Honda Motor Co., Ltd.

Denso Corporation

Keihin Corporation

Shunsuke Yoshida

Tomoaki Mukai

Tetsuya Mochizuki

Yutaka Ishikawa

Yuya Tachibanada

Yoshimichi Tsubata

Yuki Ono

Shogo Kobayashi

Itsuki Shimazaki

Hirotaka Yokota

Soichi Sugino

Naohisa Morishita

Shigeto Ryuen

Tatsuya Kitanaka

Tomoyuki Noguchi

Nobuyuki Watanabe

Kenji Suda

Yoshiatsu Asai

Kyohei Takahashi

Kotaro Hiramine

Syu Murayama

Shinichiro Tomoda

Kota Inoue

Isamu Shinbori

Yasunobu Tandai

A hydraulic control apparatus including a first and second control valves switched to exert hydraulic pressure on a piston to press toward first position, a third and fourth control valves switched to exert hydraulic pressure on the piston to press toward second position and, a CPU. The CPU performs executing a first process controlling the control valves so that hydraulic pressure is exerted by switching of the first, second and third control valves or a second process controlling the control valves so that hydraulic pressure is exerted by switching of the second control valve and determining that the first control valve is failed when movement of the piston to the first position is not detected through the first process and determining that the third control valve is failed when movement of the piston to the first position is not detected through the second process.

Hydraulic control apparatus

There is provided an automatic transmission capable of preventing deterioration of driving performance even when an engagement mechanism is not switched due to a failure. An automatic transmission includes a first brake which is always in a fixed state from a first forward gear stage to a predetermined gear stage and is in an open state at a gear stage with a higher speed than the predetermined gear stage, and a hydraulic sensor configured to detect whether the first brake is switched to the fixed state. When a transmission control device instructs the first brake to switch to the fixed state, and it is confirmed that the first brake is in an open state, the transmission control device instructs engagement mechanisms other than the first brake to perform switching so that a preliminary gear stage is able to be set.

Automatic transmission

Provided is a hydraulic pressure control device. A hydraulic pressure control device includes a solenoid valve configured to supply hydraulic pressure to switch between an engaged state and a released state of a lock-up clutch, and a transmission control device configured to control the solenoid valve. The solenoid valve supplies hydraulic pressure to switch between a parking locked state and a parking released state of a parking lock mechanism, in addition to switching of the lock-up clutch.

Hydraulic pressure control device

The lubrication loopincludes a first lubrication flow path L, a release flow path L, a low pressure fluid discharge valve, a return flow path L, and a discharge flow path L. In the low pressure fluid discharge valve, an accumulator pistonis biased to the other end side of a piston housing chamberby a springwhen a pressure of the fluid applied to a piston position control chamberis less than a predetermined pressure so that a supply portand a discharge portcommunicate with each other via a spool groove

Fluid pressure loop

An actuator having sufficiently high detection accuracy while having a simple configuration is provided. An actuator includes a cylinder (), a piston () that moves inside the cylinder (), a stroke sensor () that detects a position of the piston (), an edge portion () that restricts rotation to one side, and a restriction protrusion () that restricts rotation to the other side. The amount of rotation allowed by the edge portion () is larger than the amount of rotation allowed by the restriction protrusion (). A center of a sensor () of the stroke sensor () is shifted to one side from a center of a member to be detected () fixed to the piston ().

Actuator and fluid pressure control circuit having the same

An actuator in which the abrasion of a piston and a cylinder can be prevented and it is difficult for the smooth movement of the piston to be hindered is provided. The actuator includes a cylinder (), a piston () that moves inside the cylinder () according to a supplied fluid pressure, and a detent mechanism () that fixes a position of the piston () until the fluid pressure exceeds a predetermined value. The detent mechanism () includes a first elastic memberand a second elastic memberwhich are arranged to face each other with an axis (a) of the piston () interposed therebetween and press the piston () so as to sandwich the piston () therebetween.

A hydraulic accumulator includes a limiting portion that is fitted into a ring end gap of a snap ring to limit a decrease in a diameter of the snap ring. The snap ring is stamped from a metal sheet by a press machine. Therefore, one of two opposed surfaces of a portion of the snap ring, which is fitted into a groove, forms a sloped surface as a result of shear droop. The limiting portion is fitted into the ring end gap of the snap ring to limit the decrease in the diameter of the snap ring. Thus, it is possible to limit riding of the sloped surface of the snap ring on a corner of the groove, and thereby it is possible to limit removal of the snap ring from the groove.

Hydraulic accumulator and manufacturing method thereof

A parking lock apparatus includes an engaging mechanism, a slider, a hydraulic circuit, and a processor. The engaging mechanism is to prevent a rotation of a rotating body when the engaging mechanism is in a mechanical engagement state. The slider is to switch a state of the engaging mechanism between the mechanical engagement state and a mechanical disengagement state in accordance with a position of the slider. The hydraulic circuit is to change the position of the slider. The processor is configured to increase line pressure in the hydraulic circuit when the engaging mechanism is in the mechanical engagement state.

Parking lock apparatus

An actuator capable of preventing the inside of a cylinder from being scratched is provided. A two-way piston includes a cylinder having an opening, a piston, and a stroke sensor that detects a position of the piston. The stroke sensor includes a stay that extends from a portion exposed from the opening of the piston to the outside of the cylinder, a member to be detected that is attached to the stay, and a sensor that detects a position of the member to be detected. The piston including a fixing hole having a depth smaller than a diameter of the piston in the portion exposed from the opening. The stay is fixed by a bolt that is inserted into the fixing hole.

A parking lock apparatus includes a parking gear rotatable together with a rotating body of a transmission. A slider is to be switched between a parking lock position in which a parking pawl is in engagement with the parking gear and a parking release position in which the parking pawl is out of engagement with the parking gear. A hydraulic circuit includes a third oil passage through which a first line pressure is applied to push the slider toward the parking release position, a fourth oil passage through which a second line pressure is applied to push the slider toward the parking lock direction, and a hydraulic cut valve provided in the third oil passage to be opened when a difference between the first line pressure and the second line pressure is higher than or equal to a threshold pressure when applying line

In a vehicular parking lock device, the parking lock is actuated when a line pressure is supplied to a left end of a hydraulic actuator () via a second solenoid valve (A), or a hydraulic pressure of an accumulator () is supplied to the left end of the hydraulic actuator () via a third solenoid valve (B), and the parking lock is released when a line pressure is supplied to a right end of the hydraulic actuator () via a first solenoid valve (C,D). The second solenoid valve (A) and the first solenoid valve (D) also function as a solenoid valve that supplies the hydraulic pressure to a torque converter () and a solenoid valve that supplies the hydraulic pressure to a hydraulic brake () for shift change, respectively. Thus, it is possible to decrease the total number of solenoid valves, thereby cutting the number of components of a hydraulic circuit ().

Vehicular parking lock device

A check valve includes a check valve body and a check valve member. The check valve body includes a check valve outlet port and a check valve oil path. The check valve member is movable in the check valve oil path to move in a first direction in which the check valve member is pushed by hydraulic fluid due to hydraulic pressure from a hydraulic pump. A switching valve includes a switching valve body. The switching valve body includes a switching valve inlet port connected to the check valve outlet port and a receiving surface facing the check valve outlet port. The check valve member contacts the receiving surface after the hydraulic pump starts providing hydraulic pressure. The switching valve body is supported by a valve body via a first O-ring and a second O-ring such that the switching valve body is movable in the first direction.

In a vehicular parking lock device, supplying a hydraulic pressure from pressure regulation of a line pressure by a linear solenoid valve to a hydraulic brake via a switching valve operated by a first solenoid valve enables a transmission to carry out a shift change. If desired that a parking lock is not operated when an engine stops, the hydraulic pressure stored under pressure in an accumulator is discharged to a drain oil passage by connecting the linear solenoid valve selectively to the drain oil passage by the first solenoid valve, thereby making it possible to prevent the hydraulic pressure stored under pressure in the accumulator from being supplied to a locking oil chamber at the other end of the hydraulic actuator. The first solenoid valve is used for both controlling the operation of the hydraulic brake and discharge of the hydraulic pressure stored under pressure in the accumulator.

A hydraulic control device for an automatic transmission includes a cut-off valve and a line pressure detector. The cut-off valve has a valve element located at one of a first position and a second position. The first position disables supply of a hydraulic fluid to a frictional engagement mechanism of the automatic transmission. The second position enables supply of the hydraulic fluid to the frictional engagement mechanism. The line pressure detector is configured to detect a line pressure. The cut-off valve is to control a hydraulic fluid passage so that the line pressure is supplied to the line pressure detector in a case where the valve element is at the first position and so that the line pressure is not supplied to the line pressure detector in a case where the valve element is at the second position.

Hydraulic control device for automatic transmission

In case of power supply loss, a parking lock is operated by moving a piston of a hydraulic actuator rightward by use of hydraulic pressure accumulated in an accumulator. If a hydraulic pressure generating source becomes unable to generate line pressure due to its failure after the power supply loss, it is desirable that the parking lock be releasable to tow a vehicle, for example. In that time, because the hydraulic pressure in the accumulator has got out via an orifice, the parking lock can be released by moving the piston in the hydraulic actuator leftward by use of a manual operation device without interruption by the hydraulic pressure accumulated in the accumulator. Because the hydraulic pressure in the accumulator is automatically released via the orifice, a complicated mechanism for enabling the manual operation device to work without interference from the hydraulic actuator becomes unnecessary.

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Wako, Japan

Shunsuke Yoshida