US 3,964,367 A · Device for machining trochoidal inner walls, especially for the cylinders of Wankel engines

Abstract

A machine for machining the inner walls of the cylinder of a Wankel engine in which a support is provided for the cylinder to be machined which rotates the cylinder about a first axis in one direction with the first axis moving bodily about a second axis in the opposite direction. Cutting tools are provided which engage the inside of the wall of a cylinder mounted on the support and effect cutting thereof during movement of the cylinder. The tools are mounted on support elements which are pivotal about lines substantially coinciding with the lines of engagement of the respective tools with the cylinder wall of the cylinder and are pivoted during movement of the cylinder to maintain substantially the same cutting conditions between each tool and the cylinder.

Claims20

Dependent claims

A machine for machining the inner wall of a cylinder for a Wankel engine in which the cylinder moves about rotary cutting tool means in a substantially trochoidal path, said machine comprising:

a workpiece support for said cylinder, at least two cutting tools, pivoted arms supporting the cutting tools in spaced relation with each arm supported on its respective pivot, bearing means for rotatably supporting said workpiece support about a first axis, a rotatable member supporting said bearing means for rotation about a second axis spaced from said first axis while the workpiece support rotates in the opposite direction on said bearing means, a single control element engaging said arms for pivotal movement and means driving said rotatable member and said control element simultaneously to move said arms about their respective pivots to maintain substantially constant the angle between a first plane passing through the center of rotation of each tool and the pivotal axis of its respective pivoted arm and a second plane tangent to an arcuate portion of the inner wall of the workpiece at the line of contact of the respective tool therewith.

An apparatus for machining a substantially trochoidal surface on the wall of a cavity in a workpiece, said apparatus comprising:

a workpiece support table adapted to support a workpiece to be machined, bearing means supporting said table for rotation on an axis parallel to the axis of the cavity in a workpiece thereon, a crank arm supporting said bearing means for bodily rotation thereof in parallelism with itself in one direction and means for simultaneously rotating said table on said bearing means in the opposite direction whereby a point on the inner wall of the workpiece follows a trochoidal path, cutting tools equal in number to at least one more than the number of lobes in the trochoidal surface being machined and rotatable on axes parallel to the axis of said cavity and disposed in circumferentially distributed relation adjacent the wall of the cavity of a workpiece on said table, a lever supporting each said tool, a stationary pivot element rotatably supporting each said lever on an axis parallel to the axis of the cavity, control means engaging said levers in a region spaced from the respective said pivot elements and movable for causing said levers to pivot simultaneously on said pivot elements and thereby move said tools, and means for actuating said control means in synchronism with the movement of said table to cause pivotal movement of said levers to maintain the planes containing the axes of rotation of the respective tools and the pivot axes of the levers perpendicular to the respective planes tangent to the arcuate surface at the lines of contact of the tools with the surface on the workpiece being machined.

Dependencies are inferred from the claim text.

Device for machining trochoidal inner walls, especially for the cylinders of Wankel engines

Life of this patent

Device for machining trochoidal inner walls, especially for the cylinders of Wankel engines

Life of this patent

Abstract

Claims20