Denso Corporation

Nippondenso Co., Ltd.

Toyota Jidosha Kabushiki Kaisha

Nippon Soken, Inc.

Densco Corporation

Michio Adachi

Akihiko Takenaka

Masayasu Ushida

Yasushi Morii

Kazutoshi Iwasaki

Kenji Ueda

Yoshihito Moriya

Osamu Sato

Masaomi Inoue

Takayuki Inohara

Haruyuki Obata

Isao Hattori

Hisashi Kayano

Masaaki Shinojima

Yoshio Matsumoto

Yasushi Sugiura

Tomomasa Oonishi

Kouichi Toyama

Teruki Kataoka

Isamu Inai

Hiroyuki Yamazaki

Shunsuke Fukaya

A valve timing adjusting device adjusts valve timing by shifting rotational phase of a camshaft relative to a crankshaft. The device has an electric motor for rotating a rotor member that drives and moves a phase defining member to a required position. The phase defining member defines the rotational phase of the camshaft in accordance with the position itself. The phase defining member may be a planetary gear rotatably supported on an eccentric shaft as the rotor member. The planetary gear works as both a reduction mechanism and a phase shifting mechanism. The phase defining member may be a control pin slidably supported on a rotatable member as the rotor member. A planetary gear may be additionally used as the reduction mechanism for rotating the rotatable member. It is possible to control the phase with high accuracy and durability.

Valve timing adjusting device

Upon transmission of a first torque from a first brake portion to a first eccentric shaft, the first eccentric shaft rotates in a retarding direction relative to a rotating member. This causes a first planetary gear to rotate in an advancing direction together with a first output shaft and a driven shaft. Upon transmission of a second torque from a second brake portion to a second eccentric shaft, the second eccentric shaft rotates in a retarding direction relative to the rotating member. This causes a second planetary gear to rotate in the advancing direction together with a second output shaft and the first eccentric shaft, relative to the rotating member, while maintaining rotation in the advancing direction relative to the second eccentric shaft and causes the first planetary gear to rotate in the retarding direction together with the first output shaft and the driven shaft relative to the rotating member.

Valve timing adjusting apparatus

A spool is moved by controlling the amount of electric current supplied to a linear solenoid of a changeover valve, and selects any one of valve sections. The state of communication between fluid passages connected to the changeover valve is determined by the valve section and selected. With the selection of the valve section, the hydraulic fluid is discharged from the advance oil pressure chamber while being supplied to the advance oil pressure chamber, and also is discharged from the retard oil pressure chamber. The oil pressure in the advance oil pressure chamber remains low even when the oil is filled in the advance oil pressure chamber.

A variable valve timing adjuster with an intermediate lock mechanism learns a lock position and a lock release control. During a lock control, a learning of the lock position from a real camshaft phase is repeated to update the learned value, and the learning is ended when it is judged that the learned values have converged. At this time, when the learned values of the lock position do not converge even if the number of learning of the lock position exceeds a predetermined value, an insufficient lock state is judged, and the learned value of the lock position is set to an initial value or the learned value at the previous lock control thereby to make a lock release control. During the lock release control, on the other hand, the control (or the lock release control) of a hydraulic control valve is learned. When the lock cannot be released during the lock release control, the lock release control (or the learned value) is corrected in a direction to facilitate the lock release. When the correction of the lock release control is repeated a predetermined or more number of times or when the lock release control goes outside a predetermined range, the lock release failure is judged.

Variable valve timing control system

A cylindrical bush is provided at the distal end of an oil distributor inserted from the front cover side of a housing to prevent pressure oil from leaking from hydraulic chambers via a clearance formed between the hydraulic chambers and the housing. Further, sealing members are provided on both sides in the axial direction of a connecting section between an oil passage for supplying pressure oil to advancing hydraulic chambers and the oil distributor. The sealing members prevent a leakage from the connecting section.

Variable valve timing mechanism

A valve timing adjusting apparatus that selectively controls a restraint mechanism for restraining relative rotation between a housing member and a vane member to increase the operational life thereof. When a vane rotor is held at a most lagging angular position, an end holding mode is executed to pull out a stopper piston from a stopper hole by fluid pressures of both a leading angle side and a lagging angle side. As a result, when the vane rotor rotates from the most lagging angular position to the leading angle side, torsional forces on the stopper piston and the stopper hole can be minimized as the vane member direction of rotation changes. Since a fluid pressure has already been applied to each of leading angle fluid pressure chambers in the end holding mode, the vane rotor can be rotated from the most lagging angular position to the leading angle side quickly by increasing fluid pressure applied to each of the leading angle fluid pressure chambers without the need to switch a fluid path. In addition, since the fluid pressure applied to each of the leading angle fluid pressure chambers in the end holding mode is smaller than fluid pressure for rotating the vane rotor to the leading angle side, generation of impact sound due to collisions of vanes can be avoided.

Valve timing adjusting apparatus for internal combustion engines

In a rotational phase adjusting apparatus which may be used for controlling opening/closing timings of intake and exhaust valves of an internal combustion engine, one side wall of a housing is fixed to one of a driving member and a driven member, while the other side wall of the housing is made integrally with a circumferential wall of the housing. A seal made of a material less harder than the housing is provided between the housing and a vane. The housing is made of an aluminum while the seal is made of a PPS resin mixed with an inorganic filler. The inorganic filler is harder than the PPS resin but less harder than the housing to reduce wear of the housing.

Rotational phase adjusting apparatus resin seal

A valve timing control apparatus which regulates the movement of an abutting portion in a constraint-free state and prevents the collision between the abutting portion and other members to thereby suppress the generation of hammering sounds. A stopper piston constrains relative rotation between a shoe housing and a vane rotor by being fitted into a taper hole at its most lagged position. Oil pressure chambers apply an oil pressure to the stopper piston in a constraint release direction between the stopper piston and the taper hole. At the most lagged position, a back pressure chamber communicates with an oil lubrication space through communication passages. When the vane rotor is rotated from the most lagged position to an advanced side relative to the shoe housing, the pressure receiving area of a forward end portion of the stopper piston in contact with the oil pressure chamber decreases. On the other hand, communication between the communication passages is interrupted. As a result, the collision of the stopper piston against other members in the constraint-free state is suppressed and the generation of hammering sounds is suppressed.

Valve timing control apparatus for internal combustion engine

In a vane-type rotational phase adjusting apparatus used for adjusting opening/closing timings of an intake valve or an exhaust valve of an engine, a housing unit driven by a driving shaft has a fan-shaped accommodating chamber between adjacent two of a plurality of shoes arranged circumferentially. A vane unit for driving a driven shaft is disposed in the housing unit with its vanes being disposed in the corresponding one of the accommodating chamber so that the rotational phase of the driven shaft is adjusted by the pressure of fluid in the accommodating chamber. Recesses are formed as fluid reservoirs in a cross-sectionally half circle shape on the circumferential end walls of the shoes to hold the operating fluid therein when the housing unit and the vane unit are at rest because of engine stop.

Rotational phase adjusting apparatus having fluid reservoir

In a rotational phase adjusting apparatus which may be used for adjusting valve timing of an engine, a stopper piston is set engageably into and disengageably from a tapered hole of a shoe housing so that relative pivotal motion between the shoe housing and a vane rotor is constrained at the most retarted position. A hydraulic pressure chamber communicates with a retard-side hydraulic pressure chamber while a hydraulic pressure chamber communicates with an advance-side hydraulic pressure chamber. A pressurized area of the stopper piston receiving hydraulic pressure from the hydraulic pressure chamber in a direction of releasing constraint is set to be larger than a pressurized area of the stopper piston receiving hydraulic pressure from the hydraulic pressure chamber in the direction of releasing constraint. When working oil is supplied to the advance-side hydraulic pressure chamber from a state where the stopper piston is fitted into the tapered hole, the stopper piston is drawn out from the tapered hole assuredly even in the case of low hydraulic pressure.

Rotational phase adjusting apparatus having stopper piston

According to the present invention, in a valve timing adjustment device, an arc-shaped gears are assembled alternately on a piston in the peripheral direction. A spring biases an annular member and the arc-shaped gear in the direction as to be away from the piston. A pin is press-fitted into a retainer ring. A spring biases the arc-shaped gear toward the retainer ring, that is, in the direction as to be closer to the piston. An annular member, an annular groove, the head of the pin, a cap, and a containing hole function as a hydraulic damper, respectively. Accordingly, the collision speed of the annular member with the piston accompanied by the movement of the arc-shaped gears, and the piston and the collision speed of the head of the pin with the piston are slowed down. In this way, the respective collision noises can be reduced.

Valve timing adjustment device for internal combustion engine

A valve timing control system for an internal combustion engine includes a valve timing varying mechanism having a camshaft for driving an intake or exhaust valve, a hydraulic piston for varying an angular phase of the camshaft relative to an engine crankshaft, and valve timing advancing and retarding hydraulic pressure chambers for determining a position of the hydraulic piston. The valve timing control system further includes a control valve for controlling hydraulic pressures to be applied to the hydraulic pressure chambers. The control valve includes a sleeve and a spool slidably received in the sleeve. The sleeve is formed with a plurality of openings which, in cooperation with the spool, selectively establish and prohibit communication of the hydraulic pressure chambers relative to high and low pressure sides. Each of the openings is in the form of a groove and extends partially along the circumference of the sleeve. Arrangement of these openings is such that the adjacently arranged openings of at least one pair are offset relative to each other by 180 degrees in a circumferential direction of the sleeve and by a given small distance in an axial direction of the sleeve.

Valve timing control system for internal combustion engine

Vane type angular phase adjusting device

To realize a highly reliable feedback control of the valve timing, i.e., angular rotational relation between a crankshaft and a camshaft, three reference signals are generated from the crankshaft side, and three cam signals corresponding to three pulse inductors arranged at even angles to the camshaft or arbitrary angle intervals to the camshaft are generated from the camshaft side. The variation in the phase difference of each cam signal to each reference angle signal caused by the installation position of the corresponding pulse inductors is stored in a memory as compensation values indicating differences from the phase difference used as a reference. When the signals are detected, the corresponding compensation value for the phase differences other than those used as reference is read out, added and compensated. Based on the relation of the compensated phase difference and a target value of the valve timing, the rotational phase of the crankshaft and the camshaft is controlled.

Valve timing control system for engines

In a valve timing control device, when a camshaft is retained relative to a timing pulley, a hydraulic piston is applied with a force which moves it in a direction toward an advancing-side hydraulic chamber (i.e., in the direction to vary a valve timing to a delaying side) owing to reaction of the driving torque of the camshaft. This force causes fluid to leak out of the advancing-side hydraulic chamber, and the hydraulic piston is liable to move toward this hydraulic chamber. However, fluid of an amount corresponding to an amount of this leakage is supplied to the advancing-side hydraulic chamber by way of a control valve. Also, discharge of fluid from a delaying-side hydraulic chamber via the control valve is stopped. Thus, the movement of the hydraulic piston toward the advancing-side hydraulic chamber when the hydraulic piston is retained at a desired position is prevented. Therefore, the hydraulic piston can be stably retained at the desired position, and a desired valve timing can be maintained.

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Obu, Japan

Michio Adachi