Clutch piston oil pressure balance mechanism suitable for large-torque commercial vehicle gearbox

The invention discloses a clutch piston oil pressure balance mechanism suitable for a large-torque commercial vehicle gearbox. The clutch piston oil pressure balance mechanism is characterized in thata piston oil cavity (7) is formed between a clutch hub assembly (1) and a piston (2), a balance piston oil cavity (8) is formed between the clutch hub assembly (1) and a balance piston (3), main oilpath oil pressure (12) passes through a first oil hole (10) and an oil guide cover (4) to enter the piston oil cavity (7), and lubricating oil (11) enters the balance piston oil cavity (8) through a second oil hole (9). According to the clutch piston oil pressure balance mechanism, the second oil hole allowing the lubricating oil to be injected is additionally arranged at the position, corresponding to the balance piston oil cavity, of a shaft so that when a clutch rotates at a high speed, the lubricating oil can enter the balance piston oil cavity under action of centrifugal force to eliminate the influence of centrif