Honda Giken Kogyo Kabushiki Kaisha

Toshiki Kobayashi

Noriyuki Yamada

Takeya Harada

Tsutomu Saka

Toshihiro Oikawa

Tsuneo Tanai

Takashi Ihara

Keiko Yoshida

Koichi Yoshiki

Mamoru Kosuge

Akira Kaburagi

There is provided a support device for a rocker arm, which is capable of suppressing deformation or wear of a washer, and greatly improving the working efficiency in assembling the washer to the rocker arm. The support device supports the rocker arm having a supported portion, for driving an engine valve of an internal combustion engine. A rocker shaft is supported between a pair of shaft holders arranged in the cylinder head, for pivotally supporting the rocker arm thereon via the supported portion. A washer has engaging pieces, and is attached to one of opposed ends of the supported portion of the rocker arm and one of the shaft holders, in a manner interposed between the opposed ends. The one of the opposed ends is formed with an annular engaging portion for having the washer engaged thereon via the engaging piece.

Support device for rocker arm

Sprockets are fixed to ends of camshafts supported in a cylinder head via camshaft holders, and a timing chain is wrapped around these sprockets. An oil drain hole is provided for supplying relief oil of a hydraulic control valve to the timing chain, and an oil jet is provided for issuing a jet of oil at high pressure from the hydraulic control valve to the timing chain. When the engine is rotating at low speed oil is supplied only through the oil drain hole, and when the engine is rotating at high speed, oil is supplied through both the oil jet and the oil drain hole. The timing chain wrapped around the sprockets of the camshafts can thereby be reliably lubricated according to the operational state of the engine.

Timing chain lubricating system for engine

A valve train for an internal combustion engine includes a rocker shaft ( ) provided with an oil passage, first and second rocker arms ( ) having support parts ( ) provided with bores ( ) to receive the rocker shaft ( ) therein so as to be supported on the rocker shaft ( ) for rocking motion, and a rocker arm interlocking mechanism ( ) for selectively engaging or disengaging the first and the second rocker arms ( ). The first rocker arm ( ) is provided with a pressure chamber ( ) holding a piston ( ) therein, a straight connecting passage connected to the pressure chamber ( ) and an oil passage ( )formed in the rocker shaft ( ). An open end surface ( ) of the bore ( ) of a first support wall ( ) of the rocker arm ( ) is on an axially outer side of the pressure chamber ( ). The straight connecting passage ( ) is inclined to the axis of the bore ( ) so that an imaginary passage ( ) on an extension of the connecting passage ( ) extended toward the open end surface ( ) intersects the open end surface ( ). The outermost side surface ( ) of the first support wall ( ) has an inclined section inclined to the axis of the bore ( ) along the connecting passage ( ).

Valve train for internal combustion engine

In a case member mounting structure for mounting a chain case to an engine body, the chain case is fastened to the engine body by a number of bolts applied along the outer edges thereof and by bolts applied to portions in a central region thereof. The chain case has a plurality of central fastening boss portions in a central region of the inner wall surface, and bolt fastening holes are formed in the respective central fastening boss portions. An annular connection wall is formed in a projecting fashion to connect the central fastening boss portions such that the chain case is affixed to the engine body by putting the connection wall and the central fastening boss portions in abutment with the engine body. As a result, it is possible to fasten the chain case with fewer fastening bolts, enhance the rigidity of the central region of the chain case and prevent its vibrations.

Case member mounting structure

First and second valve-operating characteristic changing mechanisms for changing the valve lift and the valve timing of an intake valve respectively are provided on an intake side of an engine. A hydraulic pressure control valve for the first valve-operating characteristic changing mechanism is mounted on one side of a cylinder head, and an oil filter for the second valve-operating characteristic changing mechanism is mounted on the other side of the cylinder head. The hydraulic pressure control valve and the oil filter are mounted outside a chain cover covering a timing chain. Therefore, the control valve and the oil filter do not interfere with the timing chain, and the maintenance of the control valve and the oil filter is carried out without removal of the chain cover.

Valve operating control system for engine

A pair of valve-timing controlling oil passages leading to a second valve-operating characteristic changing mechanism are defined in a lower camshaft holder, and a valve lift controlling oil passage leading to a first valve-operating characteristic changing mechanism is defined between the pair of valve-timing controlling oil passages in a mating surface of the lower camshaft holder with a cylinder head. In an area where the width of the valve lift controlling oil passage is reduced in order to avoid the interference with the valve-timing controlling oil passages, the depth of the valve lift controlling oil passage is larger than that in the other positions, whereby a sectional area of the oil passage is secured. Thus, the oil passages leading to the first and second mechanisms can be formed compact in a camshaft support member.

Valve operating control system in engine

Camshaft sprockets are fixed to ends of an intake camshaft and an exhaust camshaft supported between a lower camshaft holder and an upper camshaft holder, and a timing chain is wrapped around these camshaft sprockets. A variable cam phase mechanism is provided on the intake camshaft sprocket, and an oil jet that issues a jet of oil for lubricating the timing chain is disposed between the exhaust camshaft sprocket and the lower camshaft holder. The jet of oil issued by the oil jet is directed toward the section where the intake camshaft sprocket is meshed with the timing chain. The oil jet that issues a jet of oil for lubricating the timing chain can thereby be arranged in a compact manner.

Timing chain lubricating structure for engine

Sprockets are fixed to ends of camshafts supported in a cylinder head via camshaft holders. A timing chain is wrapped around these sprockets. The relief oil from a hydraulic control value for controlling a variable valve operating characteristic mechanism passes through an oil passage formed in the plane in which the cylinder head and the camshaft holder are joined and flows out of an oil drain hole, thus lubricating the section where the sprocket is meshed with the timing chain. The section where the sprocket of the camshaft is meshed with the timing chain can thereby be lubricated reliably by a simple structure.

There is provided a construction for a cam rotation sensor attaching portion where a cam rotation sensor is attached which detect the rotation angles of camshafts ( ) supported on cam holders (lower cam holder , upper cam holder ), the construction being characterized in that portions to be detected (projections ) are provided on thrust plates ( ) fixed to axial ends of the camshafts so as to be brought into abutment with an axial end face (a thrust receiving face ) of the cam holder for regulating axial positions of the camshafts, and that a sensor (a proximity sensor ) for detecting the passage of the portions to be detected from an axial direction of the camshafts is attached to a member (a sensor attaching wall ) which is integrated into the cam holder. According to this construction, since the relative positioning accuracy between the portions to be detected and the sensor attaching portion with respect to the axial direction of the camshafts can easily be improved, a high detection accuracy can be obtained. Moreover, since the sensor and the head cover can be attached to and detached from the cylinder head without affecting each other, the maintenance and servicing properties thereof can be enhanced.

Construction for a cam rotation sensor attaching portion

In a valve operating system for an internal combustion engine, wherein connected and disconnected states of cam followers can be switched over from one to another to change the valve operating characteristic of an engine valve, each cam follower includes a cam follower body having a pair of support walls integrally provided thereon and arranged in parallel to sandwich a roller therebetween, and a hollow roller shaft which is fitted and supported at outer peripheries of its opposite ends in through-bores in the support walls, and which has the roller rotatably carried at its intermediate portion. A first groove is defined in an outer peripheral surface of the through-bore in one support wall to extend circumferentially of the through-bore, and a second groove is defined in an outer peripheral surface of the roller shaft at its one end corresponding to the first groove. A C-shaped resilient fastener is mounted in the first and second grooves and is capable of engaging with inner surfaces of the grooves astride them. The switching pin is slidably fitted to inner peripheral surfaces of the roller shafts of adjacent cam followers. With such arrangement, the roller shaft of the rollered cam follower can simply be fixed to the support wall of the cam follower body without caulking equipment, and a protrusion for fixing the roller shaft is not created on an outer surface of the support wall. The roller shaft is also used as a portion of a cam follower connecting mechanism.

Valve operating system for internal combustion engine

In a valve movement control system of an internal combustion engine, a hydraulic operational characteristic variable mechanism with no operational lag or a shortened operational lag on re-starting of the engine is provided. The valve movement control system comprises a camshaft having a cam journal supported for rotation by a support member, a hydraulic operational characteristic variable mechanism provided on the camshaft, an oil pressure control valve, and a control oil passage for supplying operating oil to the operational characteristic variable mechanism through a plurality of members including the camshaft and the support member. An operating oil reserve chamber is provided above the cam journal for supplementing operating oil flowing out through a minute gap between the cam journal and the support member when the engine is stopped.

Valve movement control system of an internal combustion engine

In a valve lift control system for engine intake valves which selectively changes an intake valve lift of an engine, and a phase angle relationship of a timing of opening the engine valve in relation with a crankshaft angle depending on the operating condition of the engine, an arrangement is made to limit the advancing of the opening timing of the engine valve when a large valve lift is selected. It is thus possible to limit the advancing of the timing of opening the engine intake valve only when the valve lift is increased, and the advancing of the timing of opening the engine intake valve may cause an interference between the engine intake valve and the corresponding engine piston. The valve opening timing is otherwise optimized, and the maximum performance of the engine can be attained under all possible circumstances.

Intake valve lift control system

A valve operating system for internal combustion engines comprises a free cam follower which is disposed between first and second drive cam followers operatively connected to engine valves and which is capable of becoming free relative to the engine valves, first and second guide holes respectively provided in the first and second drive cam followers with their axes corresponding to each other. The guide holes is opened to the free cam follower. A double open-ended guide hole is provided in the free cam follower in correspondence to the axes of the first and second guide holes. A first change-over pin is axially slidably received in the first guide hole and adapted to be fitted into the guide hole, and a second change-over pin is axially slidably received in said guide hole with one end thereof abutting against the first change-over pin, and is adapted to be fitted into said second guide hole. A restricting pin is axially slidably received in said second guide hole while being spring-biased toward said second change-over pin, with one end thereof abutting against the other end of said second change-over pin. This construction ensures that fitting of the first change-over pin into the guide hole as well as fitting of the second change-over pin into the second guide hole can be reliably performed.

Valve operating system for internal combustion engines

A drive cam follower operatively connected to an engine valve and a free cam follower capable of becoming free relative to the engine valve are adjacently disposed and adapted to impart in mutually different modes of operation in response to said engine valve rotation of a cam shaft. A connection change-over mechanism is provided between the cam followers and is capable of changing-over the interconnection and disconnection thereof, and resilient biasing means is provided between the free cam follower and the engine body for resiliently urging the free cam follower toward the cam shaft. The resilient biasing means comprises an urging piston slidably received in the engine body for abutment against the free cam follower, and a spring arrangement interposed between the urging piston and the engine body to resiliently bias the urging piston in a direction to abut against the free cam follower. The spring arrangement may comprise series-related springs having different spring constant with one of the springs having a non-linear load characteristic. A vent opening and a lubrication arrangement are provided to facilitate operation of the piston. The urging piston is provided, at its end closer to the free cam follower, with an abutment formed with a smaller diameter to abut against the free cam follower. This facilitates assembly of the resilient biasing means to the engine body, and makes it possible to dispose the resilient biasing means in proximity to a pivoting point of the free cam follower.

Growing community of inventors

Wako, Japan

Toshiki Kobayashi