带式输送机已广泛应用于煤炭、化工、冶金、建筑等行业。而下运皮带机是用于“向下倾斜运输物料”特定场合的皮带机。它具备以下特点:(1) 当向下倾角β=3°～5°时,因物料的纵向重力分力与胶带承载分支和空载分支的阻力相平衡,因此,这时的牵引力W_0≈0;但是当输送机处于空载运行时,其牵引力W_0>0。(2) 当向下倾角β>6°时,W_0<0。因此,重载运行的输送机应在制动状态下运转。现在下运皮带机(在煤矿称为“下山”皮带机)的传动装置仍普遍采用通用的齿轮减速器,当重载运行时常会出现“飞车”现象,这是很危险的。即使加上了电磁制动器,往往也无济于事。因此,它严重威胁着 Belt conveyor has been widely used in coal, chemical, metallurgical, construction and other industries. The lower conveyor belt is used to “tilt the material” specific occasions belt machine. It has the following characteristics: (1) When the downward inclination β = 3 ° ~ 5 °, due to the vertical component of the material force and the load carrying tape and no-load branch balance of resistance, so the traction W_0 ≈ 0 ; However, when the conveyor is in no-load operation, its traction W_0> 0. (2) W_0 <0 when downtilt β> 6 °. Therefore, heavy-duty conveyors should be operated in a braking state. Nowadays, the common gear reducer is commonly used in the transmission of a conveyor belt conveyor (which is called a “downhill” belt conveyor in a coal mine). It is very dangerous when a heavy-duty running vehicle often has a “flying car” phenomenon. Even with the electromagnetic brake, often helpless. Therefore, it is a serious threat