Aisin Aw Co., Ltd.

Takayuki Hisano

Kazumasa Tsukamoto

Masahiro Hayabuchi

Akitomo Suzuki

Masaaki Nishida

Satoru Kasuya

Hiroshi Tsutsui

Kenichi Tsuchida

Takahiro Inoue

Nobutada Sugiura

Toshiyuki Mae

Tatsuya Iida

Hiroshii Tsutsui

Atsuki Ikeda

A hydraulic control apparatus for an automatic transmission including a hydraulic pressure source, hydraulic paths, hydraulic servos for operating friction elements which are coupled with the hydraulic source an the hydraulic paths, a control device arranged on the hydraulic paths for operating engagement release through supply/removal of hydraulic pressure to the hydraulic servos and valves which are arranged on the hydraulic path for cutting off hydraulic pressure from the hydraulic pressure source to the hydraulic servo with hydraulic pressure in the downstream side of the control device as signal pressure.

Hydraulic control apparatus for an automatic transmission

To make it possible to maintain speeds during failures in an automatic transmission that does not have exclusive friction elements corresponding to the attainment of each speed. The hydraulic control apparatus of an automatic transmission, provided with control means for supplying regulated pressure to each of the hydraulic servos that are first through fourth friction elements to which hydraulic pressure is supplied from the oil path L , and provided with switching valves ( )-( ) for cutting off the supply of hydraulic pressure to friction elements other than the friction elements that engage in each speed, on the upstream side of the supply paths L , L , L , L and L . Each switching valve is switched by hydraulic pressure (C -C , B pressures) regulated by the control means that achieve regulated pressure operating conditions during failures, and selective application of signal pressure (Sol, SolB, SoIC pressures) output by the control means as operating means. In a speed that has been attained, the supply path to friction elements that are not to be engaged is cut off. Through this, even during failures the regulated pressure action of the control means corresponding to friction elements that are not to be engaged is ineffective, so the speed that has been attained is fixed.

A hydraulic control apparatus for automatic transmissions, capable of adapting the apparatus to a change in the specifications for a lockup clutch which causes the relationship between the supplying and discharging of a hydraulic pressure for a lockup control operation to be reversed with respect to the connection of oil passages. A valve body of the hydraulic control apparatus is formed by laminating at least two members on each other, and has a valve for regulating a hydraulic pressure supplied to a lockup clutch of a hydraulic transmission unit, a control unit for applying a signal pressure to the pressure regulating valve, a source pressure oil passage for supplying a basic pressure for a pressure regulating operation, and drain oil passage communicated with a drain port. The pressure regulating passage is provided at both sides of a port, which communicates with a lockup oil chamber via an oil passage, with a port communicating with an oil passage, and a port communicating with another oil passage. The openings of the oil passages provided in one member of the valve body are provided so as to overlap respectively both the openings of the source oil passage and drain oil passage provided in the other member thereof. The communication relationship between the two oil passages and the source pressure oil passage and drain oil passage is changed by the communication ports and closing portions of a separator plate inserted between the two members of the valve body.

Hydraulic control apparatus for automatic transmissions

A hydraulic control system includes switching mechanisms for receiving as a signal pressure a hydraulic pressure which is output from each shifting mechanism when all units of the shifting mechanisms are caused to output a hydraulic pressure, and being responsive to the reception of the signal pressure to be switched to a predetermined state for blocking a hydraulic-pressure supply path to specific hydraulic servos, thereby achieving a specific speed out of a plurality of speeds; and supply switching mechanisms provided in a hydraulic-pressure supply path to a hydraulic servo which is not included in the specific hydraulic servos, for switching between supply and cut-off of the hydraulic pressure to the hydraulic servo so as to assure two speeds in the event of the signal failure in a hydraulic control system for individually controlling engaging elements in an automatic transmission by using electric signals.

Hydraulic control system of automatic transmission

A structure in which a hydraulic-pressure control applied pressure for controlling each engagement element of an automatic transmission is realized by using an electric signal such that combinations of engagement which encounter a tie-up in case of a failure of the signal lead to interlocking are inhibited to prevent deterioration in the durability of each engagement element. An automatic transmission incorporates a planetary gear transmission mechanism using selective engagement of at least five engagement elements to realize six gear ratios, and a hydraulic-pressure control apparatus for controlling the engagement elements of the transmission mechanism. Valves are provided which inhibit combinations of engagement of two or more engagement elements of the five engagement elements for interlocking the transmission mechanism.

Hydraulic pressure control apparatus for automatic transmission

A hydraulic control system includes switching mechanisms for receiving as a signal voltage a hydraulic pressure which is output from each shifting mechanism when all units of the shifting mechanisms are caused to output a hydraulic pressure, and being responsive to the reception of the signal pressure to be switched to a predetermined state for blocking a hydraulic-pressure supply path to specific hydraulic servos, thereby achieving a specific speed out of a plurality of speeds; and supply switching mechanisms provided in a hydraulic-pressure supply path to a hydraulic servo which is not included in the specific hydraulic servos, for switching between supply and cut-off of the hydraulic pressure to the hydraulic servo so as to assure two speeds in the event of the signal failure in a hydraulic control system for individually controlling engaging elements in an automatic transmission by using electric signals.

A rotational direction of a rotational element at a high speed gear stage is different from a operational direction of a reaction torque at a low speed gear stage. The rotation by the reaction torque at the low speed gear stage is stopped with a self-energizing operation of a band brake operated by a hydraulic servo. A waiting pressure, which is lower for a predetermined amount than a engagement pressure at the self-energizing operation, and with which a basis of a racing amount occurs after a synchronizing point, is applied to the hydraulic servo until the synchronization is determined. The waiting pressure increases to the engagement pressure after determining the synchronization so that the rotational element is stopped gradually as preventing a long shift time.

Control system for automatic transmission

A lubricant control apparatus for an automatic transmission including a lubricating unit for feeding the lubricating oil to the portions of a speed change mechanism so that the heat to be generated in the speed change mechanism may be absorbed and recovered by the lubricating oil. The lubricant control apparatus includes a detector that detects the acting state of the speed change mechanism; a determiner that determines a necessary lubricating oil flow on the basis of the calorific value in the speed change mechanism, the calorific value being calculated from the detected acting state of the speed change mechanism; and a structure for feeding the lubricating oil to the speed change mechanism on the basis of the determined necessary lubricating oil flow. The lubricant control apparatus feeds an optimum lubricating oil flow according to the acting state of the speed change mechanism.

Lubricant control apparatus for automatic transmission

A control system for a vehicular automatic transmission includes a speed change mechanism including an output element that is connected to the drive shaft of a vehicle to transmit power, and a rotary element connected to the output element. A control system for the speed change mechanism is also provided. The control system includes a hydraulic servo actuated brake for retaining the rotary element to check the rotation of the output element in a vehicle roll back direction. The brake includes a band brake that establishes different application forces depending on whether the brake operates by a self-energizing action or a de-energizing action according to the rotational direction of the rotary element. The band brake is set so that the rotary element rotates during backward rotation of the output element in the direction of the self-energizing action, and is set with a first oil pressure necessary for retaining the rotary element during backward rotation of the output element caused by the roll back of the vehicle. The first oil pressure is lower than a second oil pressure necessary for retaining the rotary element during operation of the band brake by the de-energizing action. The control system further includes an oil pressure feeder for feeding the hydraulic servo of the band brake with an oil pressure which is equal to or higher than the first oil pressure and lower than the second oil pressure.

Automatic transmission with anti-rollback band brake pressure control

To optimize the application hydraulic pressure of the friction application elements in the transmission mechanism, and to reduce the unnecessary load on each member, the transmission mechanism of an automatic transmission is provided with a plurality of friction application elements which are applied simultaneously in order to achieve the designated gear stage, and hydraulic servos which operate the friction application elements independently. The control apparatus has an information detecting means, an input torque calculating means which calculates the input torque of the transmission mechanism on the basis of this information, an application hydraulic pressure calculating means which calculates the necessary application hydraulic pressure required to maintain the application of each individual friction application element on the basis of the input torque, and a supply means which supplies the necessary application hydraulic pressure to the hydraulic servos of the friction application elements. The supply means makes the hydraulic pressure supplied to each hydraulic servo the necessary application hydraulic pressure calculated for each friction application element independently when achieving the designated gear stage.

Control apparatus for automatic transmissions

Uncomfortable travel of a vehicle due to engine brake actions during the travel of the vehicle in traffic is prevented without using an one-way clutch within a transmission mechanism. An automatic transmission is composed of rotational elements that are braked at the time of establishing low stages, a brake that brakes the rotational elements, and control systems which control the oil pressure of the hydraulic servo in the brake. A band brake that creates differences in application forces, using self-energizing and deenergizing actions, serves as the brake, which is set to have an area in which the oil pressure during the drive is lower than the oil pressure during the non-drive, by setting the self-energizing direction as a direction of rotation of the rotational element during the drive and the deenergizing direction as an opposite direction of rotation of the rotational element during the non-drive. The control systems have a supplying mechanism which supplies oil to the hydraulic servo of the band brake at an oil pressure that is lower than the oil pressure during the non-drive and is equal to or higher than the oil pressure during the drive.

Control mechanism for automatic transmission

In order to improve transmission efficiency of an automatic transmission, an engagement brake which does not cause drag is used and the surety of its engagement and release, and quick switching between forward maneuver and backward maneuver, is enabled. The automatic transmission comprises a transmission mechanism to achieve forward maneuver and backward maneuver. A backward motion brake which stops the rotation element to achieve backward maneuver is the engagement brake and an input clutch to transfer power by meshing with the rotation element during both forward maneuver and backward maneuver is a friction clutch. The control apparatus executes the control operation to prepare for speedy re-meshing by holding a supply pressure for the clutch hydraulic servo at a sufficient oil pressure to place the pressure in the stand-by condition at the piston stroke position immediately before the start of clutch engagement during the engagement or releasing of engagement of the engagement brake at the time of D.fwdarw.R or R.fwdarw.D shift.

Control apparatus for an automatic transmission

A control system for use in an automatic transmission having a transmission mechanism for establishing a plurality of forward stages, a neutral state and a reverse stage. The transmission mechanism includes a predetermined rotary element to be retained for establishing the reverse stage; a reverse brake for retaining the rotary element; and a frictional engagement element capable of stopping the rotation of the rotary element. The reverse brake is a meshing type brake which meshes with and retains the rotary element. The control system has an engagement mechanism for applying the frictional engagement element. When the reverse stage is selected, the frictional engagement element is applied at least until the meshing engagement of the reverse brake is established, to stop the predetermined rotary element.

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Anjo, Japan

Takayuki Hisano