Vacuum pump is one of the major noise sources affecting vehicle idle speed noise. In order to suppress this noise source and reduce the working noise of vacuum pump, the mounting bracket and rubber pad are abstracted as the spring series model of bracket vibration isolation rubber block bracket, and the influence of the vibration isolation system composed of mounting bracket and vibration reduction rubber block on the vibration transmission of vacuum pump during operation is further analyzed, When the vacuum pump works, the mounting bracket produces strong high-frequency vibration, and the vibration of the bracket causes large structural noise at the body connection, which is the main reason for the large working noise of the vacuum pump Secondly, the sealing condition of the whole vehicle is poor. After checking the sealing performance of the whole vehicle, it is found that: 1) There are no sound insulation and sealing measures for the engine compartment cover between the extended range engine compartment and the cab, and the noise generated during the operation of the vacuum pump is directly transmitted to the vehicle through the air; 2) There are many useless holes in the front compartment, middle passage, upper part of wheel side motor of rear axle and seat floor in the vehicle, which are not filled. In addition, the openings of steering gear, heating and air conditioning in passenger area and front wall harness are not sealed, and the vehicle is directly connected with the outside world; 3) The installation clearance between the cab door and the sliding door in the middle of the carriage is large, and the door is still connected with the outside after being closed. As shown in Figure 7, the poor sealing of the whole vehicle will reduce the sound insulation effect of the vehicle, and too much noise generated during the operation of the vacuum pump will be transmitted to the vehicle through the air, resulting in large interior noise Vacuum Pump Heat Treatment Guide,Heat Treatment Equipment Liquid Ring Vacuum Pump