Abstract: A dog clutch includes a gear (40) mounted on a power transmission shaft (30), first and second dog rings (10, 20), a fork (60), springs (65), and cam grooves (31). The cam grooves (31) each include a first slope surface (36) inclined from the axial direction toward the positive rotation direction as the first slope surface (36) approaches the gear (40) and a second parallel surface (37) parallel to the axial direction. The first dog ring (10) includes first cam protrusions (16) to be engaged with the respective first slope surfaces (36), and the second dog ring (20) includes second cam protrusions (26) to be engaged with the respective second parallel surfaces (37). This structure prevents the dog rings and the fork from coming into contact with each other, thereby avoiding generation of abrasion and increasing the transmission efficiency.

Abstract: A first dog ring and a second dog ring are biased toward each other by means of springs. When the first dog ring and the second dog ring are moved away from each other, bias force produced by the springs is applied to the second dog ring in a direction to draw the second dog ring toward the first dog ring. Accordingly, when the first dog ring is moved away from the second dog ring during shifting, the second dog ring is drawn toward the first dog ring under the bias force, and third engaging teeth of the second dog ring and meshing teeth of a first-speed gear are promptly disengaged from each other.

Abstract: A first dog ring and a second dog ring are biased toward each other by means of springs. When the first dog ring and the second dog ring are moved away from each other, bias force produced by the springs is applied to the second dog ring in a direction to draw the second dog ring toward the first dog ring. Accordingly, when the first dog ring is moved away from the second dog ring during shifting, the second dog ring is drawn toward the first dog ring under the bias force, and third engaging teeth of the second dog ring and meshing teeth of a first-speed gear are promptly disengaged from each other.

Abstract: A dog clutch includes a gear (40) mounted on a power transmission shaft (30), first and second dog rings (10, 20), a fork (60), springs (65), and cam grooves (31). The cam grooves (31) each include a first slope surface (36) inclined from the axial direction toward the positive rotation direction as the first slope surface (36) approaches the gear (40) and a second parallel surface (37) parallel to the axial direction. The first dog ring (10) includes first cam protrusions (16) to be engaged with the respective first slope surfaces (36), and the second dog ring (20) includes second cam protrusions (26) to be engaged with the respective second parallel surfaces (37). This structure prevents the dog rings and the fork from coming into contact with each other, thereby avoiding generation of abrasion and increasing the transmission efficiency.

Abstract: A first dog ring and a second dog ring are biased toward each other by means of springs. When the first dog ring and the second dog ring are moved away from each other, bias force produced by the springs is applied to the second dog ring in a direction to draw the second dog ring toward the first dog ring. Accordingly, when the first dog ring is moved away from the second dog ring during shifting, the second dog ring is drawn toward the first dog ring under the bias force, and third engaging teeth of the second dog ring and meshing teeth of a first-speed gear are promptly disengaged from each other.