TURNING TOOL, METHOD FOR MANUFACTURING A PISTON, AND PISTON

Abstract

A turning tool (20) for forming a plurality of groove portions (17) on an outer surface (11) of a skirt portion (10) of a piston (1) that slides along an inner wall surface of a cylinder bore of an engine, wherein the turning tool (20) comprises a mounting portion (21) that includes a mounting hole (22) for attachment to a lathe and extends such that it crosses a tool feed direction of the lathe, and a cutting edge portion (23) provided at a distal end of the mounting portion (21), wherein a distal end of the cutting edge portion (23) includes an arcuate cutting edge portion (24) designed to machine the groove portion (17) and a linear cutting edge portion (25) that extends parallel to the tool feed direction and is designed to machine the intermediate surface portion (18), characterized in thatthat the arcuate cutting edge region (24) and the linear cutting edge region (25) are arranged adjacent to each other such that the linear cutting edge region (25) is located on a front side in the tool feed direction relative to a hole center of the mounting hole (22).

Claims

[1] Turning tool (20) for forming a plurality of groove portions (17) on an outer surface (11) of a skirt portion (10) of a piston (1) sliding along an inner wall surface of a cylinder bore of an engine, wherein the turning tool (20) comprises a mounting portion (21) including a mounting hole (22) for attachment to a lathe and extending so as to cross a tool feed direction of the lathe, and a cutting edge portion (23) provided at a distal end of the mounting portion (21), wherein a distal end of the cutting edge region (23) includes an arcuate cutting edge region (24) designed to machine the groove region (17) and a linear cutting edge region (25) extending parallel to the tool feed direction and designed to machine the intermediate surface region (18), characterized by , that the arcuate cutting edge portion (24) and the linear cutting edge portion (25) are arranged adjacent to each other such that the linear cutting edge portion (25) is located on a front side in the tool feed direction relative to a hole center of the mounting hole (22). [2] Turning tool (20) according to claim 1, wherein the linear cutting edge region (25) and the arcuate cutting edge region (24) are spaced apart from each other, the width of the linear cutting edge region (25) is set greater than the width of the intermediate surface region (18), and when the arcuate cutting edge portion (24) machines a predetermined groove portion (17), the linear cutting edge portion (25) is set to be capable of machining another intermediate surface portion (18) located adjacent to the intermediate surface portion (18) located adjacent to the predetermined groove portion (17). [3] A method for manufacturing a piston (1) for machining an outer surface (11) of a skirt portion (10) of a piston (1) which slides and reciprocates along an inner wall surface of a cylinder bore of an engine by a turning tool (20) installed in a lathe, characterized by , that a cutting edge portion (23) of the turning tool (20) installed in the lathe includes an arcuate cutting edge portion (24) protruding toward the outer surface (11); and a linear cutting edge portion (25) disposed adjacent to the arcuate cutting edge portion (24) such that the linear cutting edge portion (25) is located at a front side in a tool feed direction relative to a hole center of a mounting hole (22) and extends parallel to the tool feed direction, the method for producing a piston (1) simultaneously a machining step for a groove portion (17) for machining a plurality of groove portions (17) which are spaced apart from each other in a direction parallel to the tool feed direction on the outer surface (11) and which extend in a circumferential direction through the arcuate cutting edge portion (24), and an intermediate surface region machining step (18) for machining an intermediate surface region (18) located between the mutually adjacent groove regions (17) and extending in a direction parallel to the tool feed direction through the linear cutting edge region (25), wherein the tool feed direction is a direction from the arcuate cutting edge region (24) towards the linear cutting edge region (25). [4] A method for manufacturing a piston (1) according to claim 3, comprising a finishing step following the machining step for a groove portion (17) and the machining step for an intermediate surface portion (18), wherein the finishing step of turning the intermediate surface portion (18) by the arcuate cutting edge portion (24) is performed at a cutting depth smaller than the cutting depth in the machining step for a groove portion (17) and in the machining step for an intermediate surface portion (18). [5] Piston (1) having an outer surface (11) of a skirt portion (10) adapted to slide along an inner wall surface of a cylinder bore of an engine, wherein the outer surface (11) includes low surface pressure receiving areas (A1, A3) and a high surface pressure receiving area (A2), with a plurality of groove portions (17) extending in a circumferential direction and spaced apart from each other in an axial direction; and with an intermediate surface portion (18) extending in the axial direction between the mutually adjacent groove portions (17) in the axial direction, and a depth of the groove portion (17) located in the high surface pressure receiving area (A2) on the outer surface (11) is greater than the depth of the groove portion (17) located at the low surface pressure receiving areas (A1, A3) in the axial direction of the outer surface (11), and the width in the axial direction of the intermediate surface portion (18) located in the high surface pressure receiving area (A2) is greater than the width in the axial direction of the intermediate surface portion (18) located in the low surface area receiving areas (A1, A3).

Images