As a convenient and efficient means of transportation, the drive system of gears and racks plays an important role in the design and manufacturing process of home elevators. In order to ensure the safety and stability of the elevator, there are a series of additional requirements that need to be met. This article will detail these requirements and analyze their importance and how to implement them.
General. According to the requirements, the home elevator should be driven by one or more motors and the car should be supported, lifted and lowered by gears meshed with the rack. In addition, measures need to be taken to prevent foreign matter from entering the drive gear or between the safety gear and the rack.
Load distribution. When multiple drive gears engage with the rack, an automatic adjustment device needs to be set up to distribute the load efficiently, or the drive system needs to be designed to accommodate the load distribution between the gears under normal conditions.
Cogs. The design of the drive gear should meet certain safety factor requirements. The minimum factor of safety relative to the bending fatigue strength limit of the teeth should be 2, while the minimum factor of safety of each gear relative to the contact fatigue strength limit should be 15。These safety factors are set to take into account the dynamic loads, wear and fatigue that may occur during the design life of the drive gear and its associated components. In addition, root cutting of the teeth needs to be avoided and the gears should be fixed to the output shaft without slippage and wear.
Rack. The fastening and attachment of the rack should be reliable and need to be properly straightened to prevent incorrect engagement or damage to the teeth. The rack should be made of a material with the friction characteristics that match its meshing gear and be designed in accordance with the requirements of the relevant standard. If the rack is subjected to a pressure load, the minimum bending safety factor should be 3. Taking into account the maximum wear, the minimum safety factor of the rack with respect to the static strength limit of the gear teeth should be 2.
Meshing of gears and racks.
In order to guarantee the correct engagement of the rack with each drive gear and the gear of the safety device under any load conditions, corresponding measures need to be taken. These measures should not rely on car guide shoes. The correct gear and rack meshing should be tangent between the pitch circle of the gear and the pitch line of the rack, and the deviation between the pitch circle of the gear pitch circle and the rack and pinion line should not be greater than 1 3 of the modulus. If the above method fails, further measures should be taken to ensure that the deviation between the gear pitch circle and the rack and pinion line should not be greater than 2 3 of the modulus. In addition, it is necessary to ensure that the rack meshes with the entire tooth profile of the gear along the entire tooth width. If the above measures fail, at least 90% of the rack width should be meshed with the gear profile. Premium short** plan