MHYV 4*2*7/0.43 MHYVR 1*2*7/0.52煤矿用信号电缆 MHYV 4*2*7/0.43 MHYVR 1*2*7/0.52煤矿用信号电缆 MKVV|天津市电缆总厂第一分厂