Tsubakimoto Chain Company

Honda Motor Co., Ltd.

Yoshio Kurokawa

Tsutomu Namie

Hiroshi Hashimoto

Nobuyuki Fujimoto

Toyonaga Saitoh

Tatsuya Konishi

Kazuyuki Iwata

Kaori Mori

Katsuya Nakakubo

Toyoakira Fukui

Shigenobu Sugasawa

Yutaka Minami

Timothy Marx

In a hydraulic tensioner having a relief valve inside its plunger, a relief valve spring-receiving plug, press-fit into the plunger is formed by forging a plurality of flat surfaces on its exterior. These flat surfaces, in cooperation with the cylindrical inner wall of the plunger, form plural oil passages, each having a segment-shaped cross-section. The oil passages allow flow of oil past the plug to a discharge opening at the front end of the plunger, and the flow of oil is substantially unaffected by circumferential displacement of the oil passages on the periphery of the plug relative to the oil passages on the periphery of the relief valve seat.

Hydraulic tensioner with improved relief valve

In a ratchet type chain tensioner, having a toothed rack on its plunger and a pawl cooperable with the rack, a recess is provided between the front end of the rack and the protruding end of the plunger. In the initial stages of operation of the tensioner, the pawl can enter the recess while permitting the plunger to protrude and retract freely within a limited range. Thereafter, when the chain controlled by the tensioner becomes elongated, the pawl cooperates with the rack to limit retraction of the plunger.

Ratchet type tensioner

A plunger stop for temporarily holding the plunger of a ratchet type chain tensioner in place during installation of the tensioner, or during mounting or removal of the chain, comprises a bifurcated part inserted into a groove in which a pivoted ratchet pawl is situated. The bifurcated part is sandwiched between the pivoted ratchet pawl and a part of the tensioner housing, with the bifurcated part straddling a ratchet pawl-biasing spring in the groove. A grip, which is integral with the bifurcated part protrudes outside the tensioner housing so that it can be grasped manually for removal.

Ratchet tensioner having plunger stop

In a ratchet-type hydraulic tensioner for use with a timing chain of an internal combustion engine, two or more oil reservoirs gradually receive oil fed under pressure from an external source, and supply the oil through a hydraulic valve mechanism to a high pressure oil chamber formed by a plunger and a housing in which the plunger is slidable. Throttle holes, formed in partition walls separating the reservoirs, control the flow of oil from one reservoir to another. An excess oil discharge hole is optionally provided in one of the reservoirs. The invention prevents abnormal protrusion of the plunger, reduces chain noise and component damage due to wear, and rapidly re-establishes proper tension on engine start-up.

Ratchet-type hydraulic tensioner

In a hydraulic tensioner having a relief valve mechanism in which a spring-biased valve element is reciprocable in a bore, hitting sounds produced by collision of the relief valve element with a plug in the bore, and wear and breakage of the biasing spring, are prevented by providing an oil relief hole in a peripheral wall of the relief valve bore at a position where it is closed by the relief valve element when he relief valve element is moved by a rapid increase in oil pressure.

Hydraulic tensioner with relief valve mechanism

A plunger equipped with a relief valve mechanism is slidably mounted in a tensioner housing. The relief valve mechanism has a valve spring disposed between a valve and a spring retainer plug in a compressed condition. The spring retainer plug has a stopper surface formed on the side which opposes the valve. The maximum displacement of the valve and the maximum amount of compression of the valve spring are defined by the stopper surface so that the maximum shear stress acting in a wire of the valve spring is less than a fatigue limit of the valve spring wire.

Tensioner with relief valve mechanism

The frictional type connector 10 includes an inner ring 20, an outer ring 30, and bolts 40. The outer surface of the inner ring 20 is formed into a tapered surface 23 which decreases the diameter from a flange portion 21 toward the other end of the inner ring. The outer ring 30 has an inner tapered surface 31, so that the tapered surface can face the outer tapered surface 23 of the inner ring 20. The taper angle .theta.i of the tapered surface of the inner ring 20 is larger than the taper angle .theta.o of the tapered surface of the outer ring 30.

Growing community of inventors

Osaka, Japan

Yoshio Kurokawa