Abstract: A roller bearing cage (1A) is configured such that a pair of ring parts (4, 6) axially separated from each other is connected by column parts (5) sliding on outer peripheral surfaces of rollers (RA), and pocket holes (P) are evenly formed to store and hold the rollers (RA) in a peripheral wall portion in a circumferential direction. The cage (1A) is manufactured such that a base body (2) including the ring part (4) and the column parts (5) with square columnar convexes (5A) and a connection body (3) including the ring part (6) with square holes (6A) are set as separate members.

Abstract: Present invention relates to provide a cage suited in particular to a supersized roller bearing, which is easy to improve rigidity, realizes a reduction in manufacturing costs, facilitates dimension management and accuracy management, and is less prone to progress abrasion of end surfaces of rollers. A roller bearing cage (1A) is configured such that a pair of ring parts (4, 6) axially separated from each other is connected by column parts (5) sliding on outer peripheral surfaces of rollers (RA), and pocket holes (P) are evenly formed to store and hold the rollers (RA) in a peripheral wall portion in a circumferential direction. The cage (1A) is manufactured such that a base body (2) including the ring part (4) and the column parts (5) with square columnar convexes (5A) and a connection body (3) including the ring part (6) with square holes (6A) are set as separate members.

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: 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: A method for manufacturing according to the present invention includes a step of obtaining a bent workpiece 13 with prepared apertures 21 and 21, wherein the bent work piece 13 includes a pair of side walls 20 and 20 disposed in parallel with each other and connecting walls 30 and 40 for connecting the side walls 20 and 20, the pair of side walls 20 an d20 each having a prepared aperture 21, and a step of forming a roller supporting shaft fixing aperture 25 by inserting a sizing punch 60 into the prepared aperture 21, wherein the sizing punch 60 has a tapered push enlarging portion 61 at a tip end portion, a basal end side of the push enlarging portion being larger than the prepared aperture 21 in diameter, and a tip end side of the push enlarging portion 61 being smaller than the prepared aperture 21 in diameter, whereby the push enlarging portion 61 causes plastic flow of an inner peripheral portion of the prepared aperture to finish the inner peripheral surface of the prepared aperture to thereby obtain a

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: A rocker arm 6 that is rockably attached to a cylinder head 1 actuates a valve 4 by means of a guide groove 73b that is formed at an end thereof engaging with an upper end of a valve stem 41, and a roller 8 that is mounted in a roller housing portion 72 of the arm main unit 7 contacting against a cam 31 and rocking. The guide groove 73b is formed by press working ends of the arm main unit 7 in the thickness direction of the plate material to form a pair of walls 73d, and thereafter applying sandwiching pressure in the lateral direction to the walls 73d to increase the height thereof.

Abstract: A method for manufacturing according to the present invention includes a step of obtaining a bent workpiece 13 with prepared apertures 21 and 21, wherein the bent work piece 13 includes a pair of side walls 20 and 20 disposed in parallel with each other and connecting walls 30 and 40 for connecting the side walls 20 and 20, the pair of side walls 20 an d20 each having a prepared aperture 21, and a step of forming a roller supporting shaft fixing aperture 25 by inserting a sizing punch 60 into the prepared aperture 21, wherein the sizing punch 60 has a tapered push enlarging portion 61 at a tip end portion, a basal end side of the push enlarging portion being larger than the prepared aperture 21 in diameter, and a tip end side of the push enlarging portion 61 being smaller than the prepared aperture 21 in diameter, whereby the push enlarging portion 61 causes plastic flow of an inner peripheral portion of the prepared aperture to finish the inner peripheral surface of the prepared aperture to thereby obtain a