Coupler yoke and coupler draft gear

A coupler yoke, comprising a hollow yoke body with a cross section being in a long concentric-square shape, wherein an inner side surface of one end of the hollow yoke body is a bearing surface used for bearing a load, wherein

• the bearing surface comprises a heavy loading area and a light loading area, the heavy loading area bears a load with larger strength compared with the light loading area, wherein the light loading area is located in a middle area and an edge area of the bearing surface, the heavy loading area is located between the middle area and the edge area of the bearing surface, and at least one part of the heavy loading area protrudes outwards relatively to an end surface of the light loading area,
• wherein the middle area comprises a transverse stripe area and a longitudinal stripe area, the transverse stripe area is distributed along a width center line of the bearing surface towards two sides of the width center line, and the longitudinal stripe area is distributed along a length center line of the bearing surface towards two sides of the length center line;
• and the edge area comprises an upper edge area, a lower edge area, a left edge area and a right edge area of the bearing surface,
• the bearing surface is in an integrated structure, the light loading area comprises the upper edge area, the lower edge area, the left edge area and the right edge area, the transverse stripe area and the longitudinal stripe area of the bearing surface, the light loading area is in a “” shape, the left edge area and the right edge area of the bearing surface are respectively provided with the inclined surfaces, grooves are respectively arranged in the longitudinal stripe area, transverse stripe area, upper edge area and lower edge area of the light loading area, wherein the grooves in the upper edge area and the transverse stripe area as well as the inclined surfaces between the two grooves are connected end to end to form an upper annular concave stripe, the grooves in the lower edge area and the transverse stripe area as well as the inclined surfaces between the two grooves are connected end to end to form a lower annular concave stripe, and the grooves in the longitudinal stripe area runs through the upper annular concave stripe and the lower annular concave stripe, so that the upper annular concave stripe is divided into an upper left annular concave stripe and an upper right annular concave stripe, and the lower annular concave stripe is divided into a lower left annular concave stripe and a lower right annular concave stripe;
• and the heavy loading area is formed on the bearing surface encircled by the upper left annular concave stripe, the upper right annular concave stripe, the lower left annular concave stripe and the lower right annular concave stripe, and the heavy loading area protrudes outwards relatively to the end surface of the light loading area.