【正文】 he two motors as well as the optimal design. The trajectory planning based on polynomial interpolation is also investigated, and the puter simulation shows that the result is indeed attractive. In addition, Meng[3] has also investigated the kinematical analysis of the sevenbar mechanism, and the optimal design has been pleted based on the minimum power of the servomotor motor, and Meng has proposed that the hybrid mechanism is a research direction of the mechanical press. Tokuz[4] first put forward of the hybrid mechanism and analyzed the velocity synthesis by using the differential gear train. His experiment confirmed the feasibility of his conception. The concepts of the adjustablespeed amplitude and differentialspeed ratio are not mentioned in their works, and the relationship between the velocity variation and the power of the two motors were not clearly given[5― 8]. But these concepts are very important and absolutely necessary for the hybrid mechanism to select the two motors’ power and determine the working load distribution between conventional motor and the servomotor. In refs. [1― 3] they used linkage mechanism to implement the hybrid input of mechanical press. The method is very plex because the change of the length and position of the each bar in linkage mechanism will have an effect on the motion of the slide of the mechanical press. So some principal problems are usually ignored in research hybrid mechanism course, and the research results don not always coincide with the practice engineering conditions[9― 11]. The gear differential train has two freedoms, and the ratios of transmission between arbitrary two axes are a constant. In order to simplify the mechanical model and make the problems much projected, the differential gear train is used as transmission mechanism to study the hybrid problems of the mechanical press in this paper. This paper addresses the relationship between the adjustablespeed amplitude and the power of the two motors, the working load distribution between the two motors, and puts forward two drive schemes of the conventional motor and the servomotor simultaneously working, and two motors separately working. With the 200ton mechanical press as the engineering background, a drive system of the hybrid mechanism of the mechanical press is designed, and the feasibility of the two drive schemes in mechanical press is analyzed. 2 The principle of the hybrid mechanism The working principle of the hybrid mechanism of the mechanical press with differential gear train is illustrated in Figure 1. The system consists of conventional motor (also called AC machine with constant speed), servomotor, reducing unit I, reducing unit II, differential gear train, and crank slide mechanism. The output axis of the differential gear train is connected with the crankshaft of the crank slide mechanism. One of the two input axes links the conventional motor through the reducing unit ?。 and (ii) the conventional motor and the servomotor are separately driven. The conventional motor and the servomotor being simultaneously driven. This scheme shows that the angular velocity of the crankshaft of the mechanical press is posed of the angular velocity of the conventional motor as the basic speed and the angular velocity of the servomotor as the adjustable speed (Figure 3). The angular velocity and the powers can be calculated by using eqs. (1)― (18). The conventional motor and the servomotor being separately driven. This scheme shows that only one motor is driven in the hybrid input course and at the same time another motor is braked, . when the crankshaft is in differential running stage, the conventional motor and the servomotor are separately operated。它建議將“調(diào)速幅度”或“差動(dòng)速比”作為重要參數(shù)混合投入機(jī)械研究中。計(jì)算結(jié)果表明后者的方案能比伺服電機(jī)使用更低的功率，因此這種方案能使得制造和使用成本低得多。混合動(dòng)力機(jī)制也可稱為可控機(jī)制，或者稱作混合機(jī)器。杜和郭已經(jīng)全面討論了七桿的機(jī)械壓力機(jī)的混合機(jī)制，包括組成連桿機(jī)構(gòu)的可行條件，滑塊機(jī)構(gòu)的動(dòng)力分析，和兩臺(tái)電機(jī)之間轉(zhuǎn)矩和功率的分配以及它們之間的優(yōu)化設(shè)計(jì)。他的實(shí)驗(yàn)證實(shí)了他的理論的可 行性。這種方法相當(dāng)復(fù)雜，因?yàn)檫B桿機(jī)構(gòu)每根連桿的長(zhǎng)度和位置的改變會(huì)對(duì)機(jī)械壓力機(jī)的滑塊運(yùn)動(dòng)產(chǎn)生影響。這篇文章討論了兩電機(jī)調(diào)速幅度和功率之間的關(guān)系，兩電機(jī)之間的工作負(fù)載分配，并且提出了傳統(tǒng)電機(jī)和伺服電機(jī)同時(shí)工作、分開(kāi)工作的兩種驅(qū)動(dòng)方案。差動(dòng)輪系的輸出軸由曲柄滑塊機(jī)構(gòu)的曲柄軸連接而成。傳統(tǒng)電機(jī)的角速度是一個(gè)常數(shù)，所以它的價(jià)格更便宜。因此它既可以節(jié)約機(jī)器制造代價(jià)又可以節(jié)約機(jī)器運(yùn)轉(zhuǎn)成本。當(dāng)機(jī)械壓力機(jī)的滑塊接近工作起點(diǎn)時(shí)，它的速度會(huì)從高速變成 低速，然后以低速（稱作低速進(jìn)給階段）沖壓工件。速度 V1和 V3應(yīng)該盡可能一樣快，速度 V2 應(yīng)該緩慢、靈活，目的是為了確保機(jī)械壓力機(jī)每分鐘的工作次數(shù)并能滿足不同技術(shù)的要求。三根軸的角速度分別為 n1,n2 和 n3。 圖 2 滑塊的理想核心位置 常規(guī)電機(jī)對(duì)輸出 運(yùn)動(dòng)的影響 當(dāng)伺服電機(jī)停止運(yùn)動(dòng)時(shí)， n2=0，只有常規(guī)電機(jī)的角速度 影響輸出的角速度 n0。當(dāng) K 是伺服電機(jī)的實(shí)際角速度和特殊角速度之比時(shí)，數(shù)值相對(duì)的在 1左右或 +1，包括 是伺服電機(jī)的特殊角速度。 在混合機(jī)械的差速齒輪中，調(diào)速振幅是最基本和最重要的技術(shù)參數(shù)。差速齒輪比等于調(diào)速振幅的倒數(shù)值。因此當(dāng)輸出角速度在不同的工作區(qū)域運(yùn)行時(shí)，兩個(gè)電機(jī)載荷之比也不同。因此常規(guī)電機(jī)承受 %—— 100%的工作載荷，伺服電機(jī)僅承受 0—— %的工作載荷。根據(jù)方程（ 9）和（ 10）， P1 是負(fù)值。輸出速度的減小是以消耗伺服電機(jī)的輸入功率來(lái)衡量的。當(dāng)常規(guī)電機(jī)或伺服電機(jī)驅(qū)動(dòng)時(shí)，或同時(shí)驅(qū)動(dòng)它們時(shí)，機(jī)械壓力機(jī)的曲柄滑塊可以獲得差動(dòng)角速度。靈活的低速運(yùn)行，當(dāng)常規(guī)電機(jī)制動(dòng)，伺服電機(jī)運(yùn)行時(shí) ,n1=0。曲柄軸有兩個(gè)旋轉(zhuǎn)方向；因此它很靈活。5 總結(jié) 根據(jù)機(jī)械壓力機(jī)的速度特征，差速齒輪系可以應(yīng)用在混合壓力機(jī)的混合機(jī)械中。所以增加了制造成本和機(jī)械壓力機(jī)的運(yùn)行代價(jià)，因此在實(shí)際應(yīng)用中是無(wú)效的。