Abstract: A hydraulic control circuit for an automatic transmission of a vehicle, the transmission including hydraulically operated coupling devices at least one of which is selectively operated to establish a corresponding one of speed steps, the hydraulic control circuit including electromagnetic valve devices which output respective hydraulic pressures to operate the hydraulically operated coupling devices, respectively, an all-fail detecting and switching valve device which is switched, based on an all-fail state of the electromagnetic valve devices in which none of the electromagnetic valve devices output the respective hydraulic pressures, to an operation state corresponding to a fail position to output, as a first hydraulic pressure, a source hydraulic pressure to a first hydraulically operated coupling device out of the plurality of hydraulically operated coupling devices, and an operation-state memory valve which is switched, based on a state of the vehicle before the all-fail state occurs, from a non-running

Abstract: A piston for an automatic transmission includes: (a) a cylindrical wall portion provided by a first piston member; (b) a bottom wall portion provided by a second piston member; and (c) an engaging portion at which the first and second piston members are engaged with each other such that the first piston member is movable relative to the second piston member in an axial direction of the piston by a small distance. The piston is characterized by further including (d) an elastic structure which is provided at the engaging portion, and which biases the first piston member in the axial direction, so as to restrain movement of the first piston member relative to the second piston member in the axial direction.

Abstract: A clutch device for an automatic transmission, including a clutch drum supporting frictional coupling elements, a clutch piston disposed radially outwardly of the clutch drum, and a rotary speed sensor disposed radially outwardly of the clutch piston to detect a rotating speed of the clutch piston. The clutch piston has an inner spline for engagement with an outer spline of the clutch drum to prevent relative rotation between the clutch piston and the clutch drum, and further has a plurality of recesses formed in an outer circumferential surface thereof and corresponding to respective teeth of the inner spline, and a plurality of oil holes formed therethrough at an axial position of the clutch device at which the rotary speed sensor is located. The recesses and the oil holes are equally spaced apart from each other in a circumferential direction of the clutch piston, and cooperate to provide a sensed portion to be sensed by the rotary speed sensor.

Abstract: A vehicular automatic transmission including a first planetary gear device and a first set of frictional coupling elements, which can be supported by a pump housing via first and second retainer rings, at predetermined axial positions within the pump housing, during assembling of the automatic transmission. The first retainer ring is fixed to a radially inner spline-fitting part of a cylindrical extending portion of the pump housing, while the second retainer ring is fitted in a first circumferential groove formed in a ring gear of the first planetary gear device and a second circumferential groove formed in the inner circumferential surface of a splined cylindrical portion of a first hub splined to the outer circumferential surface of the ring gear and the radially inner portions of the first set of frictional coupling elements. The automatic transmission is manufactured by assembling a subassembly with respect to a stationary cylindrical housing to which the pump housing is fixed.

Abstract: A piston for an automatic transmission, including a first piston member forming a cylindrical portion and a second piston member forming a bottom portion, wherein the first piston member has a plurality of engaging grooves formed in one of opposite axial end portions thereof, each of the engaging grooves having a radial surface extending in a radial direction of the first piston member, and the second piston member has a plurality of elongate claws (70) extending in a circumferential direction thereof and respectively corresponding to the engaging grooves, each elongate claw having a free end portion and a fixed end portion, and being bent in an axial direction of the second piston member such that the free end portion is spaced from the fixed end portion in the axial direction toward an open end of the piston, each elongate claw having a first engaging lug which is formed at the free end portion and which is held in engagement with the corresponding engaging groove and in pressing contact with the radial end

Abstract: A drive unit qualified as an automatic transmission- includes a rotational shaft transmitting power, a planetary gear mechanism linked to the rotational shaft, and a friction engagement device provided at the outer circumferential side of the planetary gear mechanism. The planetary gear mechanism includes a pinion gear, and a pinion shaft supporting the pinion gear in a rotatable manner. The pinion shaft includes an oil inlet through which oil flows in, an oil outlet provided so as to supply oil flowing in from the oil inlet to the friction engagement device, and an oil channel communicating the oil inlet with the oil outlet.

Abstract: A parking lock mechanism of an automatic transmission includes a parking gear provided in a casing, a parking pawl engaged with the parking gear to achieve a parking lock state, a parking rod moving in an axial direction to press the parking pawl against the parking gear, and a guide portion guiding movement of the parking rod in the axial direction. The guide portion is formed with a casing.

Abstract: A parking lock mechanism of an automatic transmission includes a casing, a parking gear provided in the casing, a parking pawl engaged with the parking gear to achieve a parking lock state, and a “parking pawl holding portion” suppressing inclination of the parking pawl in an out-of-plane direction (a direction shown with an arrow DR40). A groove portion is formed in the casing. A protruding portion is provided in a sleeve fixed to the casing. A side surface of the groove portion implements a “first portion” of the “parking pawl holding portion.” A base and protruding portion are formed from a member separate from the casing, and implement a “second portion” of the “parking pawl holding portion.

Abstract: A hydraulic control apparatus for an automatic transmission includes a first SL linear solenoid, a second SL linear solenoid, a third SL linear solenoid, and a fourth SL linear solenoid, which are normal closed type, and a sequence valve. The sequence valve connects the first SL linear solenoid to a servo of a C1 clutch, the second SL linear solenoid to a servo of a C2 clutch, and the fourth SL linear solenoid to a servo of a B3 brake at normal time. The sequence valve selectively connects a D range oil passage to the servo of the C1 clutch and the servo of the C2 clutch, and connects the D range oil passage to the servo of the B3 brake, when an electric failure gas occurred.

Abstract: A hydraulic control circuit for an automatic transmission of a vehicle, the transmission including hydraulically operated coupling devices at least one of which is selectively operated to establish a corresponding one of speed steps, the hydraulic control circuit including electromagnetic valve devices which output respective hydraulic pressures to operate the hydraulically operated coupling devices, respectively, an all-fail detecting and switching valve device which is switched, based on an all-fail state of the electromagnetic valve devices in which none of the electromagnetic valve devices output the respective hydraulic pressures, to an operation state corresponding to a fail position to output, as a first hydraulic pressure, a source hydraulic pressure to a first hydraulically operated coupling device out of the plurality of hydraulically operated coupling devices, and an operation-state memory valve which is switched, based on a state of the vehicle before the all-fail state occurs, from a non-running

Abstract: A hydraulic control apparatus of a vehicular automatic transmission has a plurality of hydraulic friction engagement devices that are selectively engaged and released to establish a plurality of forward speed change stages of different speed change ratios. The forward speed change stages are achieved through engagement of predetermined friction engagement devices, of the plurality of friction engagement devices. If it is determined that a predetermined speed change stage corresponding to a predetermined shift output is not established, the hydraulic control apparatus identifies a hydraulic friction engagement device having a bad engagement that is a cause of the non-establishment of the predetermined speed change stage, on the basis of the state of engagement oil pressure of the predetermined friction engagement device.

Abstract: A hydraulic control circuit for an automatic transmission of a vehicle, the transmission including hydraulically operated coupling devices at least one of which is selectively operated to establish a corresponding one of speed steps, the hydraulic control circuit including electromagnetic valve devices which output respective hydraulic pressures to operate the hydraulically operated coupling devices, respectively, an all-fail detecting and switching valve device which is switched, based on an all-fail state of the electromagnetic valve devices in which none of the electromagnetic valve devices output the respective hydraulic pressures, to an operation state corresponding to a fail position to output, as a first hydraulic pressure, a source hydraulic pressure to a first hydraulically operated coupling device out of the plurality of hydraulically operated coupling devices, and an operation-state memory valve which is switched, based on a state of the vehicle before the all-fail state occurs, from a non-running

Abstract: A method of manufacturing a powertrain member capable of suppressing an effect of heat distortion is provided. A method of manufacturing a powertrain member including a disk portion provided to extend from a boss portion in a direction perpendicular to a rotation axis and having a through hole formed in the disk portion includes the first through hole formation step of forming a tip hole which is at least a portion of the through hole, the chamfering step of chamfering at least a portion of the tip hole, the heat treatment step of performing heat treatment after chamfering, and the second through hole formation step of forming a desired shape of the through hole by laser processing after heat treatment.

Abstract: An automatic transmission includes a parallel-axis gear pair including a first gear having a shaft portion and a gear portion, and a second gear which meshes with the first gear; a case that has a supporting wall which is adjacent to the gear portion of the first gear and rotatably supports the shaft portion of the first gear; and a frictional engagement apparatus that includes friction members, a piston that presses on, so as to apply, the friction members, and a hydraulic chamber that holds hydraulic fluid which moves the piston in the direction of the friction members. As a result, both the shaft to shaft dimension as well as the axial dimension of the automatic transmission can be reduced.

Abstract: A piston for an automatic transmission, wherein a first piston member forming a cylindrical portion of the piston has a plurality of axial cutouts and a circumferential groove formed in one axial end portion thereof, and a second piston member forming a bottom portion of the piston has a plurality of radially extending engaging jaws fitted in the plurality of axial cutouts, while a retainer ring is fitted in the circumferential groove and held in abutting contact with the engaging jaws fitted in the axial cutouts, whereby the first and second piston members are fixed to each other. At least one of the engaging jaws of the second piston member cooperates with the retainer ring to form a gap therebetween, which prevents a stress concentration on portions of the circumferential groove adjacent to the axial cutouts, upon an axial movement of the piston, so that the required thickness of the retainer ring can be reduced, leading to size reduction of the piston.

Abstract: A development device includes a developer bearing member including a plurality of magnetic poles for bearing a two component developer, and rotating so that the toner is supplied to a latent image bearing member, a supply and conveyance path including a member configured to convey the developer in a first direction, a regulation member configured to regulate the developer on the developer bearing member, a collection and conveyance path including a member configured to convey the developer in a second direction parallel to the first direction, arranged below the development bearing member and at a substantially same height as the supply and conveyance path, an agitation and conveyance path including a member configured to convey the developer in a third direction opposite to the first direction, arranged at a substantially same height as the collection and conveyance path, and partition members partitioning the three paths.

Abstract: A cylinder tube of a second hydraulic cylinder is provided separate from a first piston of a first hydraulic cylinder and integrally fixed to an input shaft. Friction members of a first clutch and friction members of a second clutch are prevented from moving in a first direction by a snap ring attached to a connecting drum. The friction members of the first clutch are friction engaged by the first piston and the friction members of the second clutch are friction engaged by a second piston.

Abstract: A hydraulic control apparatus for switching an operation of a hydraulically operated mechanical apparatus, by selectively operating two frictional engagement elements of a first, a second, a third, and a fifth frictional engagement elements, the hydraulic control apparatus including a first control valve which, in association with an event that respective hydraulic pressures to operate the first and second frictional engagement elements are both produced, drains one of the third and fifth frictional engagement elements and outputs a control hydraulic pressure; and a second control valve which, when at least two hydraulic pressures of (a) the control hydraulic pressure and (b) respective hydraulic pressures to operate the third and fifth frictional engagement elements are supplied to the second control valve, drains the other of the third and fifth frictional engagement elements.

Abstract: There is provided a hydraulic pressure control apparatus for a vehicular hydraulic power transmission device with a lock-up clutch, in which an increase in the temperature of hydraulic oil in an engagement side oil chamber is suppressed, durability of frictional material is improved, and the lock-up clutch is appropriately controlled. A switching control valve (a lock-up relay valve 250 and a lock-up control valve 252) switches between connection and disconnection between each of two oil passages that communicate with an engagement side oil chamber 31, and each of a high pressure oil passage and a low pressure oil passage, according to the operating state of the lock-up clutch 11. For example, when the lock-up clutch is completely engaged, the hydraulic oil is supplied to both the two oil passages from the high pressure oil passage, hydraulic pressure PON in the engagement side oil chamber 31 is increased, and a sufficient transmission torque capacity of the lock-up clutch 11 is obtained.

Abstract: A piston for an automatic transmission, including a first piston member forming a cylindrical portion and a second piston member forming a bottom portion, wherein the first piston member has a plurality of engaging grooves formed in one of opposite axial end portions thereof, each of the engaging grooves having a radial surface extending in a radial direction of the first piston member, and the second piston member has a plurality of elongate claws (70) extending in a circumferential direction thereof and respectively corresponding to the engaging grooves, each elongate claw having a free end portion and a fixed end portion, and being bent in an axial direction of the second piston member such that the free end portion is spaced from the fixed end portion in the axial direction toward an open end of the piston, each elongate claw having a first engaging lug which is formed at the free end portion and which is held in engagement with the corresponding engaging groove and in pressing contact with the radial end