Ratchet-shaped hydraulic tensioner

Abstract

The invention discloses a ratchet-shaped hydraulic tensioner which comprises a shell, a one-way valve and a piston. The shell is provided with a containing cavity, an oil inlet is formed in one end ofthe shell, and the end, close to the oil inlet, of the containing cavity communicates with the oil inlet. The end, away from the oil inlet, of the containing cavity is opened towards the outside of the shell, the one-way valve is fixedly arranged in the oil inlet, and the piston is contained in the containing cavity. The piston and the containing cavity are in clearance fit, and the piston can doreciprocating motion in the axial direction of the containing cavity. A compressed spring is arranged in the containing cavity, one end of the compressed spring is in contact with the piston, and theother end of the compressed spring is in contact with the bottom face of the containing cavity. A locking spring is further included. A ratchet section is arranged on the piston, the ratchet sectionis located at the end, away from the compressed spring, of the piston, the locking spring is in contact with the ratchet section, and therefore the piston can only move in the direction away from thecompressed spring.

Description

technical field [0001] The invention belongs to the technical field of hydraulic tensioners, in particular to a ratchet-shaped hydraulic tensioner. Background technique [0002] The tensioner acts on the timing belt or timing chain of the engine, guiding and tightening it, so that it is always in the best tightening state. Generally, there are two methods: hydraulic and mechanical, both of which can automatically adjust the tension of the timing belt and the timing chain. The specific distance is: under the transmission of the timing belt or timing chain, the camshaft drives the valve to open and close at the correct time, and cooperates with the piston to complete the four processes of intake, compression, work and exhaust. Because the timing belt and timing chain will jump when running at medium and high speeds, and the timing belt will be elongated and deformed due to the material and force of the belt during long-term use, resulting in jumping teeth, resulting in inaccu...

AI Technical Summary

Problems solved by technology

[0004] The traditional hydraulic tensioner drives the oil pump to build up a certain oil pressure through the operation of the engine, and the oil pressure is passed into the hydraulic tensioner to push the piston out, so that a certain pressure is applied to the belt or chain through the piston, so as to ensure the tension of the belt. Or the chain is tightened; but one problem that it cannot overcome is that after the oil pressure of the piston of the hydraulic tensioner disappears after the engine stops, the piston will retract into the housing under the push of the belt or chain. It takes a certain amount of time to drive the oil pump to start rotating to build up enough oil pressure, that is to say, it will be difficult for the piston of the hydraulic tensioner to stretch out to apply force to the belt or chain during the period from the start of the engine to normal operation and the establishment of enough oil pressure. Sufficient pressure, that is to say, it is difficult to ensure that the belt or chain has sufficient tension, so it is very easy to cause the problem of inaccurate gas timing caused by jumping teeth

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