Vol.29 SuppL 2 李威等：外啮合非对称齿轮泵优势分析 155。 1.16 0.021 ◆=13 1.12 0.019 ·2=14 p215 1.08 尊 0.017 1.04 0.015 1.00 0.013 0.965 20 25 30 35 /) 0.01634 0.38 0.420.46 0.50 0.54 压力角rad 图5△g.随工作侧压力角变化规律 图7脉动系数与压力角变化曲线 R T E 考虑到流量脉动系数= R二R和排量g= 目的. 2xBR品-R2-K.貿 5结论 由基本参数可以最后表达为2=fa),q=g(a, (1)非对称齿轮泵能够利用工作侧压力角的提 用MATLAB软件绘图得出图6和图7. 高或齿数的增加来增大泵的流量同时也能减小泵的 3.13 脉动系数，使其运行更加稳定 ◆2之=13 (2)齿轮做为齿轮泵的核心元件，主要失效形式 3.11 2=14 B2=15 为磨损，在不改变其他参数的情况下，可以通过改变 3.09 工作侧压力角，提高润滑性能从而达到减少磨损， 增加寿命的目的. 3.07 参考文献 3.0834038 【刂Kapelevich A.Geometry and design of inolute spur gears wit讪 0.380.420.46 0.500.54 asymmetric teeth.Mech Mach Theory,2000,35:117 压力角rad [2 Deng G.Nakanishi T.Bending load capacity enhancement using an asymmetric tooth profile.JSME Int J.2003.46(3):1171 图6流量与压力角关系变化曲线 [3习Kapelevich A.Geometry and止sign of spur gears wit讪 由上图可知，当压力角由20°提高到30°时（或 asym2metric teeth.Mech Mach Theory,2000.35:117 齿数增加时)，在流量获得了提高的同时脉动系数得 [4 Litvin F L.Lian Q.Asymmetric modified gear drives:redue2tion of noise,localization of contact,simultion of meshing andstress 到明显的减小，从而能够达到减小整个系统振动的 analysis.Comput Methods Appl Mech Eng.2000.188:363 The analysis of teeth wear and flux for gear pump with external meshing and un- symmetric teeth LI Wei,WANG Chengbing,WANG Xiaogun Mechanical Engincerin School University of Science and Technology Beijing.Beijing 100083.China ABSTRACT A new ty pe unsymmetric gear pump w ith double pressure angles was studied.New fommulas for the instantaneous flow and flow pulsation were put out.Compared with symmetric gear pump,the fomulas showed that the unsy mmetric gear pump could efficiently improve flow pulsation with the rise of instantaneous flow.It is concluded that the sliding coefficient of unsymmetric gear pump was smaller than that of symmetric gear pump.The increase of pressure angle of work side would cause an evident increase in the minimum oil-film thickness and in the specific ratio of oil-film thicknes,which is helpful to improve the lubricant characterist ics of gear teeth surface.The practical significance of the present gear is demonstrated by the computer simulation with M ATLAB software,such predictions can provides the firm basis for the further engineering application of this new-type gear pump with unsymmetric teeth and double pressure angles. KEY WORDS unsymmetric gear pump;work principle;flow pulsation;lubricant characteristics图 5 Δg e 随工作侧压力角变化规律 考虑到流量脉动系数 δQ = R 2 b πε z 2 R 2 a1 -R 2 和排量q = 2πB R 2 a1 -R 2 -K e π 2 R 2 j 3z 2 由基本参数可以最后表达为 δQ =f ( a ), q =g ( a ), 用 MATLAB 软件绘图得出图 6 和图 7 . 图 6 流量与压力角关系变化曲线 由上图可知, 当压力角由 20°提高到 30°时( 或 齿数增加时), 在流量获得了提高的同时脉动系数得 到明显的减小, 从而能够达到减小整个系统振动的 图7 脉动系数与压力角变化曲线 目的. 5 结论 ( 1) 非对称齿轮泵能够利用工作侧压力角的提 高或齿数的增加来增大泵的流量同时也能减小泵的 脉动系数, 使其运行更加稳定. ( 2)齿轮做为齿轮泵的核心元件, 主要失效形式 为磨损, 在不改变其他参数的情况下, 可以通过改变 工作侧压力角, 提高润滑性能, 从而达到减少磨损, 增加寿命的目的. 参 考 文 献 [ 1] Kapelevich A .Geometry and design of involute spur gears w ith asymmetric teeth.Mech Mach Theory, 2000, 35:117 [ 2] Deng G, Nakanishi T .Bending load capacity enhancemen t using an asymmetri c tooth profile .JSME Int J, 2003, 46( 3) :1171 [ 3] Kapelevich A .Geometry and design of spur gears w ith asym2metric teeth.Mech Mach Theory, 2000, 35:117 [ 4] Litvin F L, Lian Q .Asymmetri c modified gear drives:reduc2 tion of noise, localization of cont act, simulation of meshing andstress analysis.Comput Methods Appl Mech Eng, 2000, 188:363 The analysis of teeth wear and flux for gear pump with ex ternal meshing and un￾symmetric teeth LI Wei, WANG Chengbing, WANG Xiaoqun Mechanical Engineering School, University of Science and Technology Beijing, Beijing 100083, China ABSTRACT A new ty pe unsymmetric gear pump w ith double pressure angles w as studied .New fo rmulas for the instantaneous flow and flow pulsation w ere put out .Compared with symmetric gear pump, the fo rmulas showed that the unsymmetric gear pump could efficiently improve flow pulsation w ith the rise of instantaneous flow .It is concluded that the sliding coefficient of unsymmetric gear pump w as smaller than that of symmetric gear pump .The increase of pressure angle of wo rk side w ould cause an evident increase in the minimum oil-film thickness and in the specific ratio of oil-film thickness, w hich is helpful to improve the lubricant characteristics of gear teeth surface .The practical significance of the present gear is demonstrated by the computer simulation w ith M ATLAB software, such predictions can provides the firm basis fo r the further engineering application of this new-type gear pump w ith unsymmetric teeth and double pressure ang les. KEY WORDS unsymmetric gear pump ;w ork principle;flow pulsation ;lubricant characteristics Vol.29 Suppl.2 李 威等:外啮合非对称齿轮泵优势分析 · 155 ·