Metal deforming – By use of tool acting during relative rotation between tool... – During rotation of work
Reexamination Certificate
1999-09-20
2001-06-26
Crane, Daniel C. (Department: 3725)
Metal deforming
By use of tool acting during relative rotation between tool...
During rotation of work
C072S469000
Reexamination Certificate
active
06250123
ABSTRACT:
TECHNICAL FIELD
This invention relates to a power transmission member having opposed spline ends at an annular groove such as for holding a snap ring, and the invention also relates to a method, apparatus and a rack for splining the power transmission member.
BACKGROUND ART
Snap ring grooves have previously been formed in splined power transmission members by material removal such as grinding. Furthermore, U.S. Pat. Nos. 4,644,772 Killop et al. and 4,689,980 Killop et al. disclose toothed racks that have elongated blade members with a progressively increasing height for deforming a workpiece to form the entirety of an annular groove with a uniform cross-section. Such forming necessarily exerts significant pressure on the elongated blade members and results in wear that can require early replacement of the associated toothed racks.
DISCLOSURE OF INVENTION
An object of the present invention is to provide an improved method for rolling splines having opposed ends that are spaced from each other at an annular groove in a workpiece whose processing provides the previously described power transmission member.
In carrying out the above object, the method for rolling splines in accordance with the invention is performed by rotatably supporting about a rotational axis a workpiece having an annular groove with an annular root surface and with side walls that are spaced from each other. The workpiece is engaged on opposite sides with a pair of racks that are moved in opposite directions as each other and that have teeth for rolling the splines in the workpiece and with each rack having an elongated die that is received within the annular groove in the workpiece and that has side surfaces spaced from each other slightly less than the spacing between the side walls of the annular groove such that spline ends are formed against the side surfaces of the elongated dies in an opposed and precisely located relationship at the outer extremity of the annular groove in the workpiece and with the side walls of the annular groove inwardly from the spline ends being spaced slightly farther from each other than the spacing of the spline ends from each other.
In the preferred practice of the method, the workpiece is initially allowed to axially float along the rotational axis to facilitate alignment of the elongated dies of the racks with the annular groove of the workpiece, and the workpiece is subsequently axially fixed along the rotational axis during the spline rolling.
The preferred practice of the method for spline rolling a workpiece also has a tip of each elongated die engaged with the annular root surface of the annular groove during the spline rolling to provide work hardening thereof that provides strengthening.
The rotational support of the workpiece during the spline rolling is between headstock and tailstock centers which are initially positioned to allow the workpiece to axially float along the rotational axis and are subsequently provided with relative axial movement toward each other to axially fix the workpiece along the rotational axis during the spline rolling and forming of the spline ends at the annular groove in the workpiece.
Another object of the present invention is to provide improved apparatus for rolling splines having opposed ends that are spaced from each other at an annular groove in a workpiece.
In carrying out the immediately preceding object, headstock and tailstock centers rotatably support about a rotational axis a workpiece having an annular groove with an annular root surface and with side walls spaced from each other. A pair of racks of the apparatus are moved in opposite directions as each other and have teeth for rolling splines in the workpiece. Each rack has an elongated die that is received within the annular groove as the splines are rolled. Each elongated die has side surfaces spaced from each other slightly less than the spacing between the side walls of the annular groove such that spline ends are formed against the side surfaces of the elongated dies in an opposed and precisely located relationship at the outer extremity of the annular groove in the workpiece and with the side walls of the annular groove inwardly from the spline ends being spaced slightly farther from each other than the spacing of the spline ends from each other.
Headstock and tailstock positioners initially position the headstock and tailstock centers to allow the workpiece to axially float along the rotational axis to facilitate initial alignment movement of leading ends of the elongated dies into the annular groove of the workpiece. The headstock and tailstock positioners subsequently provide relative movement between the headstock and tailstock centers toward each other to axially fix the workpiece along the rotational axis as the spline rolling is performed. The elongated dies may have tips that engage the annular root surface of the annular groove during the spline rolling to provide work hardening that provides strengthening.
Another object of the present invention is to provide an improved rack for rolling splines having opposed ends that are spaced from each other at an annular groove in a workpiece.
In carrying out the immediately preceding object, the spline rolling rack according ion includes teeth for rolling the splines in the workpiece on opposite sides which has an annular root surface and side walls spaced from each other. An elongated die of the rack is received within the annular groove as the splines are rolled. The elongated die has side surfaces that are spaced from each other slightly less than the spacing between the side walls of the annular groove such that spline ends are formed against the side surfaces of the elongated dies in an opposed and precisely located relationship at the outer extremity of the annular groove in the workpiece and with the side walls of the annular groove inwardly from the spline ends being spaced slightly farther from each other than the spacing of the spline ends from each other. The elongated die has leading and trailing ends and has a flat tip that extends between the side surfaces in a perpendicular relationship to the side surfaces for the entire extent between the leading and trailing ends.
In the preferred construction of the rack, the elongated die has a tapered leading end that projects forwardly from the teeth to provide the initial alignment of the workpiece and the elongated die of the rack.
In its preferred construction, the rack includes a pair of elongated rack portions each of which has spaced tooth portions. The elongated die of the rack includes an elongated die member positioned between the pair of elongated rack portions and projecting therefrom so as to be received within the annular groove in the workpiece during the spline rolling. A connection of the rack secures the pair of elongated rack portions to each other with the elongated die member therebetween in a secured relationship.
In the preferred construction of the rack, the elongated die has a tip that engages the annular root surface of the annular groove to provide work hardening that provides strengthening.
REFERENCES:
patent: 446932 (1891-02-01), Simonds
patent: 4644772 (1987-02-01), Killop et al.
patent: 4689980 (1987-09-01), Killop et al.
patent: 348504 (1982-08-01), None
Brooks & Kushman P.C.
Crane Daniel C.
Utica Enterprises Inc.
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