摘要:
A control system of an automatic transmission includes a torque converter, a lock-up clutch for directly connecting input and output members of the torque converter, a pressure control valve which changes a hydraulic pressure to control an engaging force of the lock-up clutch, and a pressure regulator, disposed in an engaging passage, which supplies hydraulic pressure to engage a frictional element. The pressure regulator adjusts a primary pressure and produces an output hydraulic pressure corresponding to a control pressure introduced into a control port of the pressure regulator. A control pressure supply device is provided for introducing the control pressure, controlled by the pressure control valve, into the control port of the pressure regulator. The number of parts can be reduced without producing any inconvenience.
摘要:
An automatic transmission control system for selectively locking and unlocking a plurality of frictional coupling elements is provided within an automatic transmission so as to place the automatic transmission into one of various possible gears. The control locks a specific one of the frictional coupling elements with locking pressure when the automatic transmission performs a specific gear shift and unlocks it by reducing the locking pressure when causing it to perform, an opposite gear shift reverse to the specific gear shift. The locking pressure is increased by way of a relatively high level of shelf pressure during the specific gear shift and reduced by way of a relatively low level of shelf pressure during the opposite gear shift.
摘要:
A multiple stage automatic transmission includes a main transmission mechanism, a sub-transmission mechanism connected with the main transmission mechanism to for introduction of a torque therefrom, and a frictional element connected with the sub-transmission. The engaging force of the frictional element is changed at least by two steps in accordance with a shift mode without changing a hydraulic pressure applied for actuating the frictional element. A shift shock, therefore, can be obviated.
摘要:
A control system for an automatic transmission has a shift gear mechanism with a plurality of frictional elements, including a low reverse brake which is selectively actuated for switching a power transmitting path to establish a desired shift stage. A hydraulic control circuit controls supply of a hydraulic fluid to and relief of the fluid from an actuator for the frictional element. An accumulator is provided in a hydraulic passage communicated with the low reverse brake for obviating a shock as the low reverse brake is engaged. Back pressure of the accumulator is controlled when a first shift gear stage is established through the engagement of the low reverse brake. A torque shock can be suppressed when the first stage is established in an L-range.
摘要:
A shift control system for an automatic transmission including a shift gear mechanism for providing a plurality of shift stages of different speed ratios, a plurality of frictional elements to be selectively actuated for switching a power transmitting path to establish a desired shift stage, range selecting device for selecting a shift range at least between a forward and a reverse ranges through a manual operation of a driver, control device for providing the shift gear mechanism with a specific shift stage in which an input member and output member of the shift gear mechanism are rotated together with each other in the case where the reverse range is selected during a forward movement and thereafter a forward range is selected again, the specific shift stage being provided for a predetermined time period after the forward range is selected again. A double lock condition of the shift gear mechanism can be avoided.
摘要:
A shift control system of an automatic transmission includes a first element which is to be released in a shift operation, a second element which is to be engaged in the shift operation, and a target shift time set section for setting a target time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element. A shift time calculation section is provided for obtaining an actual time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element, and a releasing pressure control section is provided for receiving output of the target shift time set section and the shift time calculation section for controlling a releasing pressure of the first frictional element in the shift operation based on the difference between the target and actual time periods of the shift operation. An engaging pressure control section is used for controlling an engaging pressure of the second frictional element in the shift operation. A shift shock is effectively suppressed by the shift control system.
摘要:
In an automatic transmission (AT) in which an input shaft (Input) and an output gear (Output) are disposed on the same axis and three clutches (C1-C3) and two brakes (B1, B2) are selectively operated to provide six forward speeds, first and second planetary gear sets (GS1, GS2) are configured to consistently reduce the speed of input rotation and output the speed-reduced rotation, thereby enabling downsizing of them. The first and second planetary gear sets (GS1, GS2) are arranged in a transmission case at both the axial ends thereof. Third and fourth planetary gear sets (GS3, GS4) are connected to each other to have four rotation elements in combination, thereby constituting a Simpson planetary gear train. One of the four rotation elements (a fourth carrier (PC4) in an illustrated example) is connected to the output gear (Output). Rotations input and reduced in speed by the first and second planetary gear sets (GS1, GS2) are input to sun gears (S3, S4) of the third and fourth planetary gear sets (GS3, GS4), respectively. First to third clutches (C1-C3) and a first brake (B1) are arranged to surround the first and second planetary gear sets (GS1, GS2).
摘要:
An automatic transmission has first, second and third gear sets, first and second clutches, and first, second and third brakes. First, second and third sun gears, and a first carrier are interconnected with a second sun gear, a second carrier, a third carrier, an input shaft and an output gear, respectively. The first clutch selectively connects the first sun gear and the second sun gear to the input shaft, and the second clutch selectively connects the first ring gear and the second carrier to the input shaft. The first brake selectively connects the first ring gear and the second carrier to a casing. The second brake selectively connects the second ring gear and the third carrier to the casing, and the third brake selectively connects the third ring gear to the casing.
摘要:
There is provided an automatic transmission comprising a first shaft capable of receiving torque from an engine, and four planetary gear sets arranged coaxially on the first shaft and in series in an axial direction of the first shaft. Each of the four planetary gear sets has a single sun gear and a single ring gear. Further, the automatic transmission comprises an output wheel arranged coaxially on the first shaft, and capable of outputting torque transmitted from the engine through some of the four planetary gear sets. The output wheel is arranged between two of the four planetary gear sets. Accordingly, the noise or vibration from the planetary gear sets in the automatic transmission may be reduced, while the overall length of the first shaft may be made shorter, and the overall size of the automatic transmission may be made smaller.
摘要:
In an automatic transmission (AT) in which an input shaft (Input) and an output gear (Output) are disposed on the same axis and three clutches (C1-C3) and two brakes (B1, B2) are selectively operated to provide six forward speeds, first and second planetary gear sets (GS1, GS2) are configured to consistently reduce the speed of input rotation and output the speed-reduced rotation, thereby enabling downsizing of them. The first and second planetary gear sets (GS1, GS2) are arranged in a transmission case at both the axial ends thereof. Third and fourth planetary gear sets (GS3, GS4) are connected to each other to have four rotation elements in combination, thereby constituting a Simpson planetary gear train. One of the four rotation elements (a fourth carrier (PC4) in an illustrated example) is connected to the output gear (Output). Rotations input and reduced in speed by the first and second planetary gear sets (GS1, GS2) are input to sun gears (S3, S4) of the third and fourth planetary gear sets (GS3, GS4), respectively. First to third clutches (C1-C3) and a first brake (B1) are arranged to surround the first and second planetary gear sets (GS1, GS2).