Control of tooth flank grinding machines for helical gears

Claim 2

In a tooth flank grinding machine for helical gears operating in accordance with the indexing generating method and having control apparatus determining the length of stroke of the grinding means of the machine in the traverse of said means over th generating zone, the improvement comprising position-limiting means in said control apparatus varying the reversal points of the grinding strokes, said means including parts movable in coordinated relationship with the stroke of said grinding wheels, members cooperable with said movable parts for causing the length of grinding stroke to increase from a minimum at the beginning of the traverse of the generating zone to a maximum in a central region of the zone, and other members cooperable with said movable parts to reduce the length of stroke again towards the end of the traverse of said zone.

Claim 3

A machine according to claim 1 in which said control apparatus controls the movements of a ram supporting the grinding means and comprises a first switch means and a control plate means having a relative motion to said first switch means determined by the rectilinear component of the generating motion between the workpiece and the grinding means, means being provided for adjusting the relative position of the control plate means and the frist switch means, control stop means having spaced stop elements operable in conjunction with said control plate means, a second switch means cooperable with said stop elements to define limits in said rectilinear motion direction, of a zone of motion of said second switch means, switch drive means actuating said relative motion of said first switch means in a reciprocating manner in synchronism with the ram motion and at an angle to said recilinear component direction corresponding to the helix angle of the workpiece teeth.

Claim 4

A machine according to claim 2, wherein said first switch means is adapted to operate without physical contact with said control plate means.

Claim 5

A machine according to claim 2, wherein a nut carries said first switch means and a screw spindle coupled to the reciprocating drive of the ram supporting the grinding means has said nut threaded upon it whereby the first switch means is reciprocated in synchronism with the ram motion.

Claim 6

A machine according to claim 2, wherein said control plate means includes spaced linear stop members, the zone of travel of said first switch means being defined by the boundaries of the zone extending between said spaced linear stop members.

Claim 7

A machine according to claim 5, wherein means are provided to slidably mount said control plate means in the control apparatus, said linear stop members being mounted on said control plate means to be adjustable relative to the sliding direction of the control plate means, the sliding movement of said control plate means being directed at an angle relative to the linear stop members.

Claim 8

A machine according to claim 6, wherein a part of the machine performing the rectilinear component of the generating motion relative to a rotating workpiece table has a reducing transmission forming a connection to said control plate means to actuate said sliding movement of said control plate means.

Claim 9

A machine according to claim 5, wherein said second switch means cooperates with said stop elements to define the boundaries of the zone of travel of the first switch meAns, and drive means actuating motion of said second switch means in a recirpocating manner relative to said stop elements and in synchronism with the motion of said ram.

Claim 10

A machine according to claim 8, wherein a nut carries said second switch means and a screw spindle coupled to the reciprocating drive of the ram supporting the grinding means has said nut threaded upon it whereby the second switch means moves in synchronism with the ram motion.

Claim 11

A machine according to claim 1, wherein a control cam is coupled to said control plate means to be displaced synchronously therewith, said control cam determining the generating velocity of the machine and being arranged in such manner that the velocity decreases with increase of ram stroke and increases with decrease of ram stroke.

Claim 12

A machine according to claim 10, wherein said control cam has a middle zone corresponding to the zone of maximum ram stroke, a linear profile being formed on the cam in said middle zone parallel to the displacement direction of the cam.

Claim 13

A machine according to claim 10, wherein said control plate means includes a control plate slidably mounted in the control apparatus and movable in synchronism with the ram, said stop members and the control cam being carried by said control plate, said cam comprising two control bars that are adjustable angularly relative to the control plate, said two bars representing opposite end regions of the cam profile.

Claim 14

A machine according to claim 10, wherein a motor producing the generating motion of the machine is provided with a regulating potentiometer to vary the velocity thereof, said cam having a follower member forming a regulating element of the potentiometer.