| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce abrasion between a wall surface and a pinion gear by forming a plurality of tracks having a larger hardness level than a hardness level of an adjacent part, on a pocket wall surface for supporting the pinion gear of a drum. SOLUTION: A differential device case 40 has a drum 50 provided with a radial direction flange 50a having an aligned installing hole 54. The drum 50 has a plurality of axial direction holes which are communicated with each other and which are communicated with a center chamber 62, namely, has gear pockets 64, 66. The gear pockets 64, 66 are arranged in a circumferential direction in parallel with a rotary axis of a case 40 with set. For reducing abrasion between teeth of a pinion gear and a wall surface corresponding to the gear pockets 64, 66, a plurality of hardening tracks 80 are formed in the gear pockets 64, 66. The hardening tracks 80 extend in parallel with each other in a longitudinal direction for instance.</p> |
