Troubleshooting of equal gear failure of the hotte

Troubleshooting of bulldozer's "equal gear" fault

Guide: there is a TY220 bulldozer. After working for about 2000h, it has the phenomenon of equal gear after startup, that is, the machine does not walk after engaging in gear, and it needs to operate for 6~10min before walking, or it can walk after manual exhaust from the pressure tap of the secondary filter of the variable speed oil circuit, and everything works normally after walking

there is a TY220 bulldozer. After working for about 2000h, it appears the phenomenon of "equal gear" after startup, that is, the machine does not travel after gear is engaged, and it needs to operate for 6~10min before it can travel, or it can only travel after artificial exhaust from the pressure tap of the secondary filter of the variable speed oil circuit, and everything works normally after walking

the essence of "equal gear" is that the oil pressure is not established in time. The main reason why the oil pressure cannot be established in time is that the variable-speed pump is empty, that is, there is air in the oil suction circuit of the variable-speed pump, so the variable-speed pump exhausts while discharging oil during operation. The oil pressure can be established only when the air in the oil suction circuit is exhausted and the variable-speed pump is no longer empty. The reasons for the empty suction of the variable speed pump may be: poor sealing of the pipe joint in the oil suction circuit; The oil suction hose is damaged; The oil seal of the transmission pump frame is damaged. It can provide good shock absorption (double density tire structure can even improve the shock absorption performance by 30%)

according to the principle of "from simple to complex", we checked the machine one by one. First, the O-ring of the strainer and the oil suction port of the variable speed pump was checked and replaced, but the fault was not eliminated; The oil suction hose of the variable speed pump was also checked, and the pressure test was carried out on the oil suction hose. The results showed that the hose was not damaged; Then the variable-speed pump was disassembled and inspected, and it was found that the skeleton oil seal was not damaged. For the sake of insurance, we replaced a new variable-speed pump, but the fault Figure 3 total posterior spine system has not been eliminated. Finally, it was found that there were traces of oil leakage at the oil suction port of the steering pump, which was caused by the loose fastening bolts of the oil pipe after inspection; Therefore, the O-ring of the oil suction port of the steering pump was replaced, and the oil suction pipe of the steering pump was checked and tightened. As a result, the fault of "equal gear" was eliminated

the material testing machine is the product of the combination of modern electronic technology and mechanical transmission technology. The analysis shows that the variable speed oil circuit and steering oil circuit of the machine share a coarse filter, and the oil suction port of the steering pump is lower and the oil suction port of the variable speed pump is upper; When the suction line of the steering pump leaks, another policy worthy of close attention after shutdown for a period of time makes there is no oil in the primary filter, so the variable speed pump is empty when starting, which is the real reason for the "equal gear" of the machine