Abstract: A lifter structure applied to an internal combustion engine and is actuated by a cam, includes a cylindrical lifter guide, a lifter body reciprocally moved in the guide while sliding on an inner circumferential surface of the guide, with drive of the cam, a pair of opposed walls continuous to an end of the lifter body, a pin extending through holes of the opposed walls and having two ends swaged onto outer surfaces of the opposed walls respectively, a roller disposed between the opposed walls, plural swaging side regions located at the same sides of the outer circumferential surface of the lifter body as the outer surfaces of the opposed walls, plural swaging side opposite regions located opposite the swaging side regions respectively, and plural escape recesses formed in the swaging side opposite regions so as to be spaced from the swaging side regions respectively.

Abstract: The present invention provides a variable valve mechanism that varies amounts of opening and closing of a valve includes a rotating cam, a rocker arm, two lash adjusters, a hydraulic passage, and a switching mechanism. The rocker arm includes an input member and an output member. The two lash adjusters support the rocker arm so that the rocker arm can rock. The hydraulic passage includes an internal oil passage that is provided in an interior of at least one of the lash adjusters, and an arm oil passage that is provided in an interior of the rocker arm and that is connected from the internal oil passage. The switching mechanism uses a hydraulic pressure in the hydraulic passage to perform a switching between a linked state and a released state, and the switching varies the amounts of the opening and the closing of the valve.

Abstract: It is an object of the present invention to provide a rotor shaft capable of sufficiently securing a fastening strength between an inner shaft and an outer shaft, obtaining an excellent anti-rotation torque, and reducing a weight of the rotor shaft. A rotor shaft 3 is divided into an inner shaft 4 and an outer shaft 5. The inner shaft 4 includes a tip end portion 41, a rear end portion 43, and a thick portion 42. The thick portion 42 connects the tip end portion 41 and the rear end portion 43 with each other in the radial direction, and has the same inner diameter as that of the tip end portion 41 and the same outer diameter as that of the rear end portion 43. The outer shaft 5 includes an inner cylindrical portion 51, a magnetic body-mounting outer cylindrical portion 53, and a flange 52 that connects the inner cylindrical portion 51 and the magnetic body-mounting outer cylindrical portion 53 with each other.

Abstract: A rocker arm unit constituting a valve gear of an internal combustion engine includes a support member assembled into the cylinder head, a rocker arm supported on a top of the support member so as to be swung with a supported position serving as an approximate fulcrum, and a wire member bridging the support member side and the rocker arm side with each other thereby to connect the support member and the rocker arm together.

Abstract: A rocker arm unit comprises a lash adjuster having a plunger extending axially and a cylindrical body which houses the plunger so that the plunger is slidable; a rocker arm supported by an upper end of the plunger and swung with the supported position serving as a pivot; and a clip which is fixed to the body so as to extend from the fixed position to engage the rocker arm, thereby restricting drop of the rocker arm out of the lash adjuster.

Abstract: A return spring is formed using a compression coil spring that is installed so that its axial direction is an up-down direction. The return spring is provided in a high-pressure chamber, and powers a plunger in an upwards direction. A coil diameter of the return spring varies along the axial direction. When the return spring is in a maximally compressed state, an axial direction dimension (up-down direction dimension) is smaller than a dimension that is a thickness of a spring wire multiplied by the number of coil turns. Hence, an overall height of a lash adjuster A can be reduced in comparison to when a return spring with a constant coil diameter over an entire length is used.

Abstract: The present invention provides a rocker arm manufacturing method capable of improving the durability and excellent in productivity. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and one end side connection wall 30 connecting lower ends of a longitudinal one end of both the side walls is obtained. Next, both side walls 20 formed at the one end of the intermediate product 13 are inwardly bent. Thereafter, ironing dies 60 are pressed down against outer surfaces of both the inclined side walls 20 from an upper side to a lower side to execute ironing of outer surface portions of both the side walls 20 to downwardly plastically fluidize the constituent material of both the side walls 20 to thereby form valve stem guide walls 35 at both sides of the one end side connection wall 30 in a downwardly protruded manner.

Abstract: A rocker arm installed module 1 is constructed by installing the cam shaft 3, the rocker arm 4 and the pivot 5 to the housing 2. The housing 2 is provided with a drop-off preventing means 21 for supporting and preventing the rocker arm 4, which is disposed on the pivot 5, from dropping off. The rocker arm installed module 1 is constructed by disposing the rocker arm 4 among the cam 31 of the cam shaft 3, the pivot 5 and the drop-off preventing means 21 in the housing 2 to form a module, the module being configured to be disposed in a concave portion 61 of the cylinder head 6 while preventing the rocker arm 4 from dropping off.

Abstract: A cam lobe is formed as a single part, not formed together with a shaft body. The shaft body penetrates through bearing holes, as well as a mounting hole provided in the cam lobe, which is arranged in between adjacent bearing holes. The bearing holes each in a perfect circular shape can be achieved, since there is no need to divide the bearing holes into two semi-circular arc shaped concave portions. Consequently, a camshaft can be supported so as to rotate smoothly.

Abstract: A rocker arm for an internal combustion engine includes a roller brought into contact with a cam thereby to be rotated, an arm body having a storage portion in which the roller is stored, the arm body being swung by rotation of the cam, thereby opening and closing a valve. The storage portion has an opening edge located on an upper surface of the arm body and opposed to a circumferential surface of the roller, and the opening edge includes a part receiving a lubricant flowing along the upper surface of the arm body, the part being formed with a receiving opening edge jutting out so that both widthwise ends thereof are located away from the circumferential surface of the roller and so that a widthwise central portion thereof comes close to the circumferential surface of the roller.

Abstract: A variable valve mechanism includes a low-speed cam, a high-speed cam, a low-speed rocker arm driven by the low-speed cam, a high-speed rocker arm driven by the high-speed cam, and a switching mechanism. A cam profile of the high-speed cam is set such that it does not exceed a cam profile of the low-speed cam. During low-speed operation, the switching mechanism links the low-speed and the high-speed rocker arms such that the low-speed cam causes the high-speed rocker arm to rock together with the low-speed rocker arm and to open and close a valve. During high-speed operation, the switching mechanism de-links the low-speed rocker arm and the high-speed rocker arm such that the low-speed cam causes the low-speed rocker arm to rock idly and the high-speed cam causes the high-speed rocker arm to rock independently and to open and close the valve. The cam profile of the low-speed cam is set such that the valve closes later than it does with the cam profile of the high-speed cam.

Abstract: A rocker arm that is rockably attached to a cylinder head actuates a valve by a guide groove that is formed at an end thereof engaging with an upper end of a valve stem, and a roller that is mounted in a roller housing portion of the arm main unit contacting against a cam and rocking. The guide groove is formed by press working ends of the arm main unit in the thickness direction of the plate material to form a pair of walls, and thereafter applying sandwiching pressure in the lateral direction to the walls to increase the height thereof.

Abstract: The present invention provides a variable valve mechanism which includes a camshaft having a drive cam, a rocker shaft provided parallel to the camshaft, and a variable mechanism that is provided on the rocker shaft and interposed between the drive cam and a valve, and that changes an opening/closing amount of the valve. The variable mechanism includes a main arm that engages with the drive cam, a cam arm that has a cam surface pressing the valve, a control cam that is provided on the rocker shaft, and has an outer peripheral surface whose distance from a shaft center of the rocker shaft varies gradually, and a displacement member whose distance from the shaft center is changed by turning of the control cam. A relative phase between the main arm and the cam arm is displaced as the distance between the displacement member and the shaft center changes.

Abstract: In a process of mounting a camshaft 20 to a supporting member 10, a shaft body 21 is firstly inserted into a first bearing hole 13F in the front side of the supporting member 10, before the shaft body 21 is axially moved toward the second bearing hole 13R. In order to get a cam lobe 22 through a concave bearing portion 13M in a semicircular arc shape, rotation of the camshaft 20 enables a cam nose 22b to be directed downward, which is opposite from the concave bearing portion 13M. This enables avoiding the interference between the cam nose 22b and the concave bearing portion 13M, even when the curvature radius of the concave bearing portion 13M is reduced. Consequently, reduction of the curvature radius of the concave bearing portion 13M achieves the downsizing of the supporting member 10.

Abstract: A hydraulic auto-tensioner includes a high-pressure oil chamber and a low-pressure oil chamber, and oil (L) in the high-pressure oil chamber passes through a clearance (G) between a cylinder (17) and a piston portion (18) of a plunger and leaks into the low-pressure oil chamber from an end of the clearance (G) near an end surface of the cylinder (17). A recessed groove (40) is provided in an inner peripheral surface of the cylinder (17) by a conical surface (41) having a groove angle of 5 to 15 degrees from the end of the clearance (G), a throttle portion (45) projecting onto the piston portion (18) side is provided further toward the end surface side of the cylinder than the groove (40) in the inner peripheral surface of the cylinder (17), and a throttle gap (A) larger than the clearance (G) is formed between the throttle portion (45) and the piston portion (18).

Abstract: The present invention provides a variable valve operating mechanism which includes two valve operating members for opening and closing two valves individually, a drive cam provided on a single camshaft, two swing arms for transmitting a power of the drive cam to the valve operating members individually by swinging about a different axis to the camshaft, and a variable device for modifying a displacement of the swing arm per rotation of the drive cam in accordance with an operating condition of an internal combustion engine. The variable device includes a single control shaft, an actuator for driving the control shaft, and a cam device that operates in conjunction with the control shaft to dissimilate the displacement of the two swing arms.

Abstract: The present invention provides a rocker arm manufacturing method capable of stably forming valve stem guide walls. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and a one end side connection wall 30 connecting lower ends of both the side walls 20 at a longitudinal one end of the product is obtained. Next, a first pressing punch 70 is pressed against the outer surface portions of both the side walls 20 from the outside thereof to cause downward plastic flows of regions of the outer surface portions of both the side walls positioned below the cutout portions 31 to thereby form raising walls 32 in a downwardly protruded manner at both sides of the one end side connection wall 30. Thereafter, valve stem guide walls 35 are formed by pressing second pressing punches 80 against both the raising walls 32 of the one end side connection wall 30.

Abstract: The rocker arm 1 of this embodiment has a pair of side wall portions 21 formed so as to face each other, an engaging portion 22 connecting the pair of side wall portions 21 and adapted to engage with a rocking support member 4 arranged in an engine, a sliding portion 26 connecting the pair of side wall portions 21 and being adapted to be in slidable contact with a stem front end portion 631 of an engine valve 63. The engaging portion 22 has a board surface portion 23 connecting the pair of side wall portions 21 and a protruding portion 24 protruding from the board surface portion 23 toward the rocking support member 4. In the protruding portion 24, a spherical concave portion 25 adapted to engage with a spherical protruding portion 41 of the rocking support member 4 is formed as a depression.

Abstract: A lash adjuster includes a cylindrical bottomed plunger mounted in a cylindrical bottomed body so as to be movable upward and downward and including a high-pressure chamber defined between an underside of the plunger and a bottom wall of the body to reserve an operating oil, a leak path defined by an inner circumference of the body and an outer circumference of the plunger so that the oil reserved in the high-pressure chamber leaks through the leak path with downward movement of the plunger, and a ring-shaped member located between the inner circumference of the body and the outer circumference of the plunger, normally projecting into the leak path and being elastically deformed radially inward or outward with increase in pressure of the oil at the high-pressure chamber side so as to be retreated from the leak path, thereby reducing flow resistance of the oil in the leak path.

Abstract: The present invention provides a rocker arm manufacturing method capable of improving the durability and excellent in productivity. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and one end side connection wall 30 connecting lower ends of a longitudinal one end of both the side walls is obtained. Next, both side walls 20 formed at the one end of the intermediate product 13 are inwardly bent. Thereafter, ironing dies 60 are pressed down against outer surfaces of both the inclined side walls 20 from an upper side to a lower side to execute ironing of outer surface portions of both the side walls 20 to downwardly plastically fluidize the constituent material of both the side walls 20 to thereby form valve stem guide walls 35 at both sides of the one end side connection wall 30 in a downwardly protruded manner.