The invention relates to a variable hydrostatic guideway for vertical lathes that includes a plurality of sectors (4) arranged between the periphery (1b) and a central opening (1a) of an annular base (1), each sector (4) including an upper housing (4a) having an outlet for hydraulic fluid (4b) such that, when the injected hydraulic fluid overflows from the housings (4a), it forms a film between a rotating plate (3) and the sectors (4); a positioning mechanism that includes a plurality of hydraulic cylinders (5) attached radially to the annular base (1) between the central opening (1a) and the sectors (4), the rod of each hydraulic cylinder (5) being connected to a piston (5j) and to one of the sectors (4); each sector (4) is guided in a radial guidance element (6) such that, by the action of the hydraulic cylinder (5), the sector (4) can move between an inside radial position and an outside radial position.
B23Q 1/38 - Movable or adjustable work or tool supports characterised by constructional features relating to the co-operation of relatively movable membersMeans for preventing relative movement of such members using fluid bearings or fluid cushion supports
B23Q 1/52 - Movable or adjustable work or tool supports using particular mechanisms with rotating pairs only a single rotating pair
F16C 32/06 - Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
2.
MACHINE AND METHOD FOR MACHINING LARGE CRANKSHAFTS
The invention relates to a machine and method for machining large crankshafts, enabling the simple and reliable synchronisation of the rotational movement of the crankshaft (14) at all of the points thereof. The machine includes: a machining tool (1) configured to move along the length of at least one guide (2) between a first end supporting element (3) and a second end supporting element (4), an electronic angular position sensor (6) located on a first rotation shaft (7) of the first end supporting element (3), and a second electronic angular position sensor (8) located on a second rotation shaft (9) of the second end supporting element (4), such that the rotational movement of the first end supporting element (3) is electronically synchronised with the rotational movement of the second end supporting element (4) at all times during the machining of the crankshaft (14).
B23B 5/18 - Turning-machines or devices specially adapted for particular workAccessories specially adapted therefor for turning crankshafts, eccentrics, or cams, e.g. crankpin lathes
B23Q 15/22 - Control or regulation of position of tool or workpiece
G05B 19/18 - Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
3.
SUPPORTING ELEMENT AND MACHINE FOR MACHINING LARGE CRANKSHAFTS
The invention relates to a supporting element and a machine for machining large crankshafts, enabling the anchoring of a crankshaft (1) to be machined and the transmission of a torque thereto using a rotation shaft (2). The invention includes zero-clearance rotation transmission means comprising at least a first endless screw (3) and at least a second endless screw (4) which are functionally connected to a crown wheel (5) configured to transmit torque to the crankshaft (1). According to the invention, the first endless screw (3) is functionally connected to the second endless screw (4) and the connection area between the first endless screw (3) and the crown wheel (5) is different from the connection area between the second endless screw (4) and the crown wheel (5).
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