US2068913A - Centrifugal quenching - Google Patents

Description

Jan. 26, 1937. H. J. GREGG 2,068,913

v CENTRIFUGL QUENCHING v Filed Deofz, 1955 Patented Jan. 26, 1937v UNITEDI` STATES PATENT OFFICE i CENTRIFUGAL QUENCHING Hendrick J. Gregg, Waterloo, Iowa Application December 2, 1935, Serial No. 52,563

9 (Haiml. (Cl. 148-21) g The method and machine herein disclosed are planned for bringing about a uniformquenching action from the periphery inwardly of circular metallic articles, such as gears.

. In the manufacture of h( at-treated steel gears,

requiring an extraordinarily high degree of perfection in form, the customary methods of quenching result in a large percentage of scrap loss due to non-uniformity of application of the l quenching uid. The heated articles may be held in their original form by clamps under extremely high pressure; but, however great that pressure may be within practical limits, it is impossible to overcome the distortion strains set upll in the metal by immersion.v

It is now proposed to perform the quenching action by a uniform application of the quenching bath and the object of v.the invention is to attain such result through the use of centrifugal force, by building a ring of the quenching uid around the heated article and forcing the enlargement of this ring inwardly to uniformly quench at a denite rate from the periphery to the center of the article; or to exhaust quench fluid at any given point between periphery and hub thereby resulting in sectionalized hardness.

It is also a purpose of the invention to provide mechanical improvements in machines for such work whereby a preliminary forming or correcting operation may be performed by the machine by the application of pneumatic or hydraulic pressure to they articles asreceived from heat treatment furnaces.

' The machine provides for carrying out the method, which machine and method are planned for pressing and quenching disc-shaped, ringshaped or cylindrical articles, is shown in the drawing in transverse vertical section.

Due to common faults in quenching processes,

o it is difficult to avoid unequal strains and ,resultant warpage in articles under treatment. In the case of expensive gears a barely measurable imperfection caused by the quench necessitates the articles `being scrapped and reprocessed.

With a view to attaining during the quencha uniform molecular set from the periphery inwardly of cylindrical or disc-shaped articles such as gears or gearv rings, in the improved process the quenching mediumis caused to travel radially over the exposed surfaces of the articles. Such action is' accomplished in a workable way by spinning the quenching iiuid in a cylindrical -container 'wherein the article to -be quenched is iirmly clamped in a central position and pref- 55 erably spun with the quenching fluid as the latter is increased in volume by the pressure of incoming fluid.

The construction used for that purpose, as illustrated in the drawing, consists of an open frame I which supports a cylinder 2. Vertically t movable within this cylinder is a piston 3 which carries at its lower end a bearing structure 4 for a rotating gear clampingA head 5. Thrust and radial bearings for head 5 are indicated at 6, 'I and 8. y 10 The head l is rotated with a coacting lower gear clamping member 9, which receives power from a drive shaft IU. A

'Ihe circular flange Il of clamping member 9 flts within the beveled edge I2 of the annular l5 flange I3 of head I, when the latter is in its lower position, clamping an article suchv asgear 43 between the gripping rings Il and I5. A plunger I6 engages the gear at itsvhub, while these rings engage the periphery of the gear. 20 I The plunger I6 is carried by a piston I 'I fltting within the piston 3. Fluid pressure for operating piston 3 is admitte'd to cylinder 2 through conduit Il and fluidunder pressure for operating piston I1 is admitted to the interior of piston 25 3 by conduit I 9. By this arrangement a like or differential pressure may be applied to the pistons. The gear 43 rests upon the ring I5 and also on a central support 20.

The product of some standard gear making 30 machines is such that the lower face of the gear which rests upon ring l5 is in flxed relationship with the face of hub 2| but the hub 22 at the opposite side of the gear is slightly variable. Therefore plunger I6 is made adaptable to this 35 variation by being capable of movement relatively to the clamping head 5. i

When the'clamping members are brought together to grip a gear, the gear is first engaged at the hub and then at the rim under a considerable hydraulic or pneumatic pressure such as is sufficient to correct warpage. of the article during heat treatment. This forming operation is therefore distinct from and preliminary to the quenching operation. The latter occurs while the gear is still under the pressure of the press, and power has been applied to shaft I0 by operation of clutch 23.

A centrifugal contact maker 24 carried by shaft I0 controls the operation of solenoid valve 25, 5i) which in turnadmits the quenching fluid through port 26 to the space between the bearing sleeve 21 and' plunger rod 28. The fluid travels from there to the space between plate 29 and the housing 30 of clamping head 5. The outlet for 55 the fluid to the gear spacci-between plate -29 of the upper clamping member 5 and the flange ugal force which enlargement is in an inward direction toward the rim of the gear, all equally radially distant points of which will be contacted simultaneously by the fluid.

Thus, with a properly centered gear a highly perfected article is assured insofar as the quench is concerned, for this takes place radially inward and the shrinkage and stresses set up in the metal are so uniform as not to distort the article, such as the commonplace dished distortion occurring with old quenching methods wherein the fluid reaches one face of the gear before it does the other.

'I'he clamping rings Il and I5 have equally spaced gripping teeth 34 and 35, and head 5 is rotated by the clamping member 9 through the article which is placed between the clamps. Bearings for the clamping member 9 are indicated at 36 and the shaft 31 for this element of the clamp is geared to drive shaft I through the gears 38. Assuming that the gears treated by the particular machine illustrated are about 18 to 20 inches in pitch diameter, the horsepower required for drive shaft I0 is approximately 'I1/2 when the speed thereof is 400 R. P. M.

The valves and fittings for controlling the operation of the hydraulic press are the same as is customary in that class of machinery, and therefore are not illustrated in detail.

In carrying out the improved process of quenching by use of the equipment illustrated, the articles to be quenched are handled singly, and when at the proper temperature, are removed from the heat treating furnace and placed upon ring I5, exactly true therewith, as determined by any desired centering means. 'I'hen the fluid pressure is admitted to cylinder 2 and piston 3, which results in the head moving downwardly against the article, firmly gripping it at the rim and the hub with any desired pressure, or a differential pressure between these points.

The pressure applied at this time has a correcting effect on the article in case it has a tendency to dish equally or unequally. At the same time the flanges I3 and II come together and substantially seal the clamping members against outward flow of the quenching fluid. The clutch 23 is then operated to drive shaft I0 and thus rotate the clamping head with the article therein. When the desired lspeed has been attained, solenoid valve 25 opens and admits the quenching fluid to the space`39 in the rotating head. From this space the uid enters the gear compartment through the openings 3l. The centrifugal force causes the fluid to rst form a peripheral ring against flange I3 without contacting gearl 43, but this ring enlarges due to continued feed of the quenching fluid under pressure into the rotating head.

'I'he uid uniformly contacts the rim of the gear and travels inwardly toward the hub but may be permitted to ilow out of the apparatus before reaching the hub through the openings 40 in the hub 4I of clamping member 9.

It is through this feature that itis possible to accomplish full hardness on the gear teeth and web, yet to retain a hot hub or soft hub which can later be easily nished machined, thus making possible savings in machining costsl not to mention other items such as flatness, roundness, improved tooth action, which is attributed to the centrifugal quenching principle.

The lower part of the frame structure I forms a tank for receiving the used quenching fluid from which it is recirculated through drain I2.

Althoughbut one specific embodiment of this invention is herein shown and described, it will be understood that details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim:

1. The method of quenching heat treated circular articles which consists in surrounding such articles with a rotating ring of quenching fluid and enlarging the ring of uid inwardly against centrifugal force and thereby quenching the article radially from the periphery toward the center.

2. The method of quenching a heat treated article which consists in rotating the article around a central axis and causing quenching uid to rotate with the article and travel inward from the periphery thereof toward the center.

3. A method of treating articles of the class described consisting in first applying pressure to a heated article for the purpose of correcting distortion thereof under the action of heat, then rotating the article on a central axis and forcing a quenching uid to flow inwardly over said article while exerting a counter centrifugal force on said fluid.

4. A centrifugal quenching machine comprising a hollow head having a gripping surface, a lower clamping member, means for rotating said head and lower clamping member and means for forcing a quenching fluid into the space enclosed by said head and lower clamping member and from the periphery thereof toward the center.

5. In a machine of the class described, a pair of gripping members mounted for rotation on a common axis, means for driving said members, hydraulic means for moving one of said members toward the other, said members being formed to carry a quenching uid when in gripping relation, means for feeding a quenching uid thereinto while said gripping members are under rotation.

6. In a machine of the class described, a clamping member mounted for rotation and means for driving said clamping member, a coacting clamping member movable toward and away from said driven clamping member and comprising a pair of relatively movable gripping elements, said clamping members being formed to receive a quenching fluid and feed said fluid from the periphery thereof inwardly against centrifugal action.

'7. A centrifugal quenching machine comprising a hollow head for covering articles to be quenched, a lower clamping member, relatively movable gripping elements for retaining articles in a central position betweensaid head and lower clamping member, means for rotating said gripping elements, means forforcing a quenching fluid into the space enclosed by said head and iowe' clamping member from the periphery toward the center thereof, and a quenching uid discharge port in said head and located between the periphery and the center thereof whereby quenching fluid does not reach the center portion around a central axis and causing quenchingv fluid to rotate with the article and travel inward from the periphery thereof toward the center Y and discharge away from said article at a point located betweenthe periphery and the center rotating the article 'on a' central axis and forcing a quenching fluid to ow around said article while exerting a counter centrifugal force on said fluid.

- HENDRICK J. GREGG.

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