Method and apparatus for inserting and removing a differential case cutter

Patent metadata

Field	Value
Publication number	US-10173266-B2
Application number	US-201715459601-A
Country	US
Kind code	B2
Filing date	Mar 15, 2017
Priority date	Mar 15, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A method and apparatus for machining an internal surface of a differential case. A lathe having a turret and a pair of spindles are in electrical communication with a programmable computer. Integrally connected to the turret is a cutter gripper assembly that is selectively grippingly engageable with a cutter. A differential case is mounted horizontally within a mount assembly on a tabletop of the lathe. Once the cutter gripping assembly engages the cutter, the turret moves toward the differential case until the cutter is in a start position within the hollow portion of the case aligned with openings in a first and second tubular portion of the case and the pair of spindles. The pair of spindles then drivingly engage the cutter and the cutter machines a first and second internal machining surface as the cutter moves from a first cutting position to a second cutting position.

First claim

What is claimed is:

1. A method of machining an internal surface of a differential case, comprising the steps of:
providing a lathe comprising a tabletop, a programmable computer, a lathe turret, a first spindle and a second spindle, wherein said lathe turret, said first spindle and said second spindle are in communication with said programmable computer;
providing a cutter gripping assembly comprising a pair of scissor arms that are integrally connected to a pair of cutter grippers;
attaching said cutter gripping assembly to said lathe turret;
providing a differential case comprising a hollow portion, a first tubular portion on a first end portion of said differential case, a second tubular portion on a second end portion of said differential case, one or more cross-pin openings in an intermediate portion of said differential case and one or more differential case windows in said intermediate portion of said differential case, wherein said first and second tubular portions are aligned with one another;
providing a mount assembly comprising a first cradle, a locator-pin, a second cradle, a first clamping arm and a second clamping arm that are integrally connected to said tabletop of said lathe;
mounting said differential case horizontally within said mount assembly, wherein said first cradle and said first clamping arm are in direct contact with said first tubular portion of said differential case, wherein said second cradle and said second clamping arm are in direct contact with said second tubular portion of said differential case, and at least a portion of said locator-pin is disposed within one of said one or more cross-pin openings in said differential case;
instructing said pair of cutter grippers to open;
closing said pair of cutter grippers to grippingly engage a cutter within a gripper groove in an outer surface of said cutter;
inserting said cutter through one of said one or more differential case windows to a start position within said hollow portion of said differential case by instructing said lathe turret to move toward said differential case, wherein in said start position said cutter is aligned with said first spindle and said second spindle;
inserting said first spindle through said opening in said first tubular portion of said differential case until a first end portion of said first spindle is received with a spindle-receiving portion in a first side of said cutter;
inserting said second spindle through said opening in said second tubular portion of said differential case until a first end portion of said second spindle is received with a spindle-receiving portion in a second side of said cutter;
opening said pair of cutter to grippers to grippingly disengaging said cutter grippers from said cutter;
removing said cutter gripping assembly from within said hollow portion of said differential case by instructing said lathe turret to move away from said differential case;
instructing said first and second spindles to spin;
machining a first internal machining surface by retracting said first spindle at a same rate as said second spindle extends; and
machining a second internal machining surface by extending said first spindle at a same rate as said second spindle retracts.

2. The method of machining an internal surface of a differential case of claim 1 , wherein said first internal machining surface is a first differential side gear surface and wherein said second internal machining surface is a second differential side gear surface.

3. The method of machining an internal surface of a differential case of claim 1 , further comprising the step of:
returning said cutter to said start position;
opening said pair of cutter grippers of said cutter gripping assembly;
instructing said lathe turret to move toward said differential case to said start position;
closing said pair of cutter grippers to grippingly engage said gripper groove in said outer surface of said cutter; and
instructing said lathe turret to move away from said differential case until said cutter is no longer disposed within said hollow portion of said differential case.

4. An apparatus for machining an internal surface of a differential case, comprising:
a lathe comprising a programmable computer, a lathe turret, a first spindle, a second spindle and a tabletop, wherein said lathe turret has an outer surface having one or more substantially flat mounting surfaces;
a differential case having a first end portion, a second end portion, an intermediate portion, an inner surface and an outer surface;
wherein said inner surface and said outer surface defines a hollow portion therein, wherein a first tubular portion extends axially outboard from said first end portion of said differential case, wherein a second tubular portion extends axially outboard from said second end portion of said differential case, wherein an output shaft opening in said first tubular portion of said differential case is aligned with an output shaft opening in said second tubular portion of said differential case, and wherein one or more cross-pin openings extend from said inner surface to said outer surface of said differential case;

a first cradle, wherein at least a portion of an outer surface of said first cradle is in direct contact with at least a portion of said outer surface of said first tubular portion of said differential case;
a second cradle, wherein at least a portion of an outer surface of said second cradle is in direct contact with at least a portion of said outer surface of said second tubular portion of said differential case;
a locator-pin, wherein at least a portion of said locator-pin is disposed within one of said one or more cross-pin openings in said differential case;
a first articulable clamping arm, wherein at least a portion of said first articulable clamping arm is in direct contact with at least a portion of said outer surface of said first tubular portion of said differential case;
a second articulable clamping arm, wherein at least a portion of said second articulable clamping arm is in direct contact with at least a portion of said outer surface of said second tubular portion of said differential case;
a turret-mounting member having a first end portion, a second end portion, a first turret attachment member, a second turret attachment member and a third turret attachment member;
wherein at least a portion of said first turret attachment member, at least a portion of said second turret attachment member and at least a portion of said third turret attachment member is integrally connected to at least a portion of said one or more substantially flat mounting surfaces of said lathe turret;

a gripping apparatus is integrally connected to at least a portion of said turret-mounting member;
wherein said gripping apparatus further comprises a first scissor arm in driving engagement with said scissor pin, a second scissor arm in driving engagement with said scissor pin, a first dowel pin in rotating engagement with said first scissor arm, a second dowel pin in rotating engagement with said second scissor arm, a first cutter gripper integrally connected to an end of said first scissor arm opposite said scissor pin, and a second cutter gripper integrally connected to an end of said second scissor arm opposite said scissor pin;

a cutter having an intermediate portion, a first side, a second side and an outer surface;
wherein a first spindle attachment portion on said first side of said intermediate portion of said cutter has a spindle-receiving portion for receiving at least a portion of a first end portion of said first spindle;
wherein a second spindle attachment portion on said second side of said intermediate portion of said cutter has a spindle-receiving portion for receiving at least a portion of a first end portion of said secon

Assignees

• Dana Automotive Systems Group

Inventors

• Joder Wayne C
• Sparks Jared
• Thomas Steven W

Classifications

• B23B29/03

  Boring heads · CPC title

• B23B29/02 Primary

  Boring bars · CPC title

• B23B3/24 Primary

  the tools of which do not perform a radial movement; Rotary tool heads therefor · CPC title