Abstract: A power transmission device includes: a spindle case that includes a central hole through which an axle shaft penetrates in a central portion and forms a brake chamber in a region around the axle shaft at a base end portion; a wheel hub that is rotatably supported by an outer circumference of the spindle case and includes a final chamber, between the final chamber and the brake chamber, oil can flow, by communicating with the brake chamber through the central hole of the spindle case; a wet type brake mechanism that is contained in the brake chamber and operates so as to apply braking on rotation of the axle shaft with respect to the spindle case; and a deceleration mechanism that is contained in the final chamber and decelerates the rotation of the axle shaft to transmit the rotation to the wheel hub.

Abstract: A power transmission device includes: a spindle case that includes a central hole through which an axle shaft penetrates in a central portion and forms a brake chamber in a region around the axle shaft at a base end portion; a wheel hub that is rotatably supported by an outer circumference of the spindle case and includes a final chamber, between the final chamber and the brake chamber, oil can flow, by communicating with the brake chamber through the central hole of the spindle case; a wet type brake mechanism that is contained in the brake chamber and operates so as to apply braking on rotation of the axle shaft with respect to the spindle case; and a deceleration mechanism that is contained in the final chamber and decelerates the rotation of the axle shaft to transmit the rotation to the wheel hub.

Abstract: In an engine combustion chamber, a first intake port (19) formed from a straight port has a throat portion (43) formed in a linear shape and opening in a tangential direction of the inner periphery of a cylinder (11a), thus generating a first swirl (S1), and a second intake port (20) formed from a helical port has a throat portion (44) formed in a helical shape, thus generating a second swirl (S2) inside the first swirl (S1) in the same direction as that of the first swirl (S1). In this way, even with the first and second intake ports (19, 20) hardly curved overall, it is possible to efficiently generate first and second swirls (S1, S2) that do not interfere with each other, and it becomes possible to reduce the cost of machining the cylinder head, make the cylinder head compact, and simplify the structure of the cylinder head.

Abstract: In an engine combustion chamber, a first intake port (19) formed from a straight port has a throat portion (43) formed in a linear shape and opening in a tangential direction of the inner periphery of a cylinder (11a), thus generating a first swirl (S1), and a second intake port (20) formed from a helical port has a throat portion (44) formed in a helical shape, thus generating a second swirl (S2) inside the first swirl (S1) in the same direction as that of the first swirl (S1). In this way, even with the first and second intake ports (19, 20) hardly curved overall, it is possible to efficiently generate first and second swirls (S1, S2) that do not interfere with each other, and it becomes possible to reduce the cost of machining the cylinder head, make the cylinder head compact, and simplify the structure of the cylinder head.