US3712094A

US3712094A - Gear rolling machine

Info

Publication number: US3712094A
Application number: US00112706A
Authority: US
Inventors: C Motz; R Anthony
Original assignee: Lear Siegler Inc
Current assignee: Nachi Machining Technology Co
Priority date: 1971-02-04
Filing date: 1971-02-04
Publication date: 1973-01-23
Anticipated expiration: 1990-01-23
Also published as: GB1358781A; DE2205329A1

Abstract

Machine for rolling a gear with a gear-like die which includes means for measuring and/or controlling the final separation between the axes of the gear and die so as to produce uniform size finish-rolled gears.

Description

United States Patent 1 1 I 1111 3,712,094

Motz et al. [4 1 Jan. 23, 1973 [54] GEAR ROLLING MACHINE 3,552,167 1 1971 Bergi et al. ..72/108 x [75] Inventors: Carl Mm, Russell Anthony, 3,533,258 10 1970 Leonard, Jr. et al. ..72/108 both of Harper Woods Mich 2,423,932 7/1947 Fmzel ..72/102 2,726,541 12/1955 Sims ...73/88.5

Assign: Lear Siegler, Inc Santa Monica 3,389,588 6/1968 Remhardtetal ..72/8

Calif.

[22] Filed: Feb. 4, 1971 [21] Appl. No.1 112,706

Primary ExaminerMilton S. Mehr Att0rney-Whittemore, Hulbert & Belknap [57] ABSTRACT [52] U.S. Cl. ..72/21, 72/94, 72/102 Machine for rolling a gear with a gear-like die which [51] Int. Cl. ..B2lh 5/02 in ludes mean for meas ring n /0r controlling the [58] Field of Search ..72/102, 108, 35, 34, 32, 31, final separation between the axes of the gear and die 72/104, 21, 25, 94, 22; 29/1592 so as to produce uniform size finish-rolled gears.

[56] References Cited 8 c1 9 D F UNITED STATES PATENTS l,240,9l9 9/l9l7 Anderson ..72/l02 PATENTEDJAN23I973 3.712.094

SHEET 1 [1F 2 GEAR ROLLING MACHINE BRIEF SUMMARY OF THE INVENTION In gear rolling a partially formed gear is finish-rolled by rolling it in mesh with one or more gear-like dies under conditions which establish relatively great pressure between the teeth of the gear and die or dies. Where this operation is carried out by engaging a gear with a single die, it has been found that small variations in size of a series of work gears prior to rolling are not completely eliminated. This is in many cases at least partly because of distortion of the frame of the machine under the relatively massive loads imposed in gear rolling.

In accordance with the present invention means are applied directly between the gear support and the die support to control the final separation between the axes of the gear and tool.

In a simple case, this means may simply be constituted by a rigid abutment. In other cases it may take the form of highly accurate measuring means and may include means for developing a signal which will terminate the application of rolling pressure, either abruptly or under a predetermined program including initial dwell and subsequent reduction in pressure.

Another alternativeis to provide a rigid abutment associated with pressure sensing means so that forces continue to be applied until the work gear is sufficiently reduced to permit the abutment to assume a predetermined loading.

The invention is applicable not only to single die rolling, but also tosituations in which a pair of opposed dies are provided.

BRIEF DESCRIPTION OF THE DRAWINGS tion, showing the invention applied to opposed rolls.

FIGS. 8 and 9show fragmentary elevational views partly in section, of modifications of the machine shown in FIG. 7.

DETAILED DESCRIPTION Referring first toF-IG. I there is illustrated a gear rolling machine comprising a frame 10 having a forwardly extending base 12, avertical column 14, and a forwardly extending top portion 16, the whole constituting whatmay be aptly described as a C-frame. Mounted for-vertical movement at the front side of the column 14 by ways 18, there is provided a knee having stocks 22 thereon which support a work gear W for rotation..Secured to the underside of the forwardly projecting top frame portion I6isa die support 24 which is illustrated'as connected to the top portion 16 for angular adjustment'about a vertical axis by suitable means such as a piloting disc 26.

A shaft .28 is journaled in the support 24 and carries a gear-like rolling die D. Means diagrammatically indicated asa motor drive 30 'is provided for driving the die in rotation.

The knee 20 is connected to power mechanism diagrammatically indicated as a'piston and cylinder device 32 for effecting vertical movement of the knee and for applying rolling forces between the teeth of the die D and the work gear W.

It will be appreciated that the forces acting directly between the die D and the gear W tend to distort the C- shaped frame 10 of the machine. While the frame is massive and substantially rigid, nevertheless under the relatively great forces imposed, deflections of a few thousandths or tens of thousandths of an inch occur.

As a result, if a series of work gears differ in pitch diameter by corresponding small amounts are rolled in the machine, it has been found that while the work gears are reduced in pitch diameter and have the surfaces of the teeth improved by the rolling action, nevertheless the difference in sizes of the work gears is not completely eliminated. In other words, the finished gears continue to show some divergence in pitch diameter.

In accordance with the present invention this divergence in finish-rolled diameter of a series of work gears is substantially completely eliminated by providing an abutment block 34' in position to act substantially directly between the work support for the gear W and the tool support for the die D. Specifically, the block 34 is shown as engaging between the top of one of the stocks 22 and the underside of the die support 24. It will of course be appreciated that if considered necessary a second identical abutment may be interposed between the die support 24 and the other work supporting stock 22.

It will be apparent that forces applied by the device 32 will continue to move the knee 20 upwardly, irrespective of any deflection or bending which may take place in the frame 10 until the axes of the work gear and die reach a predetermined spacing as determined by the block or abutment 34. Accordingly, with this arrangement a series of work gears which differ by small amounts in pitch diameter prior to the gear rolling operation, will all have identical or substantially identical pitch diameters after the rolling operation has been completed.

. In carrying out the gear rolling operation it is only necessary to insure that the abutment 34 is solidly engaged to limit further upward'movement of the knee 20 and that the parts remain in this position until the gear has made at least a complete revolution and preferably a number of revolutions.

It will of course be appreciated that the rolling operation of the gear involves plastic deformation of material of the teeth as well as elastic deformation. Accordingly, the dimensions of the abutment 34 will be such as to take into account the elastic deformation so that upon removal from the machine, the finish-rolled gear in unstressed condition will have the required pitch diameter.

In the foregoing description the block 34 has been described as a simple abutment. It may however, take the form illustrated in FIG. 2 where a block 40 is provided with an adjustableabutment screw 42.

A further embodiment of the invention is illustrated in FIG. 2 where, if desired, means are provided in association with the block 40 (or the block 34 as illustrated in FIG. 1) responsive to pressure. Such means may for example take the form of a strain gauge, transducer, or other pressure responsive means as illustrated at 44 having electrical connections 46 leading to suitable control mechanism for controlling the device for feeding the knee upwardly. This may of course take the form of solenoid controlled valves for controlling the application of fluid under pressure to the cylinder of the piston and cylinder device 32.

As the knee is moved upwardly relatively massive forces are developed between the die and gear, causing plastic deformation of the material of the gear teeth. As this deformation of the gear teeth continues, with accompanied reduction in size of the pitch diameter of the gear, eventually the abutment 40 will be solidly engaged between the work and die support. The initial engagement will take place with minimum force, and the maximum force applied by the actuating device 32 will continue to be applied. As further plastic and elastic deformation of the gear teeth takes place, the division of total force applied by the piston and cylinder device 32 changes and eventually, the force applied to the gear is only that required to produce elastic deformation thereof. The application of increased force by the piston and cylinder device 32 will have no effect on the gear but will merely apply greater force to the abutment 40.

With this arrangement the pressure sensitive means 44 may be selected or adjusted so as to terminate or gradually reduce the application of lifting force to the knee when a predetermined force has been applied to the abutment.

Referring now to FIG. 3 there is illustrated an arrangement in which the separation between the axes of the die D and the work gear W is measured by a sensitive indicator 50 which may be in the form of a dial indicator having an indicating needle 52 and a plunger 54 engageable with the underside of the die support 56. The indicator 50 rests on the knee 20. In its simplest form the operator may merely observe the needle 52 and discontinue application of force to the knee 20 when the indicator shows that the axes of the gear and die have reached the required minimum separation. Preferably however, the indicator includes contacts connected to conductors 58 which operate upon a predetermined reading of the indicator to effect automatic control of the application of force to the knee 20.

The means for automatically terminating the gear rolling operation when the work gear has been reduced to a required dimension may of course operate to effect abrupt termination of the application of upwardly directed force to the knee and permit or provide for downward movement of the knee to a clearance position. However, it is normally desirable to use the signal established when the axes between the die and gear reach a predetermined spacing to initiate a termination program which may include continued operation for a predetermined brief interval, followed either by an abrupt separation or a first gradual separation between the gear and die and then by an abrupt separation to unloading and loading position.

Referring now to FIG. 4 there is illustrated a modified arrangement in which the die support 60 carries a die here designated 62, which is mounted on a spindle 64. The spindle 64 carries a pitch abutment disc 66. The knee of the machine is illustrated at 68 and ineludes stocks 70 carrying a spindle 72 on which the work gear W is mounted. The shaft 72 carries a pitch abutment disc 74 which is adapted to engage directly with the pitch abutment disc 66 when the axes of the gear and die have reached the predetermined desired final position.

The discs 66 and 74 are referred to as pitch abutment discs because they have diameters respectively equal to the pitch diameters of the gear and die. Accordingly, when the gear has been reduced to its required dimension, the pitch abutment discs constitute abutment means preventing further infeed and at the same time, the continued rolling operation takes place without appreciable slippage between the pitch abutment discs.

Referring now to FIG. 5 there is illustrated a further embodiment of the invention. In this case an indicator 80, having contacts or switch means connected to external conductors 82, is carried by a sleeve 84 which is vertically adjustable on a rod 86 by fine adjustment means (not shown) and including a clamp 88 to lock the indicator in adjusted position. The rod 86 extends through a bracket 90 fixed to the tool support 24 and a coarse adjustment is provided by moving the rod 86 through the bracket 90 and fixing it in adjusted position by a clamping screw 92. The indicator of course is provided with a plunger 94 which engages the knee 20.

This device operates exactly in the same manner as the arrangement illustrated in FIG. 3, but provides a coarse adjustment operable when changing over from differently dimensioned parts.

Referring now to FIG. 6 there is illustrated an arrangement in which the tool support, here designated 100, carries a pneumatic gauge 102 having a downwardly extending proximity portion 104 adapted to approach the upper surface 106 of the knee, here designated 108. Air under pressure is supplied to the gauge through a conduit 110 and the relative position between the knee 108 and the tool support 100 determines the pressure within the gauge, which is used to provide a reading on a dial 112. At the same time, the pressure variation may be used to control the application of upward forces to the knee.

Referring now to FIG. 7 there is illustrated an arrangement in which the work gear W is rolled between a pair of opposed dies D1 and D2. The C-shaped frame is diagrammatically indicated at and the knee 122 is movable upwardly by power means diagrammatically indicated as the piston and cylinder device 124. It will be appreciated that the illustrated construction mounts the upper die D1 in a fixed position and that rolling forces are applied to the work gear W by upward movement of the lower die D2 and by appropriate upward movement of the work gear W to maintain it centralized between the upper and lower dies. The dies DI and D2 are driven in timed relation by gearing including gears I26 and 128 which are appropriately geared together to provide for accurately timed rotation.

In accordance with this embodiment of the invention an abutment 130 is positioned between stocks 132 and 134 supporting the upper and lower dies. Accordingly, upward movement of the lower die is continued until such movement is arrested by the abutment 130, at which time the axes between the upper and lower dies are spaced apart a predetermined distance independent of any deflection which may have occurred in the C- frame 120.

As previously suggested, the block or abutment 130 may be provided with pressure sensitive means such for example as a strain gauge diagrammatically illustrated at 136 which may be employed to transmit a signal to control the application of pressure to the piston and cylinder device 120.

Referring now to FIG. 8 there is illustrated an embodiment of the invention similar to that illustrated in FIG. 7 except that instead of employing a rigid abutment interposed between the die and gear supports, there is provided a gauge 140 having a plunger 141 adapted to engage a rigid element 142 on the support for the upper die D1. The gauge 140 is mounted on rigid support structure 144 carried by and movable with the knee 146. Again, the gauge or indicator 140 is provided with circuit controlling means and external conductors 148 leading to controls for the feed device 124 (FIG. 7).

FIG. 9 diagrammatically illustrates the application of pitch abutment discs 150 to the dies D1 and D2 associated with a pitch abutment disc 150 mounted on the arbor 154 which supports the work gear W. It will be appreciated that as the knee, here designated 156, moves upwardly the spacing between the axes of the dies D1 and D2 decreases until the pitch abutment discs engage, thus limiting further upward movement of the knee 156 and further reduction in size of the work gear W.

In any of the foregoing systems the control means which controls the continued application of force producing relative infeed of the die or dies relative to the gear, may be actuated by means sensing the position of the die or dies relative to the gear, or it may be actuated by attainment of a predetermined pressure by rigid abutment means. The programs initiated by the controls may of course include simple reversal of die movement or it may include a predetermined dwell followed by abrupt or gradual outward movement of the die.

The invention is applied to a gear rolling machine in which the frame of the machine is generally C-shaped. The column 14 constitutes an intermediate portion of the frame and the parts 12 and 16 constitute limbs extending laterally from the intermediate portion in the same direction. By the present invention the deflection of the frame which inherently occurs as a result of the relatively great forces applied in the gear rolling operation, is not permitted to affect the dimensional accuracy of the finished part since this is determined by means controlling the actual separation between the axis of the gear and the axis or axes of the rolling tool or tools employed.

In the simplest operation embodying the present invention, rigid abutment means are provided to limit the approach between the axes of the work gear and the die or dies, and feeding pressure is applied for a sufficient interval to assure that the amount of infeed is sufficient to bring about engagement of the abutment means and preferably to continue rotation of the gear and die or dies for a brief predetermined interval. Thereafter, the die or dies and work gear are separated, either with an initial gradual separation followed by abrupt separation to loading and unloading position, or by abrupt separation to such position.

The rolling of gears may be divided into rolling from the solid, in which case the work piece starts out as a cylindrical blank; or finish-rolling, m which case the work piece has been rough machined either by cutting, rolling, or otherwise prior to the finishing operation. The present invention basically controls the final size of the finish-rolled gear and hence, is most applicable to a finish rolling operation. However, it is applicable in many cases to rolling from the solid, particularly where conditions are such that no subsequent finish rolling operation is to be performed.

What we claim as our invention is:

1. A gear rolling machine comprising a generally C- shaped frame having an elongated intermediate portion, and limbs extending laterally in the same direction from said intermediate portion, a slide movable longitudinally on said intermediate portion, rotary supports on one of said limbs and said slide for a rotary gear-like die and a rotary work piece to have teeth thereon rolled in pressure contact with teeth on the die, drive means for driving one of said supports in rotation, feed means connected between said slide and said other limb for moving said slide to move one of said rotary supports generally radially of the other to cause plastic deformation of metal of the teeth of the work piece, and control means responsive substantially directly toactual spacing between the axes of said die and work piece to control movement of said slide to provide for accurate sizing of the work piece independent of any deformation of said frame.

2. A machine as defined in claim 1 in which said control means comprises a rigid abutment acting substantially directly between said supports to limit feed movement of said slide.

3. A machine as defined in claim 1 comprising an abutment acting substantially directly between said supports, and means responsive to the pressure applied to said abutment to control operation of said feed means.

4. A machine as defined in claim 1 in which said control means comprises measuring means for measuring the spacing between the axes of said rotary supports.

5. A machine as defined in claim 4, and means responsive to a predetermined spacing between the axes of said rotary supports to control said feed means.

6. A machine as defined in claim 1 in which a single die is employed with a gear.

7. A machine as defined in claim 1 in which a pair of dies are employed at opposite sides of a gear and in which the control means is directly responsive to spacing between the dies, the work piece being centered between the dies.

8. A machine as defined in claim 1 in which the rotary work piece is in the form of a gear having teeth provided with a small amount of excess material to be distributed by plastic deformation to reduce the pitch diameter of the gear to a required dimension.

Claims

1. A gear rolling machine comprising a generally C-shaped frame having an elongated intermediate portion, and limbs extending laterally in the same direction from said intermediate portion, a slide movable longitudinally on said intermediate portion, rotary supports on one of said limbs and said slide for a rotary gearlike die and a rotary work piece to have teeth thereon rolled in pressure contact with teeth on the die, drive means for driving one of said supports in rotation, feed means connected between said slide and said other limb for moving said slide to move one of said rotary supports generally radially of the other to cause plastic deformation of metal of the teeth of the work piece, and control means responsive substantially directly to actual spacing between the axes of said die and work piece to control movement of said slide to provide for accurate sizing of the work piece independent of any deformation of said frame.