Abstract: A drive force distribution device for an automobile is provided in which a hydraulic clutch includes an annular oil groove opposing a clutch piston in an inner wall face of a clutch oil chamber, and a hydraulic oil supply port and a hydraulic oil discharge port communicating with the oil groove. Since when the hydraulic oil supply port of the oil groove is a starting end and the hydraulic oil discharge port of the oil groove is a finishing end, a cross-sectional area of a longer oil groove section of the annular oil groove is set to be larger than a cross-sectional area of a shorter oil groove section, the flow path resistance of the oil groove sect of the respective hydraulic clutches made to be uniform. This enables smooth operation, improvement of the engagement responsiveness and uniformization of the engagement responsiveness of the hydraulic clutches to be achieved.

Abstract: A drive force distribution device for an automobile is provided in which a hydraulic clutch includes an annular oil groove opposing a clutch piston in an inner all face of a clutch oil chamber, and a hydraulic oil supply port and a hydraulic oil discharge port communicating with the oil groove. Since when the hydraulic oil supply port of the oil groove is a starting end and the hydraulic oil discharge port of the oil groove is a finishing end, a cross-sectional area of a longer oil groove section of the annular oil groove is set to be larger than a cross-sectional area of a shorter oil groove section, the flow path resistance of the oil groove sect of the respective hydraulic clutches made to be uniform. This enables smooth operation, improvement of the engagement responsiveness and uniformization of the engagement responsiveness of the hydraulic clutches to be achieved.