【正文】 ents axis 0 angular velocity, and 1 i20 represents total drive ratio from axis 2 to axis 0 including differential gear train and reducing unit II when axis 1 (servomotor axis) is fixed. The conventional motor’s and servomotor’s influence on the output motion. When the conventional motor and the servomotor run at the same time through the position of the differential gear train, the output velocity can be expressed as . Because the servomotor can run at arbitrary angular velocity between the zero and specific velocity in both positive and negative directions, n2 can be expressed as .where K is the ratio of the actual angular velocity to the specific angular velocity of the servomotor。 2 School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China The problems of hybrid input of mechanical press are studied in this paper, with differential gear train as transmission mechanism. It is proposed that “adjustablespeed amplitude” or “differentialspeed ratio” is the important parameters for the hybrid input mechanism. It not only defines the amplitude of the adjustable speed, but also determines the ratio of the power of the servomotor to the power of the conventional motor. The calculating equations of the ratio of transmission in all axes, the power of two motors, and the working load distribution are deduced. The two kinds of driving schemes are put forward that the servomotor and the conventional motor simultaneously drive and the servomotor and the conventional motor separately drive. The calculating results demonstrate that the latter scheme can use much lower power of the servomotor, so this scheme makes manufacture and use cost much lower. The latter scheme proposes a feasible way to apply the hybrid mechanism of mechanical press in practice engineering. mechanical press, hybrid mechanism, differential gear train, adjustablespeed 1 Introduction At present there are many research papers about the hybrid mechanism of mechanical press, and it has bee a hot research topic. The hybrid mechanism is a mechanism with 2degreeof freedom (also called differential speed mechanism), and when two independent motions are input at the same time, the output that can satisfy some motion requirements is obtained through the motion position of the mechanism. The hybrid mechanism is also called controllable mechanism, or hybrid machine. The purpose of research on hybrid mechanism of mechanical press is using conventional motor with big power carrying flywheel to finish stamping work pieces。 中文 4340 字 出處： Science in China Series E: Technological Sciences February 2020, Volume 50, Issue 1, pp 6980 Study of utilizing differential gear train to achieve hybrid mechanism of mechanical press HE YuPeng1?, ZHAO ShengDun2, ZOU Jun2 amp。 and uses ser — vomotor with low power to adjust the slider speed. The advantages of the hybrid mechanism applied in the mechanical press are that it not only can reduce much lower manufacturing cost than servo press, but also has a flexible working velocity of slider[1]. So the mechanical press of hybrid mechanism arouses many researchers’ interest in working on it。 the value is arbitrary between ?1 and +1, including zero. n2e is the specific angular velocity of the servomotor. Adjustablespeed amplitude and differentialspeed ratio Adjustablespeed amplitude. In order to correctly denote the variable velocity of the differential gear train of the hybrid mechanism, the concept of adjustablespeed amplitude is introduced. As shown in Figure 1, adjustablespeed amplitude is the ratio (or percentage) of absolute value of up and down adjustable amount to the base speed. In the differential gear train of the hybrid mechanism, the adjustablespeed amplitude equals the ratio value of axis 0 output speed of operating a single servomotor at the specific speed to axis 0 output speed of operating a single conventional motor[13]. In the differential gear train of the hybrid mechanism, the adjustablespeed amplitude is the most basic and the most important technology parameter. It not only determines the matching relationship of the speed of the two input axes, but also decides the matching relationship of the installed capacity of the servomotor and the conventional motor Differentialspeed ratio. The differentialspeed ratio is usually used to express adjustable speed technology performance in the differential gear train. It is an important technology parameter of the differential effect in the differential system. The differentialspeed ratio equals the reciprocal value of the adjustablespeed amplitude. It can be expressed as According to the fact that the angular velocity is in inverse proportion to its torque and that the same loa