| Continuously Variable Transmission(CVT)that can make the output angular velocities continuously change with certain control function is an important transmission mode,which has many advantages,such as working reliability,steady capability of variable transmission and low cost,etc.However,the high pulsation rate and the inertia force are difficult to balance in the traditional Pulsation CVT(P-CVT),as the pure connecting rod mechanism is adopted.At the same time,the existing combined P-CVT is too large on account of a few phases of transmissions arranged in a number of parallel planes.Therefore,the research and development of new transmission mechanism of P-CVT is of significance in solving the above problems from principle.Based on the study of some existing transmission modes of P-CVT,the kinematics and dynamics characteristics of a new type of combined transmission mechanism of pure mechanical P-CVT are studied by means of theoretical research,numerical calculation,prototype trial-manufacture and test verification.Firstly,the kinematics mathematical model of key components in single-phase transmission mechanism is established based on the complex vector method,then the method of optimizing phase number in multi-phase transmission mechanism is put forward,and the flow chart of optimizing phase number is designed.Secondly,through the numerical calculation of the mathematical model,the kinematic characteristics of the transmission about a certain type of rod-gear type P-CVT are analyzed,the optimal phase number and the optimal output angular velocitiy regulation mode of the mechanism are determined,and the law of the variation of the transmission ratio and the pulsation rate with the eccentricity is summarized.It is proved theoretically that the new type of P-CVT has the characteristics of low pulsating rate,large transmission ratio and variable interval width of transmission ratio.Thirdly,the dynamic mathematical models of single-phase transmission mechanism,multi-phase transmission mechanism and the key components are constructed based on the principle of D’Alembert respectively,and the motion equation of multi-phase transmission mechanism is constructed,based on the law of conservation of mechanical energy.At the same time through numerical calculation,the dynamic characteristics of the key components in the eight-phase transmission mechanism of the certain type of rod-gear type P-CVT are studied.Finaly,A prototype about rod-gear type P-CVT is developed,and the test system for monitoring input,output angular velocity,torque and other parameters is established.It is proved that the transmission mechanism has the transmission characteristics of small pulsation and large transmission ratio.The main innovation is as follows:(1)Based on the principle of complex vector method,many kinematics mathematical models of key components in single-phase transmission mechanism are constructed,such as connecting rod,rocker and pin,etc.The kinematics characteristics of key components about the certain rod-gear P-CVT are analyzed,and the transmission characteristics are achieved.(2)Based on the principle of D’Alembert,the dynamic mathematical models of single-phase transmission mechanism,multi-phase transmission mechanism and key components are established respectively,through the analysis study on the dynamic equations,the dynamic characteristics of the certain rod-gear P-CVT are achieved.(3)A test-bed for the certain rod-gear P-CVT is built,through the experimental study on the prototype of the certain rod-gear P-CVT,the correctness of the conclusions obtained from theoretical analysis and simulation calculation is verified.Through the theoretical analysis and Experimental Research on the transmission mechanism of a new type rod-gear CVT,it is obviously that the transmission has the advantages of small volume,low pulsation rate,large transmission ratio and wide range of change in transmission ratio,etc. |
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