Other

Kazuhisa Shimada

Toshiharu Takasaki

Hirotaka Kusukawa

Shigeo Murata

Hiroyuki Nakano

Yoshiaki Tajima

Kiyonori Hirao

Masaki Nakamura

A torque varying mechanism comprises an accommodation hole that has a relief hole formed in its bottom and that receives a check ball therein. The accommodation hole is configured so as to present a relationship in which the area of flow passage between the accommodation hole and the check ball increases linearly as a function of the amount of displacement of the check ball after opening of the relief hole, after which the flow passage area keeps a unvarying value. A hysteresis characteristic is imposed on a switching point where switching is made between a high torque transmission characteristic and a low torque transmission characteristic relative to an increase and a decrease of the vehicle velocity.

Hydraulic power transmission joint

A joint includes therein a valve serving to cut off torque transmitted from a front wheel associated driving shaft to a rear wheel associated driven shaft by the action of a weight based on a centrifugal force when a predetermined number of rotations is reached. The valve is coupled to a rotor or a housing connected to the driven shaft so that the rotations of the valves are in synchronism with rotations of the driven shaft. For this reason, the number of rotations of the valve is determined by the number of rotations of the rear wheel associated with the driven shaft, allowing the torque to be cut off depending on the vehicle velocity.

A drain plug is disposed in a drain hole through which oil is discharged from a high-pressure chamber formed in a valve block. Within the drain plug there is arranged a drain pin that slidably opens and closes the drain hole. A fixed pin serves to restrict a displacement of the drain pin. A thermo-switch is located within a low-pressure chamber behind the drain pin in such a manner as to be urged by a return spring so that the drain pin is pressed to keep the drain hole closed. When a predetermined temperature is reached, the thermo-switch allows its head pin to extend, with the reaction force as a result of abutment of the head pin against the fixed pin causing the thermo-switch to retreat to release the pressing force exerted on the drain pin. In consequence, the drain pin is displaced by a high pressure toward the direction in which the drain hole is opened, allowing high-pressure oil to be drained into the low pressure side.

Drain mechanism for hydraulic power transmission joint

An axially extending extension is formed on a bearing retainer provided adjacent to a valve block of a joint and press-fitted into the interior of a housing. The extension has at its outer peripheral end a bearing by way of which the bearing retainer is rotatably supported by a differential gear case located outside thereof. This allows moment arising from rotational secondary torque received by the housing to be transmitted from the bearing retainer extension via the bearing to the outside differential gear case, thereby preventing the moment from acting on a main shaft which is a centrally located output shaft.

A torque characteristic shifting mechanism is provided in an accommodation hole of a rotary valve. The torque characteristic shifting mechanism changes over the torque characteristics in a multi-step manner with an increase of the vehicle velocity by setting the distances so as to meet the relationships R3&ap;R2>R1 or R2>R3>R1 where R1, R2 and R3 are the distance from a center of rotation of a weight member accommodated rockably around the center of rotation to a center of the ball blocking the drain hole, the distance from the center of rotation to a center of gravity of the weight member and the distance from the center of rotation to a center of a spring, respectively.

A plunger is accommodated in each of a plurality of plunger chambers formed axially in a rotor, with the plunger being displaced by rotation of a cam face associated with a housing. A first one way valve for intake is incorporated in the head of each plunger and a second one way valve for discharge is disposed within in a discharge hole leading to the plunger chambers. The intake stroke of the plunger caused by rotation of the cam opens the first one way valve to suck oil from a low pressure chamber into the plunger chamber. The discharge stroke of the plunger opens the second one way valve to allow the discharged oil to flow through the orifice into the low pressure chamber, whereby a torque corresponding to the relative rotational-speed difference is transmitted from the housing side to the rotor side.

Growing community of inventors

Shizuoka, Japan

Kazuhisa Shimada