Aisin Seiki Kabushiki Kaisha

Toyota Jidosha Kabushiki Kaisha

Yukimori Kobayashi

Yoshio Okabe

Eiji Shirai

Hisashi Kodama

Katsumi Hirabayashi

Masaharu Hayashi

Makoto Ishikawa

Toshio Takeda

Shinji Kazaoka

Tomiaki Atsumi

Tamotsu Kamiya

An automatic hydraulic tensioner according to the present invention is provided with a communication mechanism for allowing a space radially inside a plunger-side end wire portion of a coil spring to communicate with a small clearance between the plunger and a cylinder. This automatic hydraulic tensioner thus succeeds, with a simple structure, in preventing bubbles from remaining within a pressure chamber and appropriately maintaining the tension applied to a power transmitting means such as a belt, a chain or the like.

Automatic hydraulic tensioner

An auto-tensioner including a body having a cylindrical bore defined therein; a shaft having first and second ends, the first end of the shaft being slidably and rotatably engaged with the cylindrical bore of the body, the body including a mechanism for sealing the shaft in the cylindrical bore so as to be fluid-tight; a support arm having upper and lower ends, the lower end of the support arm being fixedly connected to the second end of the shaft; a pulley rotatably connected to the upper end of the support arm, the pulley being operatively engaged with a belt under tension; a mechanism for rotatively urging the shaft and the support arm whereby the support arm maintains a tension engagement between the pulley and the belt, the urging mechanism being operatively connected between the body and the shaft; and a mechanism for converting rotational movement of the shaft into axial movement thereof along the cylindrical bore, the converting mechanism operatively connected between the shaft and the body, wherein the cylindrical bore includes an inner end and an outer end, the inner end of the cylindrical bore being formed so as to define a pressure chamber and a fluid chamber between the inner end of the cylindrical bore and the first end of the shaft, the pressure and fluid chambers are further formed so as to define a narrow fluid passage therebetween, the pressure and fluid chambers are filled with a viscous fluid, the body has a reservoir chamber defined therein and formed so as to be located above the pressure and fluid chambers, the reservoir chamber is filled with viscous fluid and gas, a first main fluid passage is defined in the body to communicatively connect the pressure chamber with the reservoir chamber, and a second main fluid passage is defined in the body to communicatively connect the fluid chamber with the reservoir chamber; and a valve mechanism located in the first fluid passage for selectively controlling fluid communication of the pressure and fluid chambers with each other and with the reservoir chamber.

Auto-tensioner

A tensioner for vehicle belts produces reduced rattling because radial forces are not transferred to the plunger. A tensioner body has a columnar hole extending from an open end toward a closed end. The plunger is fitted into the columnar hole and separates the columnar hole into first and second chambers. The plunger has sufficient clearance with respect to the body to permit restricted passage of fluid between the chambers. A rod pressed by the belt extends into the columnar hole and presses the plunger against the biasing force of a spring. In order to reduce the transfer of radial forces from the rod to the plunger, either the lower surface of the rod or the upper surface of the plunger is formed in a semi-spherical shape.

Tensioner with reduced rattling

For preventing very small amplitude vibrations of the rod in a tensioner during high speed movement of a belt to be tensioned by the tensioner, a tube which is connected to a plunger which moves together with the rod is overlapped with a stationary member so as to define an annular clearance therebetween in an operating chamber of the tensioner. By filling an operating fluid in the clearance, shear strain is generated upon high speed movement of the plunger, which resists movement of the plunger.

Tensioner

A hermetically sealed autotensioner used for adjusting tension of engine belts comprises a cylinder, a plunger slidably fitted in the cylinder and having a rod projeced from the cylinder, a free piston slidably fitted in the cylinder, and a rod guide fitted in the tip portion of the cylinder so as to slidably support the rod. When a large thrust force acts on the rod, the rod guide serves as a bearing for the rod so that no scuffing or rocking motion occurs between the cylinder and the plunger.

Hermetically sealed autotensioner

For adjusting an angular phase difference between an engine crank shaft and an engine cam shaft, fluid under pressure is supplied into one or more chambers defined therebetween. The adjusted condition is maintained or held by mechanical engagement between both shafts.

Device for adjusting an angular phase difference between two elements

A self-contained type automatic belt tensioner adjusts a tension of an engine timing belt for automobiles. The tensioner comprises a body, a plunger slidably mounted in the body, a reservoir chamber located in the plunger, a pressure chamber disposed between the plunger and a closed wall of the body, a rod member fixed to the plunger, a bellows shaped elastic diaphragm located in the reservoir chamber with one end thereof being fixed to the rod member and the other end being fixed to the body, a check valve allowing a fluid flow only from the reservoir chamber to the pressure chamber, and a return spring interposed between the plunger and the closed wall of the body so as to bias said plunger in the direction of the rod member.

Self-contained type automatic belt tensioner

A free piston type auto-tensioner adjusts a tension of an engine timing belt for automobiles. The auto-tensioner includes a body, a plunger slidably disposed in the body to form a first oil chamber, a free piston slidably disposed in the body to form a second oil chamber, a first seal member disposed between the body and the piston, a second seal member disposed between the piston and a rod of the plunger, an oil passage formed in the plunger to establish an oil communication between the first and second oil chambers, a check valve disposed in the oil passage, a first spring biasing the plunger, and a second spring biasing the piston.

Free piston type auto-tensioner

A cylinder control device for a variable-cylindered engine. The device comprises a body slidable within a bore formed in a block and urged by a spring always in contact with a cam, a plunger mounted in the body and slidable by hydraulic pressure in the direction perpendicular to the direction of sliding of the body, the plunger having a groove which is adapted to be engaged by the upper end of a valve stem 40 and an escape bore which is adapted to be positioned right above the upper end of the valve stem when the plunger is slided to a cylinder-inoperative position; and means for controlling said application of the hydraulic pressure to the plunger under the control of a computer. When the computer provides an instruction for normal operation of the cylinder, the plunger is held at a position where the upper end of the valve stem engages with the groove in the plunger so that, when the cam is rotated, the valve stem is depressed through the body thereby to open the valve port, whereas, when the hydraulic pressure is applied to the plunger so as to urge the plunger to a valve-inoperative position, the upper end of the valve stem escapes into the escape bore in the plunger when the body is depressed by the cam, so that the valve stem is not depressed and the valve is kept closed, thereby keeping the cylinder inoperative.

Cylinder control device for variable-cylindered engine

A hydraulic valve lifter for a variable displacement engine includes a body member, a check valve disposed within the body member for controlling a pressure chamber and a reservoir chamber, a sleeve member secured to one end of the body member, a plunger member slidably disposed in an axial bore of the sleeve member, and a solenoid valve having a valve rod for actuating the check valve. The direction of movement of the check valve is disposed at right angles to the axial direction of the body member. The direction of movement of the valve rod is the same as the direction of the movement of the check valve.

Growing community of inventors

Gamagori, Japan

Yukimori Kobayashi