Abstract: The temperature of the oil (hydraulic fluid) which is used to engage the friction elements of the transmission is sensed. When the temperature exceeds a predetermined level, the level of line pressure which is used during shifting (lower than that used during non-shifting operations) is increased to compensate for the loss in viscosity and lubricative properties of the oil.

Abstract: A supporting structure for control elements of an automatic transmission including a multiple-disc clutch having a piston operated by hydraulic pressure from a control valve unit and a cylinder slidably supporting the piston, and a one-way clutch having outer and inner races and a series of sprags placed between both of the races so as to mechanically jam depending on the rotational direction of the outer race, comprises a support member comprised of the cylinder and the inner race which are integrally formed with each other, and a transmission case for fixing the support member on the inner surface thereof from the inside of the transmission case by means of bolts.

Abstract: A parking gear mounting structure for an automatic transmission includes an input shaft which is supported by a transmission case in such a manner as to be prevented from moving radially with respect to an axis of the input shaft, an output shaft which is arranged coaxially with the input shaft and is also supported by the transmission case in such a manner as to be prevented from moving radially with respect to an axis of the output shaft, and a planetary gearset provided between the input shaft and the output shaft. The planetary gearset has a pinion carrier which is provided with a parking gear in a fixed relationship thereto. The parking gear is engageable with a parking gear locking member for locking the parking gear when the transmission is in parking. The pinion carrier is mounted onto the output shaft to rotate as a unit with the output shaft. A connecting member is provided for transmitting driving power from the input shaft to the planetary gearset.

Abstract: During minimal load or so called power off upshifts, the level of the line pressure which is applied during the inertia phase of a friction element which becomes engaged as a result of the upshift, is controlled in accordance with the rotational speed difference between parts of the friction element which are rotatable relative to one another.

Abstract: An automatic power transmission includes a primary transmission unit having plurality of gear elements for establishing predetermined speed ratios and a subsidiary transmission unit having an under-drive gear element for establishing at least one and a direct drive. Each gear element is associated with a friction element which controls associated one of the gear element for establishing one of a plurality of predetermined speed ratios. The friction element is connected to a hydraulic circuit which controls position of the friction element between engaged position and released position for establishing the one of speed ratios.

Abstract: An output shaft is supported by means of a ball bearing at one end, a radial needle bearing and a thrust bearing. The ball bearing is arranged for supporting the output shaft against most part of radial load. On the other hand, the trust bearing is arranged for supporting the output shaft against the thrusting force which is exerted on the output shaft while the engine driving torque is transferred therethrough. Such construction reduces radial and thrusting stress to be exerted on the needle bearing. Therefore, the radial needle bearing to be used in the shown construction is required substantially small load capacity and thus can be satisfactorily small for allowing the transaxle unit to be designed compact.

Abstract: A downshift control in an automatic transmission is disclosed wherein magnitude of servo activating hydraulic fluid pressure is temporarily decreased as a function of vehicle speed when the automatic transmission effects a downshift from a current gear ratio to a new gear ratio. Owing to this arrangement, a fluid operated frictional device associated with the current gear ratio is released quickly without any lag to allow quick increase in engine speed during the downshift with the throttle fully opened at a high vehicle speed, i.e., a power-on downshift at high vehicle speed.

Abstract: An automatic power transmission includes a clutch drum integrally connected with an one-way clutch which is fixed to a support secured on a transmission casing so that each one bearing is required for supporting the clutch drum and the one-way clutch. A sun gear is also supported by means of a single bearing and is integrally formed with a spline which is loosely engageable with a spline of the clutch drum so that the radial force may not act in the spline engagement while an engine output torque is transmitted therethrough.

Abstract: A compact change speed transmission comprising two planetary gear sets which are selectively controlled by clutches and brakes to provide four forward speed ratios and a reverse speed ratio. There are a forward clutch, a forward one-way clutch, and a low one-way clutch which, when the forward clutch is engaged, provide a path of transmission of reaction to a stationary part thereby establishing a path of transmission of torque through at least a part of two planetary gear sets to establish a predetermined one forward speed ratio. A low and reverse brake and an overrun clutch are provided. When both of them are engaged, they hinder the action of the low one-way clutch and that of the forward one-way clutch thereby providing engine braking during running with the predetermined one forward speed ratio. For compact arrangement, the overrun clutch is disposed within a clutch drum of the forward clutch with its actuating piston slidably received by an actuating piston of the forward clutch.

Abstract: An accumulator is disposed in a space defined in the transaxle case adjacent two shafts and/or the intermeshing gears associated therewith. The bore of the accumulator is formed in a web or the like which reinforces the casing at the site where a bearing associated with one of the gears is disposed. The conduits which interconnect the accumulator with the valve body exhibit sufficient flow resistance to obviate the need for separate orifices.

Abstract: The automatic transmission case includes a hole for allowing a tool to be inserted when tapping a hole which receives an anchor pin for a band brake and to receive an electrical connector for wiring between the inside of the transmission case and the outside thereof.

Abstract: In order to ensure that an adequately high gear ratio (such as top gear) is engaged momentarily before the first gear ratio and thus reduce select shock when a manual selector valve is moved from neutral (N) to drive (D) while simultaneously enabling the provision of a flow restriction required to ensure smooth automatic upshifting, a valve which by-passes the flow restriction is provided. This by-pass valve includes a chamber provided with a drain port which is closed by a device (such as a solenoid valve) responsive to an engine associated with the transmission entering an idling condition.

Abstract: In order to securely lubricate a final drive unit of a transaxle including a torque converter and a hydraulically controlled transmission, the line pressure regulator valve of the hydraulic control system is arranged to discharge surplus hydraulic fluid via first and second drain ports into a conduit arrangement which fluidly communicates with both of the torque converter and the final drive unit. The conduit arrangement is arranged to relieve any excess fluid fed thereto from the first drain port toward the final drive unit in addition to that fed thereto from said second drain port.

Abstract: In order to ensure that an adequately high gear ratio (such as top gear) is engaged momentarily before the first gear ratio and thus reduce select shock when a manual selector valve is moved from neutral (N) to drive (D), while simultaneously enabling the provision of a flow restriction required to ensure smooth automatic upshifting into the high gear in question, a control valve is provided which, in response to the engine associated with the transmission being sensed in an idling condition and the manual selector valve being moved from (N) to (D), boosts the governor pressure up to line pressure level and therefore induces the shift valves of the transmission to assume their respective upshift positions. Further, a valve which by-passes the flow restriction is provided.

Abstract: A final gear train includes a differential case rotatably mounted within a bell shaped portion of a transmission case between it and a bearing retainer attached to the transmission case by means of two bearings, one bearing being disposed at the bottom of the bell shaped portion, the other bearing disposed around a portion of the bearing retainer to rotatably support a final gear attachment portion of the differential case. The final gear attachment portion is in the form of an axially extending annular portion axially extending from a main body portion of the differential case. This bearing arrangement provides a strong radial rigidity to the final gear attachment portion and prevents deformation of the final gear attachment portion during the transmission of torque.

Abstract: A hydraulic control system comprises first and second shift valves which cooperate with each other to effect a shift between two gear ratios. The first shift valve has a port and two different pressure acting areas which are exposed to pressure from the port depending upon downshift and upshift states of the first shift valve, respectively. The second shift valve effects communication between signal pressure generating means and the port of the first shift valve when the second shift valve is in one of two states to deliver the signal pressure to the port of the first shift valve.

Abstract: A hydraulic control system comprises first and second shift valves which cooperate with each other to effect a shift between two gear ratios. The first shift valve has a port and two different pressure acting areas which are exposed to pressure from the port depending upon downshift and upshift states of the first shift valve, respectively. The second shift valve effects communication between signal pressure generating means and the port of the first shift valve when the second shift valve is in one of two states to deliver the signal pressure to the port of the first shift valve. A kickdown pressure generating means delivers a kickdown pressure to the first shift valve.

Abstract: A converter fluid supply passage is situated between a transmission input shaft and a pilot sleeve shaft and a converter fluid return passage is defined between the transmission input shaft and the stationary sleeve shaft extension so that the annular space between the pump drive shaft and the transmission input shaft may be used only as a lockup control passage.

Abstract: The present invention concerns an automatic transaxle wherein connecting passages between an oil pan and a final gear chamber are arranged at a higher level, being formed in the bottom portion of a transmission chamber wall above the oil pan. The transmission chamber also communicates with the final gear chamber. Oil flows between the final gear chamber and oil pan only through the connecting passages so that the oil level in the oil pan will not drop below the level of an oil intake port.

Abstract: In an automatic power transmission for an automotive vehicle, the hydraulic control system has incorporated therein a gearshift timing control arrangement for controlling the overlap and neutral intervals between the timings at which frictional units contributive to predetermined forward drive gear ratios are to be made operative and inoperative, the control being effected depending upon the road speeds of a vehicle.