US3006117A - Gear honing - Google Patents

Description

C. H. MOTZ GEAR HONING Oct. 31, 1961 5 Sheets-Sheet 1 Filed NOV. 24, 1958 INVENTOR. CAR /7 W072 Oct. 31, 1961 c. H. MOTZ GEAR HONING Filed Nov. 24, 1958 3 Sheets-Sheet 2 I [m I U W013 14 from 6Y5 Oct. 31, 1961 Filed Nov. 24, 1958 C. H. MOTZ GEAR HONING 5 Sheets-Sheet 3 I A I In! I I w l INVENTOR.

"United States Patent 3,006,117 GEAR HONING Carl Henry Motz, East Detroit, Mich, assignor to National Breach & Machine @ompany, Detroit, Mich a corporation of Michigan Filed Nov. 24, 1958, Ser. No. 775,882 6 Claims. (Cl. 511-105) The present invention relates to gear honing and more particularly, to an operation in which a hardened gear to be finished is run in mesh at crossed axes with a gearlike honing tool. The honing tool is characterized in that at least the toothed portion thereof is formed of a somewhat resilient but substantially hard resin such for example as epoxy resin containing a multiplicity of embedded abrasive particles, such as particles of silicon carbide.

According to prior practice, automatic machines for carrying out a gear honing operation have been provided in which the gear and gear-like hone while being rotated in mesh are also given a relative traverse in a direction which occupies a plane parallel to the axes of both the gear and hone. Conventionally, this. relative traverse is initiated from a starting point in which the common normal to the axes of the gear and hone lies beyond one side of the gear to be finished. The relative traverse takes place in a direction and in an amount which may be sufficient to cause this so-called common normal to traverse completely across the width of the gear or less, as conditions require. Thereafter, traverse in the opposite direction is initiated. During relative traverse, it is common practice to have the rotation between the gear and tool in one direction during traverse in one direction and to revere the direction of relative rotation when the direction of traverse is reversed.

While a honing tool of the type referred to has a relatively long life and may be used to finish many thousands of hardened steel gears, nevertheless the tool is subject to wear. Unlike a gear shaving tool, the gear honing tool tends to accommodate itself to the average gear char acteristics of a series of work gears. When a gear honing tool is new and is provided with unmodified teeth, initial contact between the teeth of the gear and hone is theoretically at a point. However, since the honing tool is subject to slow erosion, its tooth surfaces accommodate themselves to the average shape of the teeth of the gear. More specifically, after a relatively few number of gears have been honed, the teeth of the hone are longitudinally co-ncave (for external gears) so as to contact the surfaces of the teeth of the work gear throughout the overlapped extent thereof. The converse is of course true for internal gears.

Moreover, when finishing a series of gears it is found that the most severe erosion on the teeth of the one occurs during the first stroke of traverse and at a side of the teeth dependent upon the direction of rotation. Accordingly, if each gear finishing cycle is initiated from the same point and in the same direction irregular wear or erosion takes place on the teeth of the hone.

It is accordingly an object of the present invention to provide automatic controls for a gear honing machine which are effective to cause the successive cycles to be initiated in opposite directions.

It is a further object of the present invention to provide automatic controls for a gear honing machine which are effective to cause the successive cycles to be initiated in opposite directions.

It is a further object of the present invention to provide automatic controls as described in the preceding paragraph in which the end of each cycle is brought about when the center of crossed axes is located intermediate the ends of the gear. This of course means that a stroke of traverse is ended to terminate the cycle in the center of the stroke.

More specifically, it is an object of the present invention to provide automatic control mechanism for a gear honing machine efiective to insure termination of each cycle when relative traverse between the gear and hone is intermediate the ends of a stroke thereof and to cause each succeeding cycle to commence with relative traverse and relative rotation in a direction opposite to that or" the commencement of the immediately preceding cycle.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, illustrating a preferred embodiment of the invention, wherein:

FIGURE 1 is a fragmentary perspective view showing the essential components of a gear honing machine so far as the present invention is concerned.

FIGURE 2 is a simplified wiring diagram of the machine shown in FIGURE 1.

FIGURE 3 is a side elevation of the machine shown in FIGURE 1.

Referring now to FEGURES l and 3, the gear honing machine comprises a main frame 1%) having an overhanging head 12 and a knee 14. The knee 14 is mounted for vertical movement in ways 15 and may be continuously urged upwardly during a cycle by springs, fluid pressure, or it may be moved upwardly by a feed screw and nut device indicated at 17 to a predetermined position and locked.

Mounted on the knee is a carriage 16 movable to the right and left in the direction of the arrow designated 18. Mechanism for effecting traverse of the carriage 16 on suitable guideways indicated at 20* comprises a motor 22 having a driving worm 24 in mesh with a worm gear 26 which drives a feed screw 23 received in a nut 39.

Mounted on the slide of table 16 are a pair of stocks 32, 34 between which is mounted a gear-like member 36. The gear-like member may be a work gear to be honed or it may be a honing tool.

Carried at the underside of the head 12 of the frame is a support 38 which is mounted for angular adjustment about a vertical axis by suitable means, such as a pilot portion 39a, arcuate T-slots concentric with the motor drive shaft, and bolts 3%. The support 38 includes a spindle 49 on which is mounted a gear-like member 42 which may be a gear to be finished or a gear-like hone. Normally, in the machine illustrated the gear-like member 42 is a hone and the member 36 is a work gear so that a series of work gears may be replaced between the stocks 32 and 34 as they are finished.

Means are provided for rotating the hone 42 and this means comprises a motor 44 driving through beveled gears indicated generally at 46 and change gears 48 and St The gear 50 carries the shaft 40 on which the gearlike hone 42 is mounted.

The motors 22 and 44 are adapted to be energized simultaneously. Rotation of the motor 22 results in traverse of the table 16 in the direction of the arrow 18. Operation of the motor 44 results in positive rotation of the gear-like bone 42.. The work gear 36 is mounted for free rotation and is rotated solely through the meshed engagement between the bone and the gear.

In practice, the gear and hone are brought into mesh at crossed axes. Normally, the contact between the teeth of the gear and tool occupies a relatively small zone. This zone may be extended as previously described it the teeth of the hone have been worn to a longitudinally concave or convex form. In any case, it is desirable to provide the relative traverse as described in the foregoing.

In order to make the cycle of the machine fully automatic, limit switches LS1, LS2 and LS3 are provided. The limit switch LS2 is located in a position such that the dog 52 actuates the switch in an intermediate position of a traverse stroke of the table or slide 16. A dog 54 is provided which will actuate the limit switch LS1 when the slide 16 has completed a stroke to the left. Similarly, a dog 56 will actuate the limit switch LS3 when the table or slide 16 has completed a stroke to the right as seen in the figure.

The present invention comprises a circuit controlled generally by the limit switches referred to and effective to terminate a cycle when the dog 52 actuates the limit switch LS2. This of course, occurs in the middle of a traverse stroke. Moreover, the circuit is so arranged that each succeeding cycle starts from the middle or in termediate position in a direction opposite to the direction which the immediately preceding cycle starts. It should be noticed that the motors 22 and 44 are so arranged that traverse to the right is always accompanied by rotation of the hone 42 in the same direction and traverse to the left is accompanied by rotation of the hone in the opposite direction.

While simultaneous reversal of traverse and rotation is accomplished by the circuit illustrated herein, reversal of traverse and reciprocation may be divorced so that different cycles may be used. For example, rotation may be in the same direction for a predetermined number of traverse strokes, and in the opposite direction for the remainder of the traverse. In this case, it is desirable that the direction of initial rotation of each cycle shall be directly opposite that of the immediately preceding cycle. Reversal of rotation may be controlled independently of reversal, as by a separate timer, so that a predetermined fraction of the total time of each cycle may be used in honing a particular side of the teeth of the gear.

A suitable reversing switch (not shown) may of course be provided so that the direction of hone rotation may be reversed with reference to the particular direction of traverse.

Referring now to the wiring diagram shown in FIG- URE 2, the motors 22 and 44 are illustrated as having motor control contacts FRa and RRa adapted to be energized by relays FR and RR shown in the wiring diagram.

The control circuits will be described with reference to a cycle of operation since the particular wiring diagram and the reference characters applied thereto make it substantially self-explanatory. It may be mentioned that the relays are designated by circles in the diagram containing letters designating a coil of the relay. The contact actuated by the solenoids bear general identification and are separately identified by the small letters following. For example, the relay R1 controls normally open relay contact Rla.

With the foregoing in mind, it may be assumed that the machine has been turned off and the contacts are in the position shown in the wiring diagram. It will be observed that the actuating dog 52 overlies the limit switch LS2 which is thereby maintained in the position illustrated. It may also be mentioned that the limit switches LS1, LS2 and LS3 are of the spring-urged snap acting type and occupy normal positions except when actually contacted by the associated dogs.

To initiate a cycle the start switch is momentarily depressed energizing relay R1 and closing normally open contacts Rla. These contacts complete a holding circuit around the start switch and maintain the relay R1 energized throughout the remainder of the cycle. Energization of relay R1 also closes normally open contacts R1b and this in turn furnishes the electrical supply to the control circuit.

To initiate a cycle the cycle button is momentarily depressed which energizes a clutch coil relay CC. This in turn closes normally open contacts CCa completing a circuit to relay R2. Energization of relay R2 closes normally open contact R2a, thus completing a holding cir cuit to the clutch coil CC. Relays R2 and CC remain energized until de-energized by circuit control instrumentalities later to be identified.

Means are provided for controlling the number of strokes in a cycle and this means comprises an automatic counter which includes the clutch coil CC and an impulse coil IC. The arrangement between these two coils is believed well understood but may be briefly reviewed. The clutch coil when energized results in closure of normally open contact CO1: and opening of normally closed contact CCb. The impulse counter which may be manually set for any number of strokes is actuated or counts each time it is energized and then de-energized. It will be apparent that when the forward relay PR is energized, contacts FRb are closed, thus completing a circuit to the impulse counter coil IC. When the end of any stroke is reached and the relay PR or RR is de-energized, impulse counter coil TC is de-energized and counts one.

When the predetermined number of counts is reached a mechanical connection between clutch coil CC and contacts CCa and CC?) is broken allowing the contacts to return to normal position. Clutch coil CC must be deenergized to re-establish the mechanical connection between coil CC and contacts CO1: and CCb. This mechanism is available on the market, for example, a Micro flex counter sold by Eagle Signal Corp., Moline, Illinois, made under Patents 1,794,762; 2,175,864; and 2,175,865.

Closure of relay contacts R2b completes a circuit to limit switch LS2 and normally closed relay contacts R3c and normally closed reversing contacts RRa to the forward control relay FR. This energizes the motors 22 and 44 in a forward direction which in the present instance is considered to be to the right so far as traverse of the carriage 16 is concerned. As soon as relay PR is energized a holding circuit is completed through contacts R211, limit switch LS3, contacts PRO. and contacts RRa. As soon as the table starts to move to the right, limit switch LS2 is permitted to shift to its normal position, thus terminating the circuit which initiated movement of the table and rotation of the hone. However, operation is continued through the holding circuit previously described.

When the table reaches the end of its traverse to the right, limit switch LS3 is actuated, thus breaking the circuit to forward relay FR. Actuation of limit switch LS3 results in closure of a circuit through contacts R2d, LS3, FRa, to the reverse relay RR and this of course, reverses traverse of the table and reverses rotation of the bone.

As soon as the motor 22 is reversed, slide 16 starts to move to the left. Initial movement of the slide or table 16 to the left moves the dog 56 away from limit switch LS3 and permits the limit switch to return to the position shown in the figure, which interrupts the above described starting circuit. However, at this time asecond circuit has been completed to the relay RR through the contacts Rzd, LS1, RIM and FRa. Thus, the motor continues to run and the table moves to the left to the extreme left hand position. It will be observed that as the dog 52 passes an intermediate position it actuates the limit switch LS2. This however, has no effect on the circuits then in operation.

As soon as the table reaches its left hand position, the dog 54- engages limit switch LS1. The contacts of limit switch LS1 are moved upwardly from the position shown in the diagram and complete a circuit to the forward relay FR at the same time breaking the circuit to the reverse relay RR. The circuit to the forward relay PR is through the contacts R2d, limit switch LS1, and normally closed contacts RRa. This of course, reverses the direction of rotation of both motors and initiates the traverse of the table to the right. With the foregoing operation, the table will reciprocate back and forth for a number of traverses as determined by the setting of the counter containing the impulse counter coil or relay IC.

When the counter counts out, contacts CCa open and normally closed contacts CCb close. Opening of contacts CCa does not de-energize relay R2 since at this time a circuit has been completed through contacts R2b, limit switch LS2, contacts R20 and the relay. However, eventually the table reaches the position in which the dog 52 actuates the limit switch LS2 to the position shown in FIGURE 2, thus de-energizing relay R2.

Prior to termination of the cycle, when the table reached the left hand position and counted the last stroke of traverse set on the counting mechanism, relay R3 was energized through contacts FRc and CCb and a holding circuit was established through contacts RRc and R3b. Energization of relay R3 opens normally closed contact R3c and thus prevents subsequent actuation of the starting circuit which initiated the first cycle by completing a circuit to the forward relay FR. When the table reached the intermediate position as described above, and LS2 was actuated by dog 52, the motors were stopped and the first cycle terminated. It will be noted that at that time relay R2 was de-energized but relay R3 remained sealed in.

To start the next succeeding cycle, the cycle button is momentarily depressed. It will be understood that if the machine is adapted for fully automatic operation, mechanism is provided which in effect closes the cycle switch at the proper time in the operation. Closure of the cycle switch completes the circuit to the clutch coil CC and closes normally open contact CCa completing a circuit to relay R2. When RR was energized, contact RRc opened, breaking the holding circuit to relay R3, but relay RR remains energized through contacts RZd, LS1, RRd and FRa, until LS1 is contacted by dog 56 at the end of the first stroke. The machine operates as before through a number of back and forth strokes or traverses as determined by the setting of the counter until eventually the counter counts out. When the table reaches its mid-position and limit switch LS2 is actuated,

relay R2 is de-energized and the table stops. At this time relay R3 is de-energized and normally closed contacts R30 are closed, thus setting up a circuit for initiation of the third cycle which will be in all respects identical with the first cycle.

From the foregoing it will be observed that fully auto matic mechanism has been provided which insures that relative traverse between the gear and hone is automatically terminated in mid-stroke or when the gear and hone contact each other intermediate the ends thereof. Furthermore, in addition to terminating a stroke of traverse midway beween its ends, the circuit is so arranged that alternate cycles commence with a traverse stroke to the right, whereas the remaining cycles commence with a traverse stroke to the left. This provides uniformity in hone wear and contributes to hone life as well as improved honing action.

While there has been disclosed automatic mechanism for causing each cycle to commence from a position corresponding to a mid-stroke position and also to cause successive cycles to commence with traverse in the opposite direction, these two novel method features may be practiced without the automatic mechanism disclosed herein and may be practiced by manual control of conventional starting circuits.

It is believed that the step of starting with the hone and gear meshed in an intermediate position (that is, in a position corresponding to the middle of a traverse stroke) is novel for two reasons. The first of these is that injury to the hone during loading is avoided when the gear and hone are brought into mesh in a centralized "6 position rather than adjacent the ends of their respective teeth. Secondly, a more desirable honing action results when the traverse strokes are initiated at the center of the teeth.

The drawings and the foregoing specification constitue a description of the improved gear honing in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A gear finishing machine comprising a frame, a rotary work support on said frame for a gear member, a rotary tool support on said frame for a gear-like tool member, means for effecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a result of meshed engagement between the members carried thereby, traverse drive means comprising an electric mot-or, and mechanical connections between said motor and one of said supports, cycle control means comprising a circuit including switches and switch actuating dogs movable relative to each other upon relative traverse between said supports, said switches and dogs being located to effect reversal of said motor to effect back and forth traverse of the support connected thereto, and including a switch and dog located to terminate a cycle in mid-traverse stroke with the common normal to the axes of said members intersecting a gear member on the work support.

2. A gear finishing machine comprising a frame, a rotary work support on said frame for a gear member, a rotary tool support on said frame for a gear-like tool member, means for eifecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a result of meshed engagement between the members carried thereby, traverse drive means comprising an electric motor, and mechanical connections between said motor and one of said supports, cycle control means comprising a circuit including switches and switch actuating dogs movable relative to each other upon relative traverse between said supports, said switches and dogs being located to eifect reversal of said motor to effect back and forth traverse of the support connected thereto, and including a switch and dog located to terminate a cycle in mid-traverse stroke with the common normal to the axes of said members intersecting a gear member on the work support, reversing switches for said motor, switches in said circuit effective to initiate traverse of the support connected to said motor in opposite directions on successive cycles.

3. A gear finishing machine comprising a frame, a rotary work support on said frame for a gear member, 'a rotary tool support on said frame for a gear-like tool member, means for effecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a result of meshed engagement between the members carried thereby, a slide on said frame on which one of said supports is mounted, a reversible electric motor, mechanical drive means connecting said motor and slide,

cycle control means comprising a circuit for controlling said motor, said circuit including switch-es, switch actuating dogs movable relative to said switches upon traverse of said slide, counting mechanism in said circuit, motor reversing mechanism including switches operable by said dogs at the ends of traverse strokes, and a switch and dog set located to be operated in mid-traverse stroke to terminate a cycle.

4. A gear finishing machine comprising a frame, a rotary work support on said frame for a gear member, a rotary tool support on said frame for a gear-like tool member, means for effecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a result of meshed engagement between the members carried thereby, a slide on said frame on which one of said supports is mounted, a reversible electric motor, mechanical drive means connecting said motor and slide, cycle control means comprising a circuit for controlling said motor, said circuit including switches, switch actuating dogs movable relative to said switches upon traverse of said slide, counting mechanism in said circuit, motor reversing mechanism including switches operable by said dogs at the ends of traverse strokes, and a switch and dog set located to be operated in mid-traverse stroke to terminate a cycle, said circuit including means operable to cause the first strokes of successive cycles to begin in opposite directions. a

5. A gear finishing machine comprising a frame, a rotary Work support on said frame for a gear member, a rotary tool support on said frame for a gear-like tool member, means for effecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a result of meshed engagement between the members carried thereby, a slide on said frame on which one of said supports is mounted, a reversible electric motor, mechanical drive means connecting said motor and slide, cycle control means comprising a circuit for controlling said motor, said circuit including counter means for determining the number of full traverse strokes in a cycle, switch means operable to terminate each traverse stroke and initiate a reverse stroke, and switch means cooperating with said counter means to terminate the last traverse stroke of each cycle intermediate the limits of full traverse stroke.

6. A gear finishing machine comprising a frame, a rotary work-support on said frame for a gear member, a rotary tool support on said frame for a gear-like tool member, means for effecting angular adjustment between said supports about an axis perpendicular to the axes of said supports, guide means mounting one of said supports on said frame for traverse in a plane parallel to the axes of both of said supports, means for moving one of said supports toward the other to establish pressure contact between said members, means for driving one of said supports in rotation, the other support being rotatable as a'result of meshed engagement between the members carried thereby, a slide on said frame on which one of said supports is mounted, a reversible electric motor, mechanical drive means connecting said motor and slide, cycle control means comprising a circuit for controlling said motor, said circuit including counter means for determining the number of full traverse strokes in a cycle, switch means operable to terminate each traverse stroke and initiate a reverse stroke, switch means cooperating with said counter means to terminate the last traverse stroke of each cycle intermediate the limits of full traverse stroke, and switch means efifective to initiate the initial short traverse stroke of each cycle in a direction opposite to the initial short traverse stroke of the next preceding cycle.

References Cited in the file of this patent UNITED STATES PATENTS 1,960,841 Fellows May 29, 1934 2,232,408 Shaw Feb. 18, 1941 2,351,842 Seibold June 20, 1944 2,913,858 Praeg et al. Nov. 24, 1959

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