Common Problems And Treatment of Gearbox (Part 2)

Gear box oil temperature is too high

1 Possible air cooler failure

1. The failure of the air cooler itself

If the wire is short-circuited, disconnected, or the motor burned out, the fan will not run.

2. Dust affects the cooling of the air cooler

A large amount of dust on the heat sink will affect the heat dissipation of the air cooler, resulting in insufficient cooling of the lubricating oil.

3. The wiring of the air cooler is wrong

Incorrect wiring will cause the fan to reverse, which will cause the wind direction to reverse and affect heat dissipation.

2 The oil pipe of the lubrication system to the oil distributor and cooler is reversed

The two outlets of the filter are marked to the gear box or to the cooler. When the temperature is low, it directly enters the oil distributor, and when the temperature is high, it enters the cooler. If the oil pipe is reversed, the high-temperature oil will not be cooled by the cooler, and the oil temperature will inevitably be too high. It can be solved by installing the oil pipe according to the correct requirements.

3 The pressure valve or temperature control valve of the lubrication system is wrong

Under the condition that the filter is connected to the gear box oil pipe correctly, when the oil temperature exceeds 55°C, the pipe from the filter to the oil distributor still has oil flowing (judgment method: you can touch the oil pipe, such as the temperature is consistent with the temperature of the distributor Or there is a sense of vibration of oil flow, which means that there is oil flowing through the oil pipe), indicating that there is a problem with the temperature control valve of the filter. You can consult the lubrication system manufacturer or the technical department to replace the temperature control valve. If it is Inde Norman's pressure valve problem, it will be more difficult, and it needs to be solved by several parties.

Gear Box

4 overflow valve problem

As a pressure relief element, the relief valve should only take effect when the oil temperature of the gearbox is low and the pressure is high. At present, it is found that the oil valve with high oil temperature still flows, so that the amount of oil after cooling will be reduced, and some of the oil will be directly returned to the gear box without cooling, resulting in insufficient overall cooling and high oil temperature. If the oil temperature is high and the pressure is low, and the overflow valve opens again, you should contact the lubrication system manufacturer as soon as possible.

High temperature shaft bearing temperature is too high

1 Insufficient oil intake of bearing

Open the rear box observation cover to check the oil outflow of the bearing. If there is little oil out, it means that the oil intake of the bearing is insufficient. There are four main reasons:

1) Too small oil inlet design leads to insufficient oil inlet;

2) The oil inlet of the box is misaligned with the oil inlet of the oil ring;

3) The oil hole is blocked by impurities and the amount of oil is reduced;

4) The oil passage of the oil inlet hole is not drilled.

Check whether it is the above reason according to the actual situation, and take corresponding measures.

2 Bearing radial clearance is too small

The operation of the bearing must ensure a certain radial clearance. When the clearance is too small, it will cause the phenomenon of stagnation of the roller and the raceway, and a large amount of heat will cause the temperature to rise. This situation is relatively rare, you can use a feeler gauge to detect the radial clearance of the upper end of the bearing.

3 Gear injection is insufficient

Insufficient oil injection of the gear or misalignment of the oil holes with the gear will cause the gear temperature to be high, and then the heat will be transferred to the bearing closer to the gear to make the bearing temperature higher.

4 Oil temperature is too high

In the case of insufficient cooling, the oil temperature is too high, so that the high-speed bearing temperature cannot be effectively removed, resulting in excessive bearing temperature.

5 Oil temperature is too low

If the oil temperature is too low, the temperature of the high-speed shaft bearing is also too high. The lubricating oil has a high viscosity at low temperatures, and the oil passing through the oil inlet will become very little. The capacity will also be much worse, leading to higher and higher bearing temperatures, causing a vicious cycle.

This situation is mainly reflected in the winter and the cast iron gear box of the water-cooled lubrication system (for example, the case of the high temperature of the FL2000H bearing of the sea-mounted Phaeton Schiller).

6 Bearing damage

The damage of the bearing will make the roller run unevenly, especially the high-speed shaft bearing will generate a lot of heat when the rotation speed is very high.

7 Friction or excessive packing

Interference friction of parts and over-tightening of packing will generate a lot of frictional heat and increase the bearing temperature.