Method and machine tool for a circular machining of eccentric shaft portions
AssigneeGFM Gesellschaft fur Fertigungstechnik und Maschinenbau Gesellschaft m.b.H.
InventorGottfried Blaimschein
Life of this patent
Estimating the term…
Abstract
When it is desired to machine crankpins of crankshafts to a circular cross section with a surrounding cutting tool, which is rotated or oscillated, the tool is longitudinally positioned relative to the crankpin and machines the same while engaging the crankpin and a circular feed movement of the tool relative to the crankpin is effected. To permit a fast and efficient circular machining, the crankpin is held in position and the driven tool is moved during the machining along a circular path surrounding the crankpin. When the tool has been longitudinally positioned, the crankpin and the tool are transversely displaced relative to each other until the center of the circular cross section coincides with the center of the circular path of the tool.
Claims18
In a method of machining a shaft workpiece with an externally cutting tool to form said shaft workpiece with an eccentric portion having a predetermined circular cross-section, comprising the steps of
- moving said tool relative to said shaft workpiece in the longitudinal direction of the latter to position said tool adjacent to a predetermined portion of said shaft workpiece,
- moving said tool transversely to the longitudinal direction of said shaft workpiece to engage said tool with said shaft workpiece, and
- machining said predetermined portion of said shaft workpiece with said tool while imparting to said tool and said shaft workpiece a feed movement relative to each other whereby said tool is moved around said shaft workpiece along a predetermined circular path,
- the improvement residing in that
- after said tool has thus been positioned, said tool and said predetermined portion of said shaft workpiece are moved relative to each other in a direction which is transverse to said longitudinal direction to a position in which the center of said predetermined cross-section of said eccentric portion coincides with the center of said circular path,
- said tool is subsequently moved to engage said predetermined portion of said shaft workpiece,
- said tool which engages said predetermined portion of said shaft workpiece is driven to machine said predetermined portion of said shaft workpiece,
- said shaft workpiece is held in position as it is machined by said tool, and
- said tool is moved around said shaft workpiece along said circular path as said predetermined portion of said shaft workpiece is machined by said tool.
In a machine tool for machining a shaft workpiece to form it with an eccentric portion having a predetermined circular cross-section, comprising
- an externally cutting tool for machining said shaft workpiece to form it with said eccentric portion,
- two spaced apart gripping means defining a longitudinal axis and operable to grip said workpiece so that it extends along and is centered on said longitudinal axis,
- first tool-positioning means for moving said tool relative to said gripping means along said longitudinal axis to position said tool adjacent to a predetermined portion of a shaft workpiece gripped by said gripping heads,
- second tool-positioning means for moving said tool relative to said gripping heads transversely to said longitudinal axis to engage said tool with said predetermined portion of said shaft workpiece gripped by said gripping means,
- a feed drive for imparting to said tool and said gripping means a feed movement relative to each other whereby said tool is moved around said longitudinal axis along a circular path while said tool engages said predetermined portion of said shaft workpiece gripped by said gripping means, and
- tool-driving means for imparting to said tool a cutting movement when said tool is engaged with said predetermined portion of said shaft workpiece gripped by said gripping heads and is moved around said longitudinal axis along said circular path,
- the improvement residing in that
- said gripping heads are operable to hold said shaft workpiece in position,
- third tool-positioning means are provided, which are operable to move said tool and said gripping means relative to each other in a direction which is transverse to said longitudinal axis to a position in which the center of said predetermined cross-section of said eccentric portion coincides with the center of said circular path,
- said second tool-positioning means are connected to said tool and operable to move said tool into engagement with said predetermined portion of said workpiece when the center of said predetermined cross-section of said eccentric portion coincides with the center of said circular path, and
- said feed drive is connected to said tool and operable to move said tool along said circular path.
Dependencies are inferred from the claim text.