WE CLAIM:
Claim 1. A boosting device (10) that includes a body (16, 26, 28, 38) having a supply port (96) and an output port (64) and that is configured to increase a pressure of a pressure fluid supplied from the supply port (96) and to output the boosted pressure fluid from the output port (64), the boosting device (10) comprising:
a driving source (18) that is provided in the body (16, 26, 28, 38) and that is rotationally driven under an action of energization;
a rotating body (30) coupled to a rotating shaft (24) of the driving source (18) and having a slope (68) that is inclined with respect to an axis line of the rotating shaft (24); and
a plurality of pistons (32a to 32d) disposed to be movable in an axial direction with respect to boosting chambers (48) in the body (16, 26, 28, 38) and each having an end that abuts on the slope (68),
wherein the plurality of pistons (32a to 32d) are sequentially urged in the axial direction by the slope (68) under an action of rotation of the rotating body (30), so as to compress and boost the pressure fluid in the boosting chambers (48).
Claim 2. The boosting device according to claim 1, wherein the plurality of pistons (32a to 32d) are arranged along a circumferential direction on a circumference about an axis line of the body (16, 26, 28, 38), and disposed inside an outer circumferential surface of the rotating body

(30) in a radial direction.
Claim 3 . The boosting device according to claim 1 or 2, wherein an end of each of the pistons (32a to 32d) that abuts on the rotating body (30) is formed substantially in a hemispherical shape.
Claim 4. The boosting device according to claim 1, wherein the boosting chambers (48) are each provided with a switching mechanism for establishing communication with the supply port (96) when the pressure fluid is supplied and establishing communication with the output port (64) when the pressure fluid is discharged.
Claim 5. The boosting device according to claim 4, wherein the switching mechanism includes:
a first switching valve (34) that opens only when the pressure fluid is supplied; and
a second switching valve (36) that opens only when the pressure fluid is discharged.
Claim 6. The boosting device according to claim 5, wherein each of the first and second switching valves (34, 36) rests and closes under a resilient action of a spring (88, 92), and opens under a pressing action by the pressure fluid.