Yuji Kurematsu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
Abstract: To provide a sprocket that reduces the influence of tension fluctuations concurrent with load torque changes to suppress noise and vibration and that allows for a weight reduction while retaining high strength as well as enables high productivity, and a drive mechanism that uses this sprocket. Sprocket teeth are configured by providing a cushioning layer on tooth faces of tooth portions of a sprocket base body made of a high-rigidity material. The sprocket teeth include the cushioning layer that varies in thickness.
Abstract: To provide a tensioner capable of keeping oil pressure in an oil pressure chamber stable with a simple structure. The tensioner includes a pressure adjusting mechanism that adjusts oil pressure in the oil pressure chamber. The pressure adjusting mechanism includes a cylinder part, a piston unit set inside the cylinder part so as to be able to approach and separate from the oil pressure chamber, and a piston biasing unit. Between the cylinder part and the piston unit, a liquid tight condition is kept at any place between a position where the piston unit has moved closest to the oil pressure chamber and a position where the piston unit has moved closest to the adjustment space.
Abstract: To provide a simple-structured chain guide with improved durability and capable of preventing detachment or breakage of a supplementary member and of reliably reducing vibration and noise. The chain guide includes a supplementary member made of a different material from a guide body. The supplementary member is configured to have an engaging hole, which allows attachment of the supplementary member to a side face of a support wall part provided between a guide part and a base part of the guide body.
Abstract: Provided is a tensioner which can ensure, with a simple structure, both the stability of the installation state of a check valve and the capacity of an oil storage chamber. A tensioner has a plunger, a housing, a check valve, and a coil spring. The plunger has a front-side plunger part having a pressing front end portion, and a rear-side plunger part disposed on the rear side of the front-side plunger part and having a valve movement restricting portion. The check valve is disposed on the rear side of the valve movement restricting portion. The coil spring is disposed so that one end thereof is in contact with a housing bottom portion and the other end thereof is in contact with the rear side of the check valve.
Abstract: A tensioner with a simple structure is provided, which is capable of keeping oil pressure in a first high oil-pressure chamber stable and holding a chain favorably. The tensioner includes a plunger, a housing, a check valve, an inner sleeve, and a biasing member. In the housing, a second high oil-pressure chamber and a unit setting part are formed. In the unit setting part, a relief valve unit is set. A gap between an inner circumferential surface of a plunger hole and an outer circumferential surface of the inner sleeve functions as part of an oil flow passage that connects the first high oil-pressure chamber and the second high oil-pressure chamber.
Abstract: To provide a simple-structured chain drive mechanism that can reduce the noise generated when the chain sits on the sprocket, prevent deterioration of power transmission efficiency, and retard the progress of wear on the sprocket or chain. The chain drive mechanism includes a sprocket having a plurality of teeth, and a chain having a plurality of link plates and configured to be put around the sprocket. The sprocket includes a pair of flanges protruding circumferentially around the sprocket such as to sandwich the plurality of teeth from sides. The chain includes a pair of seat portions on both sides of the chain so that the flanges abut on the seat portions from a circumferential direction of the sprocket when the chain sits.
Abstract: To provide a sprocket that reduces the influence of tension fluctuations concurrent with load torque variations to suppress noise and vibration, and that prevents an increase in tension fluctuations, noise, and vibration even when the chain tension is low and the load torque is small, and in regions where engagement between the chain and sprocket is free of the influence of tension. The sprocket has a plurality of seating points for the chain when the chain sits under no load set between adjacent pairs of the teeth such that their radial positions change in a circumferentially continuous manner. The radial positions of the seating points under no load have a variation pattern in which the radial positions increase and decrease depending on circumferential positions of the seating points.
Abstract: An object of the present invention is to provide a chain guide that eliminates the burden of assembling a guide shoe and a base member together, and prevents the guide shoe from being limited in its movement in the longitudinal guiding direction relative to the base member to improve durability. The guide shoe and the base member of the chain guide according to the invention are united by being integrally molded. The chain guide includes a fixed engaging part where the guide shoe engages with the base member such that the guide shoe is restricted from moving in the longitudinal guiding direction relative to the base member, and a movable engaging part where the guide shoe engages with the base member such that the guide shoe is slidable relative to the base member. A molding gate mark is positioned at or near the fixed engaging part.
Abstract: To provide a rotating member that allows formation of protrusions to be dug into an opposite surface with a simple configuration, and that can prevent a direction-dependent reduction of anti-slip effect and provide sufficient slip prevention in the direction of torque as well as in the radial direction, and a method of forming this rotating member. The rotating member has a boss and an anti-slip surface on at least one of both axial end faces of the boss. The anti-slip surface includes a plurality of crater-like depressions each having a peripheral protrusion. At least some of the plurality of crater-like depressions are arranged serially to form a plurality of crater chains.
Abstract: In a sprocket including a cushion ring coming into contact with link plates of a chain, the cushion ring includes, on an outer circumferential surface, a plurality of convex sections coming into contact with the link plates, and the plurality of convex sections are provided at corresponding positions to tooth tips at identical pitches to a plurality of teeth and include convex sections having different shapes.
Abstract: To provide a simple-structured tensioner that generates less knocking noise at the start-up of the engine and that prevents an excessive chain tension, severe friction, noise or vibration during the running of the engine, while also reducing production costs. The tensioner includes a ring control mechanism that controls the position of a resilient ring. The ring control mechanism includes a front-side restricting part having a front-side restricting surface and capable of restricting forward movement of the resilient ring, and a rear-side restriction member having a rear-side restricting surface and capable of restricting rearward movement of the resilient ring. The front-side restricting part is fixed to or formed integrally with the housing. The rear-side restriction member is disposed movable in a front to back direction relative to the housing and the plunger.
Abstract: An orifice member is disposed in a plunger including a plunger hole that forms a hydraulic chamber in conjunction with a plunger housing hole in a housing. The orifice member includes a deformed fitting section deformed to fit on the inner circumferential surface of the plunger hole, a communication section that causes a surface in contact with the top surface on the front side of the plunger hole and a surface on the hydraulic chamber side to communicate, and an orifice groove that communicates with the communication section and an external relief hole provided in the plunger on the surface in contact with the top surface on the front side of the plunger hole to constitute an orifice.
Abstract: To provide a sprocket that reduces the influence of tension fluctuations concurrent with load torque variations, that suppresses noise and vibration, and that prevents an increase in tension fluctuations, noise, and vibration even when the chain tension is low and the load torque is small, or in regions where a chain and the sprocket engage without being affected by the tension. The sprocket has a plurality of teeth mating with the chain that are provided with an equal pitch therebetween, and that include teeth with different working pressure angles relative to the chain.
Abstract: To provide a chain tensioner that enables a reduction in the number of parts to be machined, the number of assembling steps, and a reduction in the amount of oil flowing outside, without having to increase the size of the chain tensioner. An inner sleeve, which includes a check valve unit on the side of an oil pressure chamber and a pressure adjusting unit on the outer circumference thereof, is disposed inside a plunger. The inner sleeve includes a base part, a sliding cylindrical part, and a movement restricting part. The pressure adjusting unit includes an annular relief valve that is slidably fitted on the sliding cylindrical part and that makes sliding contact with an inner surface of the plunger, and a relief spring that biases the relief valve toward the movement restricting part. The sliding cylindrical part has a relief hole that communicates with the space inside.
Abstract: There is provided a chain guide that reduces a space occupied by the chain guide in an engine room while maintaining required strength, rigidity, and durability with a simple configuration, reduces the number of manufacturing steps and the waste of a material, does not require a structure that permits an error, prevents increases in vibration and noise during use, and reduces the burden of a maintenance operation. The chain guide has a guide shoe and a base member that reinforces the guide shoe, and an attachment portion includes an attachment member that is provided separately from the guide shoe and the base member and can be fixed to at least one of the guide shoe and the base member or both of the guide shoe and the base member.
Abstract: To provide a tensioner that has a simple structure and is easy to assemble, and is configured to smoothly relieve pressure during oil release with reduced flow resistance so that the oil pressure in an oil pressure chamber is kept stable in a favorable manner. A relief valve unit includes a cap member that fits with a seat member to retain a stopper member inside the seat member. An external relief hole, which causes a relief-side space in a plunger hole to communicate with the outside of a plunger, opens radially in an outer circumferential surface of the plunger.
Abstract: Provided is a sprocket which suppresses generation of order sounds corresponding to cycles and prevents increase in tension fluctuations, noise, and vibrations caused by resonance while alleviating the influence of the tension fluctuations corresponding to load torque fluctuations and suppressing noise and vibrations. A plurality of teeth formed to engage with a chain are arranged to form a phase fluctuation pattern of a waveform having a phase which fluctuates between positive and negative sides, and the phase fluctuation pattern is set to have parts having different wavelengths.
Abstract: To provide a tensioner and a relief valve unit that enable a reduction in the number of parts to be processed and the number of assembling steps, reduce the amount of oil flowing out to the outside, prevent damage to the check valve, and improve the oil recovery rate. The relief valve unit that releases oil when pressure inside an oil pressure chamber reaches or exceeds a predetermined high pressure includes a check valve unit that stops reverse flow of oil flowing into the oil pressure chamber as a valve element, the check valve unit being slidably inserted in the relief valve unit. The relief valve unit includes a unit pressing spring that presses the check valve unit toward a relief valve seat. The check valve unit includes an oil passage for allowing oil to flow between an inner side and an outer side of the check valve unit.
Abstract: To provide a chain tensioner that can maintain the pressure of the oil pressure chamber at a correct level to achieve a desired reaction force and damping characteristics corresponding to the rpm, and enable a reduction in the number of parts to be machined and the number of assembling steps; reduce the amount of oil flowing out of the system; and prevent damage to the check valve, without causing an increase in size of the chain tensioner. The chain tensioner includes a check valve unit 150 that stops reverse flow of oil flowing into an oil pressure chamber 101, and a first relief valve unit 160 and a second relief valve unit 170 that release oil when the pressure reaches or exceeds a predetermined high level. The second relief valve unit 170 has a higher valve opening pressure than that of the first relief valve unit 160.
Abstract: Provided is a tensioner with which efficiency of recirculation of oil can be improved and dependency on oil supplied from an oil pump or the like can be reduced. The tensioner includes a pressure adjustment mechanism, wherein the pressure adjustment mechanism includes a cylinder portion and a piston that is disposed in the cylinder portion so as to be capable of moving in a front-rear direction and that divides an interior space into an oil storage chamber and an adjustment space, and a liquid-tight state is maintained between the cylinder portion and the piston in all positions between a position of the piston where the piston has moved closest to the oil storage chamber side and a position of the piston where the piston has moved closest to the adjustment space side.