The internal components of hydraulic chain hoists in coal mines typically include the following:

1. Motor: The motor provides power for the hydraulic chain hoist, driving the hydraulic pump to generate the necessary hydraulic pressure.

2. Hydraulic Pump: The hydraulic pump converts the mechanical energy provided by the motor into hydraulic energy, pushing the hydraulic oil through the hydraulic system.

3. Hydraulic Cylinder: The hydraulic cylinder is a key component of the hydraulic system, converting the hydraulic energy into mechanical energy to drive the chain hoist mechanism.

4. Chain Hoist Mechanism: This mechanism typically consists of a sprocket, chain, and hook. The sprocket engages with the chain, which is connected to the hook used for lifting and moving loads.

5. Control Valve: The control valve regulates the flow of hydraulic oil, controlling the movement and direction of the chain hoist.

6. Oil Tank: The oil tank stores the hydraulic oil, ensuring a sufficient supply for the hydraulic system.

7. Filters and Coolers: Filters remove contaminants from the hydraulic oil, while coolers help maintain the optimal operating temperature of the hydraulic system.

These internal components work together to enable the hydraulic chain hoist to lift and move heavy loads safely and efficiently in coal mine environments. Proper maintenance and inspection of these components are crucial to ensure reliable and safe operation.