An apparatus for machining a workpiece with a tool has a columnar housing having an upright front face and a pair of upright and parallel side walls extending horizontally rearward from the front face, a carriage movable at least vertically on the front face carries a first holder for the workpiece or the tool. A U-shaped frame juxtaposed with the housing front face has two rigid arms each extending rearward adjacent the housing side walls with interfitting guides between each of the arms and the respective side wall enabling horizontal movement of the frame toward and away from the front face. A second holder on the frame and in front of the front wall holds the tool or the workpiece and is engageable with the workpiece or the tool, respectively, in the first holder.

FIELD OF THE INVENTION

The present invention relates to a machining apparatus. More particularly this invention concerns such an apparatus with the ability to work along the Y-axis.

BACKGROUND OF THE INVENTION

A machining apparatus for machining rotationally driven workpieces with Y-axis movement are known in the prior art. US 2010/0202847 shows a machining apparatus having a vertical main spindle, tool turret, and a hobber. The machining units are mounted on the front vertical wall of the machine frame. The tool turret and the hobber can be moved vertically and horizontally on a compound slide. In addition, the hobbing spindle includes a swivel axis (B axis) and a shift axis, and can furthermore be moved in a third axis (Y axis). Guides in the direction of the Y axis are mounted in front of the vertical wall of the machine frame. This necessarily results in a relatively large distance between the rotation axes and the frame wall, which distance negatively affects the flow of power and machine rigidity.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide an improved y-axis machining apparatus.

Another object is the provision of such an improved y-axis machining apparatus that overcomes the above-given disadvantages, in particular that has a compact design and improved machine rigidity.

SUMMARY OF THE INVENTION

An apparatus for machining a workpiece with a tool has according to the invention a columnar housing having an upright front face and a pair of upright and parallel side walls extending horizontally rearward from the front face, a carriage movable at least vertically on the front face carries a first holder for the workpiece or the tool. A U-shaped frame is juxtaposed with the housing front face has two rigid arms each extending rearward adjacent the housing side walls with interfitting guides between each of the arms and the respective side wall enabling horizontal movement of the frame toward and away from the front face. A second holder on the frame and in front of the front wall holds the tool or the workpiece and is engageable with the workpiece or the tool, respectively, in the first holder.

Thus according to the invention, a U-shaped slide that is movable in the direction of the Y axis of the machine coordinate system is movably guided along guide rails on the two arms of the U-shaped frame on parallel mutually opposing side walls of the machine housing. In an especially advantageous approach, the driving forces for positioning the slide are introduced symmetrically through the two arms. A vertical slide for a motor spindle is mounted in the top section on the front wall of the machine housing.

This configuration enables a symmetrical flow of force to be achieved overall, and specifically also for the assemblies of the Y axis. This has an especially positive effect on the rigidity of the machine. The machining apparatus can also operate on the pick-up principle. A motor spindle with a clamping chuck for workpieces is movable horizontally (X axis) in suspended fashion. The motor spindle moves to a pick-up or placement position for loading and unloading. Rotary-driven tools for hobbing, grinding, milling, or honing are provided on the slide (Y axis).

The high degree of machine rigidity means that the machining apparatus is especially well suited for precision machining operations such as grinding or honing. However, it can also be advantageously used for precise hobbing operations. In the case of a hand-loaded machine, the workpiece spindle is mounted stationarily on the slide and can move in the Y axis, while the motor spindle can be moved in suspended fashion on the vertical slide from the machining position to the workpiece changing position in order to pick up tools.

DETAILED DESCRIPTION

As seen inFIGS. 1 and 2a machining apparatus1according to the invention has a square-section columnar housing2with a planar and vertical front wall3formed with a central hole32(FIG. 2) and a pair of parallel and vertical side walls19and19′ extending rearward perpendicularly from the front wall3. A pair of horizontally spaced and guide rails4extending parallel to a vertical Z-axis carry a cantilevered carriage plate5that can be moved vertically by a motor6fixed atop the housing2and connected via a ball spindle7to the carriage5to raise and lower it on the front wall3parallel to the Z-axis.

A holder or headstock9rides on vertically spaced rails8extending parallel to a horizontal X-axis and fixed to the front face of the carriage plate5. This carriage plate5is cantilevered laterally above a workpiece conveyor17that can move unmachined workpieces15into and out of a station12. These workpieces15can be picked up by a holder or chuck14carried by the headstock9and moved horizontally parallel to the X-axis into a machining station18located centrally in front of the front wall3between the rails4, and later finished workpieces15can be off by the chuck14in the station12and carried off. A motor13can rotate the chuck14and any workpiece15in it about a vertical axis36.

A massive U-shaped (seen from above) frame20has a pair of full-height arms29and29′ juxtaposed with the side walls19and19′ and each provided with shoes33riding on horizontal upper and lower rails21and21′ provided on the side walls19and19′. The rails21and21′ extend horizontally parallel to a Y-axis perpendicular to the X- and Z-axes. A pair of synchronous drives26and26′ are connected by ball spindles35and35′ (FIG. 2) to the arms29and29′ of the U-shaped frame20to move it horizontally forward and back, parallel to the Y-axis. Instead of the shoes33being on the frame20and the rails21and21′ on the housing2, the situation could be reversed with the rails21and21′ on the frame20and the shoes30on the housing2. The tool16engages one of the workpieces15in the machining station18as is well known in the art.

A support34is pivotal by a motor31(FIG. 2) in the housing cavity32perpendicular to the axis36on the planar and vertical front face3of the frame20about a horizontal axis27, the so-called C-axis, perpendicular to the face3and parallel to the Y-axis. This plate34acts as a holder carrying a tool16rotatable by a drive30about an axis37and also shiftable by the drive30in a direction28, the so-called B-axis, parallel to this axis37as is well known for hobbing.

The recessing of the motor31into the housing2, the nearly flush mounting of the plate support34on the frame20, and the large vertical spacing of the rails21and21′, impart considerably rigidity to the machining apparatus1and make it possible to position the tool16very accurately.

FIG. 3shows a hand-loaded version of the machine1where a workpiece holder22is fixed to the frame20and the holder9is used to hold one of the tools16to machine it, here shown drilling an axially centered hole in the held workpiece. To this end a turret24is provided in a tool station23carrying a plurality of tools16and located in the position of the loading/unloading station12ofFIGS. 1 and 2.