| 摘要 |
<p>A clamping device (10) in a main shaft driving device (1) for a machine tool is provided. The main shaft driving device (1) rotationally drives a main shaft (4a) by a driving device (6, 9). The main shaft (4a) is rotatably supported by a frame (2) and has a member that is rotationally driven (5) secured to an end portion thereof. The clamping device (10) includes a braking member (44, 64), a pressure chamber (36a, 36b, 49a, 49b), and an operating fluid supplying mechanism (42), the braking member (44, 64) provided at a side of the frame (2) and including a pressure-receiving surface (35a, 35b) and a braking portion (31a, 31b, 44c), the pressure-receiving surface (35a, 35b) receiving pressure of an operating fluid, the braking portion (31a, 31b, 44c) causing a press-contact force to act upon the main shaft (4a), the pressure chamber (36a, 36b, 49a, 49b) being formed by the pressure-receiving surface (35a, 35b) and the frame (2), the operating fluid supplying mechanism (42) being provided for supplying the operating fluid from an operating fluid supply source to the pressure chamber (36a, 36b, 49a, 49b), wherein the press-contact force is caused to act upon the main shaft (4a) by displacing the braking portion (31a, 31b, 44c) towards the main shaft (4a) by the pressure of the operating fluid that is supplied to the pressure chamber (36a, 36b, 49a, 49b). The clamping device (10) is such that the braking member (44, 64) has a first pressure-receiving surface (35a) and a second pressure-receiving surface (35b), which extend orthogonally to a direction in which the braking portion (31a, 31b, 44c) causes press-contact forces to act upon the main shaft (4a); the operating fluid supplying mechanism (42) includes a switching portion (48) that selectively supplies the operating fluid from a common operating fluid supply source to at least one of first and second pressure chambers (36a, 36b, 49a, 49b), the first pressure chamber (36a, 49a) being formed by the first pressure-receiving surface (35a) and the frame (2), the second pressure chamber (36b, 49b) being formed by the second pressure-receiving surface (35b) and the frame (2); and the braking member (44, 64) is formed so that the braking portion (31a, 31b, 44c) causes the press-contact forces that differ from each other to act upon the main shaft (4a) when pressures that are equal to each other act upon the first pressure-receiving surface (35a) and second pressure-receiving surface (35b), respectively.</p> |
