Method and apparatus for grinding convergent conical surfaces

A method of simultaneously grinding two conical surfaces, one internal and the other external, converging at one end of an annular workpiece where they form a circular joining edge, comprising the steps of:

• mounting the workpiece on a rotary drive device;
• disposing in front of the end of the workpiece a first table displaceable towards said end of the workpiece in a direction defined by an angle .gamma., which may also be zero, relative to the axis of the workpiece;
• disposing on the first table a second table displaceable obliquely relative to the first table in a primary angular direction corresponding to the angle .alpha. of taper desired for one of the conical surfaces of the workpiece;
• fixing a rotatably mounted first grinding wheel spindle bearing a first conical or frustoconical grinding wheel, immovably to the second table so that the first grinding wheel spindle is displaced together with the second table in the primary angular direction;
• mounting a second grinding wheel spindle, bearing a second conical or frustoconical grinding wheel, on the second table in such a way that it is immovable relative to the second table in at least the direction perpendicular to the axis of the workpiece;
• providing the second grinding wheel spindle with means causing it to maintain the movement of the second grinding wheel face along a predetermined line positioned relative to the primary angular direction, which line corresponds to the angle .beta. of taper desired for the other of the conical surfaces of the workpiece;
• positioning a first grinding wheel truing tool associated with the first grinding wheel and a second grinding wheel truing tool associated with the second grinding wheel relative to the axis of the workpiece in a manner suitably determined for obtaining the desired diameter of the circular joining edge of the workpiece;
• setting the workpiece and the first and second grinding wheels in rotary motion;
• truing the first and second grinding wheels with the aid of the first and second grinding wheel truing tools at a first position, respectively;
• thereafter causing the second table to move obliquely in the primary angular direction to a second position to bring the first and second grinding wheels into simultaneous contact with said workpiece during grinding;
• and
• advancing the first table toward the workpiece and thereby causing the first and second grinding wheels to act simultaneously upon the end to be ground of the workpiece, the orientation of the advancing movement of the first table being such as to satisfy the equation
• (.alpha.-.beta.).multidot..gamma.=0,
• wherein .alpha. is the angle of taper corresponding to the primary angular direction, .beta. is the angle of taper corresponding to the predetermined line of movement of the second grinding wheel face, and .gamma. is the angle formed by the direction of displacement of the first table with the axis of the workpiece.

Apparatus for simultaneously grinding two conical surfaces, one internal and the other external, converging at one end of a workpiece where said surfaces form a circular joining edge, comprising:

• a first table displaceable in a direction defined by the angle of orientation of said first table relative to the axis of said workpiece;
• a second table mounted on said first table and displaceable obliquely relative to said first table in a primary angular direction corresponding to a first angle of taper desired for a first one of said conical surfaces;
• a first grinding-wheel spindle fixedly mounted on said second table for movement with said second table in said primary angular direction;
• a second grinding-wheel spindle mounted on said second table to be immovable relative to said second table in at least one direction;
• means for causing said second grinding-wheel spindle to move obliquely, in response to a displacement of said second table in said primary angular direction corresponding to a second angle of taper desired for a second one of said conical surfaces;
• a first grinding wheel mounted on said first grinding-wheel spindle;
• a second grinding wheel mounted on said second grinding-wheel spindle;
• a first and a second grinding-wheel truing tool respectively associated with said first and second grinding wheels and occupying, when in operation, respective positions relative to the axis of said workpiece determined as a function of said first and second angles of taper, respectively, the mutual relation between said positions being determined as a function of the desired diameter of said circular joining edge;
• and
• said first and second grinding wheels displaceable obliquely by movement of said second table from contact with said first and second truing tools into grinding contact with said workpiece.