Abstract: Steel materials for continuously variable transmissions sheaves, and methods for manufacturing a continuously variable transmission sheaves, are provided. In the disclosed steel materials for continuously variable transmission sheaves, the steel materials satisfy the following expressions: 13.9?Fn1?15.5, and 1.20?Fn2?4.35 (in which Fn1=7×Cr?6×Si+4×Mn; and Fn2=Al×N×104).

Abstract: Steel materials for continuously variable transmissions sheaves, and methods for manufacturing a continuously variable transmission sheaves, are provided. In the disclosed steel materials for continuously variable transmission sheaves, the steel materials satisfy the following expressions: 13.9?Fn1?15.5, and 1.20?Fn2?4.35 (in which Fn1=7×Cr?6×Si+4×Mn; and Fn2=Al×N×104).

Abstract: A vane oil pump includes a rotor including a plurality of slits, a housing having an inner circumferential cam surface such that a first pump unit and a second pump unit taking in and discharging oil in accordance with rotation of the rotor are separately disposed in a rotational direction of the rotor, a plurality of vanes respectively fitted in the slits of the rotor, and a pressure adjusting device configured to adjust a second discharge pressure of the second pump unit to a lower pressure than a first discharge pressure of the first pump unit. A back pressure groove is disposed on the housing and is provided to supply back pressure oil to a bottom portion of each slit.

Abstract: A continuously variable transmission includes: a first pulley having a first fixed sheave and a first movable sheave; a first cylinder forming a first oil chamber with the first movable sheave; a second pulley having a second fixed sheave and a second movable sheave; a second cylinder forming a second oil chamber with the second movable sheave; and a transmission belt wound around the first pulley and the second pulley. The first cylinder has a first member that is fixed to a first shaft and a second member that is joined to an outer peripheral portion of the first member. A bearing is interposed between an outer periphery of the first member and an inner periphery of a case. A thickness, in an axial direction, of a portion of the first member that is configured to directly abut against the first movable sheave is larger than a thickness of the second member.

Abstract: A torque detection device in a power transmission device including a speed change mechanism, the torque detection device detecting torque on a rotary shaft that rotates with a gear, the torque detection device including: a first encoder having a first detected portion and directly fixed to the rotary shaft so as to rotate with the rotary shaft; a second encoder having a second detected portion and directly fixed to the gear so that the second encoder rotates with the gear and that the second detected portion is located near the first detected portion; and a rotational displacement detection sensor that detects rotational displacements of the first detected portion and the second detected portion.

Abstract: A power transfer device includes a hydraulic clutch capable of coupling and decoupling a secondary shaft of a CVT and axles to and from each other. A secondary pulley of the CVT includes a movable sheave movably supported by the secondary shaft, and a secondary piston that rotates together with the secondary shaft and that constitutes a second hydraulic actuator together with the movable sheave. The secondary piston of the second hydraulic actuator is used to define an engagement oil chamber of the hydraulic clutch.

Abstract: A power transfer device includes a hydraulic clutch capable of coupling and decoupling a secondary shaft of a CVT and axles to and from each other. A secondary pulley of the CVT includes a movable sheave movably supported by the secondary shaft, and a secondary piston that rotates together with the secondary shaft and that constitutes a second hydraulic actuator together with the movable sheave. The secondary piston of the second hydraulic actuator is used to define an engagement oil chamber of the hydraulic clutch.

Abstract: A power transmission device includes a belt-type continuously variable transmission; a first fluid pressure cylinder; a second fluid pressure cylinder; a pressure-adjustment and pressure-feed device; a fluid outflow/inflow device; and a control unit that controls the pressure-adjustment and pressure-feed device based on a fluid pressure that is obtained from a thrust that is required for the second pulley in accordance with a driving state and that, by controlling the pressure-adjustment and pressure-feed device in this manner, controls the fluid outflow/inflow device such that a gear ratio is varied within a permitted gear ratio range in accordance with the fluid pressure that is pressure-fed from the pressure-adjustment and pressure-feed device in conjunction with the pressure adjustment.

Abstract: A belt type continuously variable transmission includes a primary shaft and a secondary shaft, wherein the primary shaft is supported on a case via a first rolling element bearing, and the secondary shaft is supported on the case via a second rolling element bearing, the case is formed with a bolt hole at each of an even number of locations in a region separate from a shaft center plane, which is a plane that passes through a shaft center of the primary shaft and a shaft center of the secondary shaft, and first and second stopper plates that each hold down outer races of the first and second rolling element bearings are fixed to the case by bolts mounted in the bolt holes.

Abstract: A fixed sheave mounted on an input shaft and a movable sheave mounted on a cylindrical member that is slidably supported in the axial direction relative to the input shaft are respectively structured using annular members having the same shape. With this structure, the fixed sheave and the movable sheave can be common structural components, thereby enabling the structural components to be easily formed by making the shape thereof relatively simple. As a result, productivity can be further improved.

Abstract: A method of manufacturing a sheave member for a belt-type continuously variable transmission includes a forming step wherein an intermediate product having a sheave surface is formed by forging a steel material; a carburization step wherein the intermediate product is heated in a carburization gas; a gradual cooling step wherein the cooling speed is equal to or less than 20° C./sec, at least until the temperature of the intermediate product has passed through the transformation point; a high-frequency electrical heating step wherein a selected portion(s) of the intermediate product is heated; a water quenching step wherein the selected portion is quenched by contact with water; and a finishing step wherein a grinding process is applied to the intermediate product to attain the final shape. In the cooling step, preferably, the intermediate product is contacted with a cooling gas at a pressure lower than atmospheric pressure.

Abstract: A belt type continuously variable transmission includes a primary shaft and a secondary shaft, wherein the primary shaft is supported on a case via a first rolling element bearing, and the secondary shaft is supported on the case via a second rolling element bearing, the case is formed with a bolt hole at each of an even number of locations in a region separate from a shaft center plane, which is a plane that passes through a shaft center of the primary shaft and a shaft center of the secondary shaft, and first and second stopper plates that each hold down outer races of the first and second rolling element bearings are fixed to the case by bolts mounted in the bolt holes.

Abstract: A power transmission device includes a belt-type continuously variable transmission; a first fluid pressure cylinder; a second fluid pressure cylinder; a pressure-adjustment and pressure-feed device;a fluid outflow/inflow device; and a control unit that controls the pressure-adjustment and pressure-feed device based on a fluid pressure that is obtained from a thrust that is required for the second pulley in accordance with a driving state and that, by controlling the pressure-adjustment and pressure-feed device in this manner, controls the fluid outflow/inflow device such that a gear ratio is varied within a permitted gear ratio range in accordance with the fluid pressure that is pressure-fed from the pressure-adjustment and pressure-feed device in conjunction with the pressure adjustment.

Abstract: A fixed sheave mounted on an input shaft and a movable sheave mounted on a cylindrical member that is slidably supported in the axial direction relative to the input shaft are respectively structured using annular members having the same shape. With this structure, the fixed sheave and the movable sheave can be common structural components, thereby enabling the structural components to be easily formed by making the shape thereof relatively simple. As a result, productivity can be further improved.

Abstract: A method of manufacturing a sheave member for a belt-type continuously variable transmission includes a forming step wherein an intermediate product having a sheave surface is formed by forging a steel material; a carburization step wherein the intermediate product is heated in a carburization gas; a gradual cooling step wherein the cooling speed is equal to or less than 20° C./sec, at least until the temperature of the intermediate product has passed through the transformation point; a high-frequency electrical heating step wherein a selected portion(s) of the intermediate product is heated; a water quenching step wherein the selected portion is quenched by contact with water; and a finishing step wherein a grinding process is applied to the intermediate product to attain the final shape. In the cooling step, preferably, the intermediate product is contacted with a cooling gas at a pressure lower than atmospheric pressure.