed tank.In order to verify the reasonableness and effectiveness of the above optimal design,this paper conducts an optimal design for a certain existing product, and carries outexperiment to verify based on ATA oil pump performance test bench. The test resultsshowed that after the optimal design, the pump efficiency and noise are obviouslyimproved without changing the oil pump appearance, and thus realizes the purpose ofoptimal design.