Abstract: A gear is configured such that: a ring gear, a drive pinion shaft having a pinion gear meshing with the ring gear, and rolling bearings supporting the drive pinion shaft such that the drive pinion shaft is rotatable are accommodated in a differential housing; the differential housing is divided into a differential mechanism chamber in which to accommodate the ring gear, and a pinion shaft chamber in which to accommodate the rolling bearings; and a feed oil passage configured to supply lubricant scooped up by the ring gear to the pinion shaft chamber, and a return oil passage configured to discharge the lubricant in the pinion shaft chamber to the differential mechanism chamber are provided in the differential housing. In the differential gear, an inlet of the feed oil passage is placed at a position that is offset from the ring gear in an axial direction of the ring gear.

Abstract: A differential housing is configured to support a plurality of bearings. The differential housing includes a first bearing surrounding member provided to surround a first bearing included in the plurality of bearings. The differential housing includes a second bearing surrounding member provided to surround a second bearing included in the plurality of bearings; and a connecting member that connects the first bearing surrounding member and the second bearing surrounding member, at least a part of the connecting member being embedded in a wall that is made of a base material of the differential housing. Each of the first bearing surrounding member, the second bearing surrounding member, and the connecting member is constructed of a material having a smaller linear expansion coefficient than that of the base material of the differential housing.

Abstract: A vehicle differential includes a pair of side gears, a pinion gear, a differential case, and an annular ring gear. The differential case includes an opening penetrating a peripheral wall of the differential case. The annular ring gear is attached to an outer side of the peripheral wall of the differential case such that a central axis of the annular ring gear and a rotational axis of the differential case coincide with each other. The annular ring gear includes a protrusion on an inner peripheral edge of the annular ring gear. The protrusion covers a part of the opening when viewed in a penetration direction of the opening. The protrusion protrudes toward the inner side of the opening in the radial direction of the rotational axis as compared with an other part of the inner peripheral edge of the annular ring gear that has no protrusion.

Abstract: A differential housing is configured to support a plurality of bearings. The differential housing includes a first bearing surrounding member provided to surround a first bearing included in the plurality of bearings. The differential housing includes a second bearing surrounding member provided to surround a second bearing included in the plurality of bearings; and a connecting member that connects the first bearing surrounding member and the second bearing surrounding member, at least a part of the connecting member being embedded in a wall that is made of a base material of the differential housing. Each of the first bearing surrounding member, the second bearing surrounding member, and the connecting member is constructed of a material having a smaller linear expansion coefficient than that of the base material of the differential housing.

Abstract: A rotation state of each rotating element of a four-wheel drive vehicle and an operating state of each engagement element of a disconnect mechanism, corresponding to an operating state of the disconnect mechanism, are displayed on or near a vehicle model image on a vehicle display. Thus, it is possible to inform a driver of the operating state of the disconnect mechanism at any time. Thus, the driver is able to recognize the operating state of the disconnect mechanism at any time, so the driver is able to carry out driving based on the operating state.

Abstract: A gear is configured such that: a ring gear, a drive pinion shaft having a pinion gear meshing with the ring gear, and rolling bearings supporting the drive pinion shaft such that the drive pinion shaft is rotatable are accommodated in a differential housing; the differential housing is divided into a differential mechanism chamber in which to accommodate the ring gear, and a pinion shaft chamber in which to accommodate the rolling bearings; and a feed oil passage configured to supply lubricant scooped up by the ring gear to the pinion shaft chamber, and a return oil passage configured to discharge the lubricant in the pinion shaft chamber to the differential mechanism chamber are provided in the differential housing. In the differential gear, an inlet of the feed oil passage is placed at a position that is offset from the ring gear in an axial direction of the ring gear.

Abstract: A vehicle differential includes a pair of side gears, a pinion gear, a differential case, and an annular ring gear. The differential case includes an opening penetrating a peripheral wall of the differential case. The annular ring gear is attached to an outer side of the peripheral wall of the differential case such that a central axis of the annular ring gear and a rotational axis of the differential case coincide with each other. The annular ring gear includes a protrusion on an inner peripheral edge of the annular ring gear. The protrusion covers a part of the opening when viewed in a penetration direction of the opening. The protrusion protrudes toward the inner side of the opening in the radial direction of the rotational axis as compared with an other part of the inner peripheral edge of the annular ring gear that has no protrusion.

Abstract: A rotation state of each rotating element of a four-wheel drive vehicle and an operating state of each engagement element of a disconnect mechanism, corresponding to an operating state of the disconnect mechanism, are displayed on or near a vehicle model image on a vehicle display. Thus, it is possible to inform a driver of the operating state of the disconnect mechanism at any time. Thus, the driver is able to recognize the operating state of the disconnect mechanism at any time, so the driver is able to carry out driving based on the operating state.

Abstract: A shaft device which can ensure satisfactory lubrication for a shaft is provided. The shaft device includes a casing having a first insertion hole receiving a pin in a direction transverse to an axial direction. The shaft has a second insertion hole receiving the pin in a direction transverse to the axial direction. The pin is disposed through both the first insertion hole and the second insertion hole to fix the shaft to the casing relatively. The casing further has a space permitting the shaft to rotate in its circumferential direction with the pin partially inserted in the second insertion hole.

Abstract: A differential gear is structured such that a first differential case and a second differential case overlap one another in the radial direction such that a first joining portion of the first differential case, i.e., a portion of an outward flange that is on the outer peripheral side of a through-hole, is positioned on the outer peripheral side of a second joining portion of the second differential case, i.e., a joining protrusion that is inserted in the through-hole. In addition, the ring gear is arranged facing those joining portions in the direction of the axis, and laser beam welded from the outer peripheral side at the portion where the ring gear faces both of those joining portions. Accordingly, the three members, i.e., the first differential case, the second differential case, and the ring gear, are all integrally joined together by a single welding operation, and manufacturing costs can be reduced.

Abstract: A shaft device which can ensure satisfactory lubrication for a shaft is provided. The shaft device includes a casing having a first insertion hole receiving a pin in a direction transverse to an axial direction. The shaft has a second insertion hole receiving the pin in a direction transverse to the axial direction. The pin is disposed through both the first insertion hole and the second insertion hole to fix the shaft to the casing relatively. The casing further has a space permitting the shaft to rotate in its circumferential direction with the pin partially inserted in the second insertion hole.

Abstract: The multiple meshing teeth of a hypoid gear multiple are cut at a specified spiral angle. The pressure angle on a tooth convex surface (16a) of a ring gear (12) and on a tooth concave surface (18b) of the pinion (14), which contacts the tooth convex surface (16a), increases from a small diameter end toward a large diameter end. Accordingly, contact ratio between the tooth convex surface (16a) and the tooth concave surface (18b) may be increased. Furthermore, the pressure angle on a tooth concave surface (16b) of the ring gear (12) and on a tooth convex surface (18a) of the pinion (14), which contacts the concave tooth surface (16b), continuously decreases from the small diameter end toward the large diameter end. Accordingly, the contact ratio between the tooth concave surface (16b) and the tooth convex surface (18a) can be increased.

Abstract: A differential gear is structured such that a first differential case and a second differential case overlap one another in the radial direction such that a first joining portion of the first differential case, i.e., a portion of an outward flange that is on the outer peripheral side of a through-hole, is positioned on the outer peripheral side of a second joining portion of the second differential case, i.e., a joining protrusion that is inserted in the through-hole. In addition, the ring gear is arranged facing those joining portions in the direction of the axis, and laser beam welded from the outer peripheral side at the portion where the ring gear faces both of those joining portions. Accordingly, the three members, i.e., the first differential case, the second differential case, and the ring gear, are all integrally joined together by a single welding operation, and manufacturing costs can be reduced.