GB1129389A - Method and apparatus for electromechanical honing - Google Patents

Abstract

1,129,389. Honing. MICROMATIC HONE CORP. 25 April, 1966 [20 Oct., 1965], No. 17993/66. Heading B3D. [Also in Division C7] A honing apparatus for removing metal by mechanical action and electrolytic action from the surface of a workpiece as anode comprises a tool including an electrically conductive cathode body, means for flowing an electrolyte between the work surface and the body, means for passing current from the work surface to the body through the electrolyte, an abrasive member mounted in the body and engageable with the work surface, means for moving the body and the abrasive member with respect to the work surface to remove metal electrolytically and mechanically from the work surface, and means for moving the abrasive member with respect to the body and with respect to the work surface. Typically the apparatus is adapted for finishing a cylindrical surface, e.g. the cylindrical bore in a gear-wheel and the cathode tool body has a cylindrical surface supporting angularly spaced radially extending and movable abrasive honing members or stones which may be electrically insulating or conducting, and cathodically connected gauging arms bearing non-conductive spacing elements, e.g. of diamond or ceramic are urged into contact with the work surface, the tool being both reciprocated and rotated. Preferably in use the supply of current is interrupted after a chosen time arid a final mechanical honing is effected. As shown, a carriage of spindle head assembly 12 is movable vertically on guides 31, 32 under control of a pneumatic or hydraulic system including a reversing valve operated by trips adjustably mounted on the carriage. The carriage rotatably supports a spindle 13 driven by a gear engaging a gear on a splined shaft supported independently of the carriage and driven by an electric motor. Cathodic connection is made to the spindle 13 by a brush assembly 208 and a cathode tool 14 is detachably secured to the spindle. The tool extends into a workpiece enclosure 15, e.g. of transparent plastic, with a sliding door, a bellows connection being provided between a sleeve 211 on the carriage 12 and the top of the enclosure 15. Electrolyte, e.g. sodium chloride solution which may be heated or cooled, is supplied to the working gap via ports 398 in the body 386 fed through communicating passages in the tool and spindle 13 from a hose connected to a port in the sleeve 211, and is drained from the enclosure 15 by a hose back into an electrolyte reservoir. If desired the ports 398 may be inclined downwardly. Air pressure in the spindle head assembly enclosure is maintained above that in the enclosure 15 to prevent electrolyte spray and splash. The workpiece 16 shown as a gear is located on a support plate 220 by two pinions which may be driven via a worm drive from an electric motor beneath the plate. Typically as shown, the tool 14 is provided with three each of electrolytic ports 398 honing stones 399 and gauging shoes 414. The honing stones which may be of bonded abrasive particles supported in a plastic are urged outwardly by the cam. ming action of a rod 390 (Fig. 19, not shown) slidably within the tool when this is attached to the spindle 13 and air is fed under pressure through the tool, while the gauging shoes with diamond points 416 are carried by pivoted arms urged outwardly by springs (see Fig. 19). A pneumatic sensing system employing channels formed in the spindle and tool detects the extent of movement of the arms and hence of the shoes and is adapted to stop operation of the tool. In an alternative mode of operation the honing operation is performed for a selected fixed time. Instead of being rigidly connected to the spindle the tool may have a floating connection. Modifications of the mounting of the gauging arms and for detecting their positions are described with reference to Figs. 24 to 28, 29 to 33, 42 to 45. In a further tool modification, the electrolyte is supplied to the working area via the gauging shoes and porous honing stones (Fig. 55, not shown). As an alternative electrolyte may be supplied to the working area through the workpiece support (Fig. 56, not shown). A pneumatic detection system is also provided for determining when the stones are worn and require replacement.