US Patent 10971966 Power tool with partition assembly between transmission and motor

A power tool includes a tool housing and a motor assembly received in the tool housing. The motor assembly has a rear end portion, a front end portion, and a motor output shaft. A transmission housing is coupled to the motor housing with a transmission received in the transmission housing, to which the motor output shaft is drivingly coupled. A partition assembly includes a rear cover covering a rear end portion of the transmission housing that faces the front end portion of the motor. The rear cover of the transmission housing and the front end portion of the motor together define at least a first labyrinth path and a second labyrinth path therebetween configured to inhibit grease or dust migration between the transmission housing and the motor assembly.