ZQDR—410型牵引电动机(简称410电机,下同)的换向器侧端盖(称小端盖,下同)在运用中经常发生辐板断裂或贯穿性裂纹。迄77年6月统计,各段共有49起,严重地影响了东风_4型内燃机车的行车安全。调查资料表明,出现上述故障的电机有半数以上是第2位和第5位的,断裂端盖辐板的厚度在8～12毫米范围内,裂纹全是沿端盖内侧工艺凹台加工元角处发展,在机车运用7～15万公里后产生(见本刊77年第5期)。通过对断裂 ZQDR-410 type traction motor (referred to as the 410 motor, the same below) commutator side cover (called the small end cover, the same below) often occur in the use of plate fracture or through cracks. As of June 77 statistics, a total of 49 paragraphs, a serious impact on the Dongfeng _4 type locomotive driving safety. Survey data show that more than half of the motor appears above the fault is the second and fifth bit, the thickness of the fracture of the end cover plate in the range of 8 to 12 mm, the crack is all along the inside of the end cap processing recess processing unit angle Department of development, the use of locomotives after 7 to 150,000 km (see publication No. 5 of 77). Pass on the break