Friction-welding apparatus and method

Claim 2

A friction-welding machine of the kind for bonding two weld pieces across a common interface by pressing the pieces together at their interface and moving the pieces in rubbing contact until the interface is brought to a plastic condition, comprising: fixture means for securing the pieces together; drive means; rack and pinion means operatively coupled between: the drive means and a fixture for one of the weld pieces; programming means operatively associated with the drive means to selectively regulate operation of the drive means and relative motion of the weld pieces; and the drive means being a hydraulic jack, a source of fluid under pressure being in communication with the jack by means of a control valve, the control valve being responsively associated with the programming means to regulate fluid flow to the hydraulic jack.

Claim 3

The combination of claim 1 wherein the one weld piece is secured for rotation with a rotatable spindle operatively connected to said pinion means and the other weld piece is secured against rotation by a suitable tailstock, said tailstock being movable and having loading means associated therewith for urging said weld pieces into engagement at their interface.

Claim 4

The combination of claim 1 wherein said drive means are capable of variable speed operation effective to vary the rate of relative motion of the weld pieces and said programming means are effective to regulate the speed of said drive means.

Claim 5

The combination of claim 3 wherein said programming means are effective to regulate said drive means for initially providing a high relative rate of motion between the weld pieces for bringing their interface to a plastic condition and thereafter providing a lower relative rate of motion between the weld pieces suitable for plastic working of material at the interface.

Claim 6

The combination of claim 1 wherein said jack includes a piston member operatively connected to said rack, said piston member being unidirectionally and linearly operable in response to said programming means.

Claim 7

The combination of claim 5 wherein said programming means includes means for closely controlling the distance through which the piston member is operable and the speed of the piston member during each weld cycle to precisely regulate relative motion between the weld pieces.

Claim 8

The combination of claim 2 wherein the pressure loading means are operatively associated with the weld piece fixtures and said programming means for urging the weld pieces into engagement at their interface in response to said programming means.

Claim 9

In a friction-welding machine of the kind for bonding two weld pieces across a common interface by pressing the pieces together at their interface while the pieces are moved in rubbing contact until the interface is brought to a plastic condition, comprising: fixture means for holding the pieces; loading means for pressing the pieces together; drive means operatively connected to the fixture means for moving the pieces in rubbing contact, and wherein said drive means includes means for producing a precisely controlled, limited amount of linear motion during the welding portion of each weld cycle, said drive means comprising a double-acting hydraulic cylinder having its rod end operatively connected to the fixture means through translating means; programming means operatively associated with said drive means and effective to selectively regulate energy delivered to the interface of the weld pieces, the programming means including means for closely controlling the distance through which the piston member is operable and the speed of the piston member during each weld cycle to precisely regulate relative motion between the weld pieces; a source of fluid under pressure being in communication with said hydraulic cylinder by valve means which are responsively coupled to said programming means; and said hydraulic cylinder having its head end and rod end in separate fluid communication with said valve means and having its rod operatively coupled with said translating means, said valve means being of a solenoid-operated three-position type and said programming means comprising switch means operable to a Weld position to actuate the valve means to a position for communicating fluid to one end of the cylinder, a Reset position to actuate the valve means to a position for communicating fluid to the other end of the cylinder and an Off position for actuating the valve means to a position for isolating the fluid source from both ends of the cylinder.

Claim 10

In a friction-welding machine of the kind for bonding two weld pieces across a common interface by pressing the pieces together at their interface while the pieces are moved in rubbing contact until the interface is brought to a plastic condition, comprising: fixture means for holding the pieces; loading means for pressing the pieces together; drive means operatively connected to the fixture means for moving the pieces in rubbing contact, and wherein said drive means includes means for producing a precisely controlled, limited amount of linear motion during the welding portion of each weld cycle, said drive means comprising a double-acting hydraulic cylinder having its rod end operatively connected to the fixture means through translating means; programming means operatively associated with said drive means and effective to selectively regulate energy delivered to the interface of the weld pieces, the programming means including means for closely controlling the distance through which the piston member is operable and the speed of the piston member during each weld cycle to precisely regulate relative motion between the weld pieces; a source of fluid under pressure being in communication with said hydraulic cylinder by valve means which are responsively coupled to said programming means; and said hydraulic cylinder having its head end and rod end in separate fluid communication with said valve means and having its rod operatively coupled with said translating means, said valve means being of a solenoid-operated three-position type and said programming means comprising switch means operable to a Weld position to actuate the valve means to a position for communicating fluid to one end of the cylinder, a Reset position to actuate the valve means to a position for communicating fluid to the other end of the cylinder and an Off position for actuating the valve means to a position for isolating the fluid source from both ends of the cylinder.

Claim 11

The friction-welding machine of claim 1 wherein the hydraulic motor is of a double-acting type to permit resetting of said rack and pinion between welding cycles and said variable pump has a reversible pump cam positionable by said programming means.

Claim 12

The friction-welding machine of claim 9 wherein a double-acting hydraulic control motor is operatively coupled to said pump cam to vary its position and a servovalve is interposed between the control motor and a source of fluid, the servo valve being associated with said programming means for selective operation of said control motor and positioning of said pump cam.

Claim 13

The friction-welding machine of claim 10 wherein a transducer is associated with a weld piece fixture to be rotated by the pinion to provide an electrical signal representative of the actual relative rotational speed of the weld pieces, said programming means provide an electrical signal representative of a desired instantaneous relative rotational speed for the weld pieces, first electrical summing means receive said signals from said programming means and said transducer and provide an electrical signal representative of an instantaneous desired change of relative rotational speed and accordingly of a desired position for said pump cam, second electrical summing means receive said signal from said first summing means and an output signal from a potentiometer associated with said reversible pump cam which is representative of the actual pump cam position, said second summing means to provide an output signal to said servovalve, said servovalve responsively conditioning said control motor to reposition said pump cam and provide for the desired rotational speed of the one weld piece.