Abstract: A work fixing device capable of stably fixing the work, without any biasing, in the longitudinal direction of the work, of the fastening force for fixing the work. The moving mechanism of clamps is constructed by comprising a scroll disc as working disc forming a circular hole in which to insert the work at the center and scroll guides in spiral shape the winding direction of which is opposite to each other from the center toward the outer circumference on the both side faces, a rotary drive mechanism for rotatably driving this scroll disc, and scroll pieces having a fitting portion to be engaged with the scroll guides of the scroll disc and disposed on both sides of the scroll disc in a way to correspond to a plurality of clamps respectively.

Abstract: The present invention provides a work fixing device capable of stably fixing the work, without any biasing, in the longitudinal direction of the work, of the fastening force for fixing the work. The moving mechanism 3 of clamps 2 is constructed by comprising a scroll disc 4 as working disc forming a circular hole 41 in which to insert the work W at the center and scroll guides 42a, 42b in spiral shape the winding direction of which is opposite to each other from the center toward the outer circumference on the both side faces, a rotary drive mechanism 5 for rotatably driving this scroll disc 4, and scroll pieces 6 having a fitting portion 61 to be engaged with the scroll guides 42a, 42b of the scroll disc 4 and disposed on both sides of the scroll disc 4 in a way to correspond to a plurality of clamps 2 respectively.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: The present invention provides an apparatus for estimating clutch temperature estimates clutch temperatures that closely follow actual clutch temperature without a temperature sensor and at low cost. The apparatus employs method for calculating energy applied to the driving clutch according to the detected rotational speed difference and estimated torque and method for estimating a clutch temperature variation based on the calculated energy and estimating a clutch temperature based on the estimated clutch temperature variation.

Abstract: A limiter plug and a drain plug are juxtaposed in a valve block. The limiter plug is provided with a thermo-switch of which operation, when a predetermined temperature is reached, opens a communication passage for drainage by means of a limiter pin. The drain plug is provided with a drain pin for draining a high-pressure oil in conjunction with the drainage action of the limit pin induced by the thermo-switch so that, when the predetermined temperature is reached, it substantially nullifies the torque for switching from 4 wheel-drive to 2 wheel-drive. In the status of no operation of the thermo-switch, the drain pin when a predetermined torque is reached, gradually opens the drain hole while catching a balance, to limit the torque to a predetermined value.

Abstract: A valve block coupled to a rotor is provided with a drain mechanism that includes a drain pin adapted to open and close a drain hole. The drain pin is incorporated in a drain plug by providing a support by a return spring. The drain pin has an orifice for generating a flow resistance. One end turn portion of the return spring is press fitted into the interior of the drain pin having the orifice, while the other end turn portion of the return spring is press fitted into the interior of a limiter plug having a limiter pin, whereby the drain pin is rotationally positioned to alleviate cavitation noises.

Abstract: 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.

Abstract: 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.

Abstract: The manufacturing cost of a multi-stage pulley is reduced without coaxially arranging a plurality of groove forming sections. While a portion between groove sections 103 is being pushed by a pushing roller 204, the groove sections 103 are successively formed. While a portion of workpiece W2 pushed by a groove forming roller 206 to form one groove section 103a and a portion of workpiece W2 pushed by a groove forming roller 207 to form the other groove section 103b are being shifted from each other in the circumferential direction, one groove section (103a) and the other groove section (103b) are simultaneously formed. Due to the foregoing, when the groove sections 103 are formed, it is possible to prevent the deformation of the groove section 103 and the groove section 103 which is adjacent to it. Accordingly, it is possible to enhance the yield of the multi-stage pulley 100 without coaxially arranging a plurality of groove forming sections.

Abstract: 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.

Abstract: 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.

Abstract: 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≈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.

Abstract: 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.

Abstract: A rolling process for producing a spur gear. The process comprises the following steps: (a) bringing gear teeth of a generally wheel-shaped toothed tool into press contact with a peripheral portion of a generally wheel-shaped gear material at which portion gear teeth are to be formed; and (b) bringing gear teeth of a generally wheel-shaped backup roller into press contact with the peripheral portion of the gear material in course of formation of the gear teeth under rolling so that the gear teeth of the backup roller are to be in mesh with the gear teeth formed at the peripheral portion of the gear material under the action of the toothed tool. The backup roller has an inclined section for forming a chamfered portion of each tooth of the spur gear to be produced. The inclined section is located at a position corresponding to the chamfered portion of the spur gear.

Abstract: A toothed wheel is cold formed from a circular piece or plate of sheet metal by cold-forming an annular outer section of the sheet metal into a preform, while the sheet metal is held in a rotary holding unit and rotated about its preform axis. While the sheet metal is rotating, a thickening roller works against the sheet metal's an outer annular section to thicken the same and form a wheel having a generally uniform cross-sectional outer annular section and an integral central wall that extends radially inwardly from the outer annular section. The outer annular section is formed by a multi-stage cold rolling process, utilizing different thickening rollers. Then, while the preform is rotating, a curling roller works on the outer annular section to form an axially extending flange, forming a cylindrical or C-shaped wheel to form a final preform. Then, while the final preform is rotating, a tooth forming roller is meshed against the outer periphery of the flange.

Abstract: A synchronizer ring for performing synchronous sliding operation with and separating operation from a rotating object member, comprises a ring body having a sliding surface slidable in contact with the object member and a copper alloy flame-coated film formed on the sliding surface. The copper alloy flame-coated film has a Zn equivalent of 40 to 65, a surface porosity of 5 to 30 volume % and a thickness of 70 to 200 .mu.m. The copper alloy flame-coated film also may have a surface roughness (Rz) of 20 to 60 .mu.m, and a ceramic content of 5 to 30 weight %.

Abstract: A synchronizer ring for performing synchronous sliding operation with and separating operation from a rotating object member, comprises a ring body having a sliding surface in slidable contact with the object member and a molybdenum or molybdenum alloy flame-coated film formed on the sliding surface, the film having a ceramic present in an amount of 5 to 30 weight %. The flame-coated film may have a surface roughness (Rz) of 20 to 60 .mu.m. The flame-coated film may further have a surface porosity of 5 to 30%, preferably 7 to 25% and a film thickness of 70 to 200 .mu.m, preferably 90 to 120 .mu.m.