Abstract: A clip-type tensioner member having a piston in a housing and a ratchet mechanism. A plurality of rack teeth are formed on the outer periphery of the pistons. A clip member elastically engages with the rack teeth and is positioned in a recess in the housing. The points of contact of the clip member on the housing are different in the retracted and engaged positions.

Abstract: The present invention is directed to decrease the impact sound of the ratchet mechanism generated at the time of piston retraction. The tensioner includes a piston 3 slidable in the piston bore 2a of the housing 2 and an expandable circlip member 5 engageable with the engagement groove 3a of the piston 3. The piston bore 2a has a guide groove 20 formed therein that has front and rear stop surfaces 20a, 20b adapted to contact the circlip member 5. The engagement groove 3a is formed by a round seat portion S0 that the circlip member 5 is adapted to seat, a piston-retraction restricting portion S0S1 that is formed on the front side of the round scat portion S0 and a piston-advance permitting portion S0S2 that is formed on the front side of the round seat portion S0.

Abstract: The present invention is directed to decrease the impact sound of the ratchet mechanism generated at the time of piston retraction. The tensioner includes a piston 3 slidable in the piston bore 2a of the housing 2 and an expandable circlip member 5 engageable with the engagement groove 3a of the piston 3. The piston bore 2a has a guide groove 20 formed therein that has front and rear stop surfaces 20a, 20b adapted to contact the circlip member 5. The engagement groove 3a is formed by a round seat portion S0 that the circlip member 5 is adapted to seat, a piston-retraction restricting portion S0S1 that is formed on front side of the round scat portion S0 and a piston-advance permitting portion S0S2 that is formed on the front side of the round seat portion S0.

Abstract: The present invention provides a link plate for a silent chain that can introduce and maintain adequate lubricant in the pin aperture without decreasing the strength of the link plate. A silent chain (1) is comprised of a plurality of link plates (2) each having a pair of teeth (22) and pin apertures (21). The link plates (2) are interlaced in the lateral and longitudinal direction and pivotably interconnected to each other via connecting pins (3) inserted into the apertures (21). At least one groove (25) is formed at only the tooth (22) region on at least either one of an outer surface or an inner surface of the link plate (2). The groove (25) extends from the tip (22A) of the tooth (22) to the pin aperture (21). A width of the groove (25) becomes gradually wide toward the tip (22A) of the tooth (22) from the pin aperture (21).

Abstract: A hydraulic tensioner comprising a piston slidably inserted in a piston bore of a housing having rack teeth on an outer circumference thereof, a piston spring biasing the piston in a protruding direction, a pawl member having teeth engageable with the rack teeth of the piston to permit protruding movement of the piston but to block reverse movement of the piston provided in a pawl hole of the housing, and a pawl spring in a pawl spring hole of a generally elliptical cross-section that biases the pawl member in an engaging direction of the teeth of the pawl member with the rack teeth of the piston. A long axis of the generally elliptical cross-sectional shape of the pawl spring is oriented toward an axial direction of the piston. Wire portions of the pawl spring substantially follow the long axis that contacts an upper surface of the pawl member.

Abstract: A silent chain that can reduce friction loss during travel of a chain. A silent chain 1 is configured by stacking a large number of link plates 2 comprising a pair of tooth parts 22 and pin holes 21 in the thickness direction and the lengthwise direction, and also arranging guide plates 4 on the outermost side of the link plates 2, and coupling the link plates 2 and the guide plates 4 by means of connecting pins 3. Protruding parts 45 which can come into sliding contact with guide parts 56B of a chain guide 56 and guide parts 57B of a tension arm 57 during travel of the silent chain 1 are provided on an outer side surface 4A of the guide plates 4. The contact between the silent chain 1 and the chain guide 56 and tension arm 57 is made to be point contact, and friction loss during travel of the chain can be reduced.

Abstract: The present invention is directed to varying the oil pressure in the chamber of a hydraulic tensioner at multi-stages and to preventing an increase of the chain friction at various driving conditions. A hydraulic tensioner (1) includes a housing (2) that has a plunger bore (2a) to slidably receive the plunger (3) and a spool bore (2b) to slidably receive the spool (4). The housing (2) further has an inner relief aperture (22) to provide a connection between the plunger bore (2a) and the spool bore (2b) and outside relief apertures (23a, 23b) to provide a connection between the spool bore (2b) and the outside of the housing (2). The entire opening areas of the inside and outside relief apertures (22, 23a, 23b) that provide a connection between the plunger bore (2a) and the outside of the housing (2) through the spool bore (2b) are adapted to vary at least at two stages in accordance with the travel of the spool (4).

Abstract: The present invention is directed to decreasing noise from the onset of engagement with the sprocket teeth till seating thereon and also to reducing wear to the silent chain and the sprocket. A face (a) of a sprocket tooth, which contacts the chain at the onset of engagement, has a tooth profile that is an envelope (1) of trajectories described by the inner flank surface (23) of the link plate (2) when the chain moves linearly toward the sprocket (S) and engages with the sprocket (S) without causing a chordal action. A crest (b) of the sprocket tooth, which contacts the chain (S) at the time of seating on the sprocket tooth, has a tooth profile that is an envelope (m) of trajectories described by the crotch (25) of the link plate (2) when the link plate (2) rotates around the connecting pin during the wrapping motion of the chain around the sprocket (S).

Abstract: A power transmission chain includes a plurality of links and a bending-restraining mechanism. The bending-restraining mechanism includes a wire extending in a lengthwise direction along the chain and engaging at least three adjacent joints of the chain. The wire is formed such that it elastically deforms when an inside link rotates around the inner joint in a first direction from a linearly extending state, the wire thereby applying a bending resistance to the inside link during articulation of the chain. In one embodiment, the wire includes at least one curved section clipped around at least a majority of a circumference of at least one joint. In another embodiment, the wire is formed such that a predetermined bias due to a bending deformation of the wire is applied to the inside link when the chain is extended linearly.

Abstract: A tensioner that includes a piston supported slidably in a piston bore formed in a housing, a piston spring biasing the piston in the protruding direction, and a circlip member having an expandable ring-shaped body that is engageable with the rack teeth of the piston. In the piston bore, the ring-shaped body of the circlip member is adapted to engage with an upper and lower stop surface. The rack teeth of the piston are formed in such a shape that when the ring-shaped body of the circlip member engages with the upper stop surface of the piston bore, the piston is permitted to move in the protruding direction and, when the ring-shaped body of the circlip member engages with the lower stop surface of the piston bore, the piston restricts movement in the retracting direction.

Abstract: A silent chain includes a plurality of inside links each having a pair of teeth and pin apertures and connected to each other by connecting pins inserted into the pin apertures. At least three adjacent connecting pins have a wire extending substantially along the length of a chain. The wire is engaged with the connecting pins in such a way that bending resistance due to elastic deformation of the wire is applied to the chain during articulation of the chain.

Abstract: A sprocket more firmly fitted to the sprocket attachment surface of a shaft comprising a plurality of teeth formed around the outer periphery and a boss portion having a central through hole. Hard abrasive grains are adhered by the electro-deposition process to an end surface of the boss portion that contacts the sprocket attachment surface of the sprocket. When fastening the sprocket to the sprocket attachment surface of the shaft, the abrasive grains on the end surface easily plastically deform the sprocket attachment surface, forming irregularities on the sprocket attachment surface. Thereby, engagement of the end surface of the sprocket with the sprocket attachment surface of the shaft is strengthened. As a result, even a small-sized sprocket may be further firmly fitted to the sprocket attachment surface of the shaft.

Abstract: A blade-type tensioner 1 for imparting tension to a chain includes a blade shoe 2 with a chain sliding surface 20 that extends between the proximal end portion 21 and the distal end portion 22 of the blade shoe 2. The blade-type tensioner 1 further includes a blade spring 3 disposed opposite the chain sliding surface 20 of the blade shoe 2, and a bracket 5 that has a fixed pin 50 inserted into the pin aperture 21c of the proximal end portion 21 of the blade shoe 2 and that has a slide face 52 to slidably support the distal end portion 22 of the blade shoe 2. The proximal end portion 21 of the blade shoe 2 has a bulge portion 21d that bulges out toward the distal end portion 22 of the blade shoe 2.

Abstract: The present invention is a method and apparatus for controlling driving of the electric oil pump. The method includes the steps of deciding whether a predetermined time has elapsed after oil supply to the hydraulic chain tensioner has stopped, deciding whether an engine start prediction signal is inputted to a controller, and driving the electric oil pump to supply oil to the hydraulic tensioner when the engine start prediction signal is inputted. The present invention insures that oil pressure is maintained in the chamber of the hydraulic tensioner before cranking of the engine, thereby preventing oscillation of the chain and tensioner piston at the time of engine start up.

Abstract: A tensioner that includes a piston supported slidably in a piston bore formed in a housing, a piston spring biasing the piston in the protruding direction, and a circlip member having an expandable ring-shaped body that is engageable with the rack teeth of the piston. In the piston bore, the ring-shaped body of the circlip member is adapted to engage with an upper and lower stop surface. The rack teeth of the piston are formed in such a shape that when the ring-shaped body of the circlip member engages with the upper stop surface of the piston bore, the piston is permitted to move in the protruding direction and, when the ring-shaped body of the circlip member engages with the lower stop surface of the piston bore, the piston restricts movement in the retracting direction.

Abstract: A sprocket for preventing the partial wear on the teeth of the sprocket. The teeth of the sprocket comprised of a pair of side portions located on opposite sides of a tooth and a central portion located between the pair of sides. The pair of side portions has a hardness greater than the central portion.

Abstract: A link plate for silent chains includes a pair of teeth, each formed of an inside flank and an outside flank and a pair of pin apertures. A moment of force around a pin M=F×Lo, where F is a force applied by a sprocket tooth against the outside flank, and Lo is a length of a perpendicular drawn from a center O of a pin aperture to an action line of the force, is decreased by decreasing Lo. The link plate engages a sprocket tooth on an intersection between a straight line n and a flank, line n and the direction of a central line connecting each O forming a pressure angle ?, and contacting a circle having a center O and a radius r<0.25×P, where P is a pin aperture pitch. Also, ? of the outside flank satisfies an inequality, 32°??<34°, to lessen the force.

Abstract: A chain guide improves bending rigidity while satisfying requirements for compactness and weight reduction of an engine and restricting cost increases. The chain guide includes a guide body having an engaging protrusion capable of engaging with a long engaging hole formed in an engine block in a longitudinally slidable manner and a shoe fixed over the guide body and having a chain sliding surface. In this case, an upward support of the engaging protrusion of the guide body in the engaging hole of the engine block results in an increase in the bending rigidity of the whole chain guide. Moreover, the engaging protrusion of the guide body is only inserted into the engaging hole of the engine block. This does not cause an increase in size and weight, and causes only a slight change of a mold, leading to less cost increases.

Abstract: The present invention provides a blade-type tensioner system for a chain that can easily improve spring properties. A blade-type tensioner includes a blade shoe and a blade spring positioned on the back side of chain sliding surface of the blade shoe so as to impart tension to a chain through the blade shoe. The blade shoe is pivotably supported around a shoulder bolt inserted into a proximal end portion of the blade shoe, and a distal end portion of the blade shoe is slidably supported on a supporting face provided in the engine. The distal end portion of the blade shoe contacts a flat, first supporting face at a point. When tension in the chain is increased, the distal end portion contacts a concave, second supporting face at a point which is continuous with the first supporting face.

Abstract: A blade tensioner includes a blade shoe with a chain sliding face bending in an arch-like shape and a blade spring, arranged on a side opposite to the chain sliding face of the blade shoe, that applies spring force to a chain through the blade shoe. The tensioner also includes a bracket with a pin rotatably supporting a proximal end section of the blade shoe and a sliding section made of resin slidably supporting an end of the blade spring on the distal end section of the blade shoe when the blade shoe is deformed. The distal end section of the blade shoe preferably includes a pair of guide sections vertically provided along both surfaces of a sliding section of the bracket.