Fully variable electro-hydraulic valve system having buffering function

A fully variable electro-hydraulic valve system having a buffering function, comprising:

• a camshaft and a valve assembly;
• a sliding sleeve, a spiral shaft, a piston and a position restoring spring, wherein the sliding sleeve is fixed relative to an engine;
• the spiral shaft and the piston are connected to the sliding sleeve in a sliding sealing manner;
• an inner cavity between the spiral shaft and the piston is referred to as a sliding sleeve cavity;
• the position restoring spring is clamped between the spiral shaft and the piston;
• the piston abuts against the valve assembly;
• and the spiral shaft is controlled by a cam surface of the camshaft in the axial direction;
• wherein the spiral shaft has a first end and a second end which are oppositely disposed;
• a spiral surface is provided at the first end;
• the second end is in transmission connection with a gear-rack mechanism;
• the gear-rack mechanism comprises a control gear and a rack;
• the control gear is arranged at the second end of the spiral shaft;
• and the rack is driven by a linear actuator controlled by an electric control unit of the engine;
• wherein an oil inlet hole and a limiting oil hole are formed in the sliding sleeve and communicate with a low-pressure oil circuit of the engine;
• a one-way valve is arranged on a connecting pipeline between the oil inlet hole and the low-pressure oil circuit of the engine;
• wherein a step hole structure is provided at an end, where the piston is located, of the sliding sleeve and comprises a large hole and a small hole;
• the small hole is matched with a sliding sealing surface of the piston;
• a buffering ring is arranged in the large hole;
• the buffering ring sleeves the sliding sealing surface of the piston and is in sliding sealing fit with an inner circumferential surface of the large hole;
• the buffering ring and the piston form a buffering cavity in the step hole;
• a flange used for colliding with the buffering ring when a valve of the valve assembly is seated is arranged on a circumferential surface of an outer end of the piston;
• a baffle plate is mounted at the end, where the piston is located, of the sliding sleeve;
• and when the valve of the valve assembly is closed, a buffering distance is reserved between the buffering ring and the baffle plate;
• and
• wherein a buffering oil hole communicating with the buffering cavity is formed in the sliding sleeve;
• and the buffering oil hole communicates with the low-pressure oil circuit of the engine by means of a throttling device.