Air pumping type hydraulic tensioner

Abstract

The invention provides an air extracting hydraulic pressure tension device, which can simply extract air which enters into a casing main body, hold an air extracting unit with high pressure state in ahigh pressure oil chamber to simply and fixedly mounted in the casing main body, an air extracting unit (250) of an air extracting type hydraulic pressure tension device (200) comprises a single wayball valve (251) which extract air which enters into a high pressure oil chamber (R), a baffle (252) which contains the single way ball valve (251) and leads the single way ball valve to walk betweena flow-in lateral and a flow-out lateral, a cylindrical ball seat (253) which is inserted in an air extracting lateral which is fixed on the front end of the baffle (252), prevents pressure oil in thehigh pressure oil chamber (R) from flowing out when the single way ball valve (251) is sited and is communicated with an air outlet (222) of a plunger piston (220), and a spring for loading the ballvalve which loads the single way ball valve (251) towards the cylindrical ball seat (253).

Description

technical field [0001] The present invention relates to a hydraulic tensioner for applying appropriate tension to, for example, a timing belt or a timing chain of a vehicle engine. Background technique [0002] In general, a hydraulic tensioner equipped with a spherical check valve mechanism that prevents the reverse flow of pressure oil in the high-pressure oil chamber is widely used on the timing belt or timing chain that transmits rotation between the crankshaft and camshaft of the vehicle engine. . [0003] Conventionally, as such a hydraulic tensioner equipped with a spherical check valve mechanism, there are such Figure 8 As shown in , there is a cylindrical plunger 520 protruding freely from the plunger sliding hole 511 formed in the housing main body 510 toward the traveling chain, and is sandwiched between the aforementioned plunger sliding hole 511 and the plunger. The plunger loading mechanism 530 that loads the plunger 520 in the direction in which the plunger ...

AI Technical Summary

Problems solved by technology

[0005] However, although the hydraulic tensioner 500 of the prior art disclosed in the aforementioned Japanese Patent Laid-Open No. 11-336855 can rely on the check valve unit 540 to prevent the reverse flow of the pressure oil flowing into the high-pressure oil chamber R, sometimes the air and Pressure oil is mixed into the high-pressure oil chamber R of the housing body 510 from the pressure oil supply source not shown together, and the high-pressure state in the high-pressure oil chamber R cannot be maintained due to the mixed air. There is a problem that the traveling chain shakes due to the influence of the air mixed in the high-pressure oil chamber R at the time of starting

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