Gm Global Technolgoy Operations, Inc.

George Thomas Winterhalter

Bruce Steven Shimanovski

Sanjay Mahasukhlal Shah

Mircea M Ghiran

Mike M Ghiran

Terry Andrew Kent

Romuald Gmurowski

Michael H Lovell

Glenn Mark Krcek

Ranny Joe Nunley

Daniel E Sobecki

A hydroform seal assembly includes a seal housing and an annular nozzle carried by the seal housing and sized to insert into a tube end. A first actuator moves the seal housing to insert the nozzle. A plurality of jaws are carried by the seal housing and are movable radially inward into clamping engagement with the tube to clamp the tube onto the annular nozzle. A cam bushing is movably mounted within the seal housing, surrounds the jaws, and has cam surfaces complimentary with cam surfaces provided on the jaws so that movement of the cam bushing relative the jaws will cam the jaws radially inward. A backup cam is movable within the seal housing. The cam bushing and backup cam have complimentary cam surfaces by which movement of the backup cam will forcibly move the cam bushing relative the seal housing. A second actuator moves the backup cam.

Hydroform tube sealing assembly

Hydroforming apparatus is provided with retractable part locators that are adapted when extended to receive and hold end portions of a tubular part to be hydroformed and thereby support and hold the part between the hydroforming dies when the dies are open. Seal units mounted on separate elevators have a retractable seal carrier and the seal carriers are adapted when the seal units are elevated to advance and initially engage the respective tubular part end portions while the part is being so held. The part locators are adapted to release the end portions of the part and retract out of the way of the seal carriers to permit the seal carriers to then further advance on the respective end potions of the part to a position closely adjacent the end faces of the dies while also centering the part lengthwise with respective to the dies prior to die closure. The seal unit elevators are adapted to lower the seal units with the tubular part to a position aligning the end portions of the part with open ends of the die cavity when the dies close. And the retractable part locators, following the hydroforming of the part and elevation of the part with the seal units by the seal unit elevators, are adapted to again extend and clamp the now hydroformed part to the part locators prior to disengagement of the seal carriers from the part.

Hydroforming apparatus with retractable part locators

The seal units that form part of a hydroforming apparatus that further includes dies for hydroforming parts are each provided with a tubular part locator for locating and clamping a tubular part in alignment with the seal unit. The part locator basically comprises a locator member, a pair of pivot arms and a backup member wherein the locator member and the pivot arms together with the seal unit are supported by an elevator that aligns the seal unit and the locator member with the hydroforming dies when the latter close on the tubular part. The locator member has a concave surface and guide surfaces wherein the concave surface has a shape conforming to the outer surface of the part and the guide surfaces are adapted to guide an end portion of the tubular part onto the concave surface of the locator member and thereby into alignment with the seal unit. The pivot arms each have a concave surface also conforming to the outer surface of the part and are adapted on pivoting to clamping positions to clamp the end portion of the part on the concave surface of the locator member. The backup member is adapted to hold the pivot arms in their clamping position during hydroforming of the part and may also include a concave surface that is adapted to clamp the end portion of the tubular part on the concave surface of the locator member in cooperation with the concave surface of the pivot arms.

Tubular part locator for hydroforming apparatus

A method for cutting an 'O' ring retention groove around the cutting edge of a hydropiercing die button. A groove machining tool is given a convex curved end surface the radius of which is slightly less than or, at most, substantially equal to the tightest concave radius that the end surface will have to sweep through as the groove is cut. Consequently, an accurate, slightly curved groove bottom surface is created for the 'O' ring, while the machining tool will not bind as it moves through the tightest concave portion of the cutting path.

Method for machining an 'O' ring retention groove into a curved surface

An apparatus for in-die piercing of a tube as it is hydroformed creates a sharp edged, non countersunk hole, while sealing against pressurized fluid loss and ejecting the slug cleanly from the apparatus. A sharp edged die button inset into one of a pair of die blocks includes a hole shaped cutting edge surrounded by a compliant face seal flush with the cavity between the die blocks. A plunger is slidable within a central bore in the die button from a closed position flush with the cutting edge to a partially retracted pierce position, and finally to a further retracted ejection position. An ejection chute in the same die block opens into the bore at one end, at a point between the pierce and ejection positions of the plunger, and also opens at the other end out of the die block. The plunger is sealed relative to the die button bore. The plunger is retained in closed position until the tube is fully hydroformed to final shape, and the outer surface of the tube engages the face seal. Then, the plunger is retracted to pierce position, allowing a slug to be blown out through the cutting edge. The face seal and plunger seal prevent the loss of fluid. Then, the tube is de pressurized, and the plunger retracts farther, allowing the slug to be ejected.

Apparatus for piercing hydroformed part

A seal device for a hydroforming press includes a housing having a bore and a seal carrier slidable within the housing bore. The seal carrier has a bore which fits closely outside of the end of tube to be hydroformed. A V-shaped locator rigidly mounted relative to the housing aligns the end of the tube placed thereon with the carrier bore. A carrier actuator is operable to move the seal carrier between a retracted position away from the end of the tube to an extended position over the end of the tube. A resilient elastomeric annular seal carried by the seal carrier encircles the outer surface of the tube. A seal actuator carried on the seal carrier compresses the seal upon relative movement between the seal actuator and the seal carrier. A stop is engaged by the seal actuator as the seal carrier approaches the extended position so that subsequent further movement of the seal carrier compresses the seal against the tube. The locator and a tube backup fixed to an upper bed of the press encircle the tube when the press is closed, reacting against the tube when it is pressurized. A travel limit block provides a reaction member against which the locator reacts to prevent relative movement between the seal device and the press during forming.

External seal device for tube hydroforming

A seal device for a hydroforming press includes a housing having a cylindrical bore and a cylindrical seal carrier slidable within the housing bore. The seal carrier has a bore and a tube support which fit closely on outside and inside of the end of the tube to be hydroformed. An actuator is operable to forcibly move the seal carrier from a retracted position withdrawn away from the end of the tube to an extended position in which the seal carrier is installed over the end of the tube. A resilient elastomeric annular seal is carried by the seal carrier and encircles the outer circumference of the tube with some clearance. A seal actuator carried on the seal carrier compresses the seal upon relative movement between the seal actuator and the seal carrier so that the seal is forced radially inwardly to seal against the tube. A stop is engaged by the seal actuator as the seal actuator approaches the fully extended position so that the subsequent further movement of the seal carrier then compresses the seal against the tube. The stop may be fixedly mounted to the housing, or alternatively, the die may serve as the stop by closing the dies about the tube so that the movement of the seal carrier to the extended position causes the seal actuator to engage the die.

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Berkley, MI, United States of America

George Thomas Winterhalter