Structural Analysis and Characteristics of Balanced Compound
Gear Motors 栾 Zhenhui, Pang Shiguo (Huainan Institute of Technology, Huainan, Anhui 232001, China) features simple structure, radial hydraulic pressure balance and small torque ripple, which can be widely used in mining machinery and engineering machinery. Good prospects for promotion and application.
The
Gear Motor has the characteristics of simple structure, small volume, light weight, convenient use and maintenance, reliable operation, low price and insensitivity to oil pollution, and thus is widely used in various mining machinery and engineering machinery. The main disadvantage of gear motor is that the radial hydraulic pressure is unbalanced, the bearing wear is serious; the output torque and the rotational angular velocity are pulsating, causing system vibration and noise; the starting torque is small and the low speed stability is poor. In addition, its displacement is not adjustable and the scope of use is limited. In order to solve the above problems, this paper proposes a balanced composite gear motor and its structural principle.
1 Working principle The structural principle of the balanced composite gear motor is mainly composed of the center wheel A, the planetary gear (idler wheel) B, the internal gear C, the sealing block D and the front and rear end covers. Gears A, B, and C meet the basic conditions of planetary gear transmission. The gears A and B constitute an external gear motor, and the gears B and C constitute an internal gear motor. Therefore, it is called a compound gear motor. Since the motor inlet and outlet ports are symmetrically distributed with respect to the gears A, B, and C, the radial hydraulic pressure on each of the gears is balanced, so the motor is also referred to as a balanced compound gear motor (referred to as a composite gear motor).
Assume that the center of rotation of the planetary gear B is fixed. When the high-pressure liquid enters the P-cavity, the central wheel A rotates clockwise under the action of the pressure difference on both sides of the gear teeth, and the low-pressure oil is discharged from the T port. Composite gear motor. If the internal gear C is fixed, the planetary gear rotates to form a planetary compound gear motor; if the internal gear is not fixed and the center of rotation of the planetary gear is not fixed, a differential compound gear motor is constructed.
National Natural Science Foundation of China (Grant No. 9575010) 2 Theoretical Torque This article discusses the fixed-shaft compound gear motor as an example. For the sake of simplicity, it is set as a standard gear and an open symmetric double unloading groove.
The theoretical displacement of the average theoretical torque compound gear motor is: Za, Zb - the number of teeth of the gears A, B; the speed of the na, nb gears A, B.
Therefore, the theoretical torque of the compound gear motor is: instantaneous theoretical torque. The instantaneous flow of each external gear motor in the composite gear motor is 2/i - the distance of the i-th external gear motor instantaneous meshing point to the node; - center wheel, idle Wheel circle (division circle) radius; ha, hb center wheel, idler tooth tip height, ha = hb = m; Wa - center wheel angular velocity.
The instantaneous flow rate of each internal gear motor in the compound gear motor is: Rc - internal gear pitch circle (division circle) radius; - internal gear teeth number; / i - i - i internal gear motor instantaneous meshing point to node distance ;W—Idle wheel angular velocity, Whc internal gear tooth tip height, hc=m. The instantaneous flow rate of the composite gear motor can be determined by the formula: Therefore, the instantaneous torque of the composite gear motor is: the torque unevenness coefficient is defined as: M know, compound The instantaneous output torque of the gear motor is determined by / and /, that is, the distance from the instantaneous meshing point to the node. Known by the involute property, / and / can be obtained from the instantaneous angular distance 屯 and Y of the front wheel line of the driving wheel and the intersection of the indexing circle and the node.
3) It is related to whether Z can be divisible by 3, and Y is related to whether zb can be divisible by 2.
3 Characteristic Analysis In the composite gear motor, since the inlet and outlet ports are symmetrically distributed with respect to the respective gears, the radial fluid pressures of the main components are balanced, so the bearing load is small and the motor has a long service life.
The compound gear motor has 2x high pressure chambers and low pressure chambers respectively, and its displacement is 2x times that of ordinary gear motors, so its output torque is also 2x times higher than that of ordinary gear motors. Reasonably selecting the number of teeth of each gear and shifting 2x meshing points from each other can significantly reduce the output torque ripple and rotational angular velocity pulsation of the motor.
The compound gear motor can be directly matched with oil through the housing, so the oil distribution method is simple and easy to implement, and the axial force is balanced.
Adjusting the speed of the internal gear can change the displacement of the motor and thus change the output speed of the motor.
