JP2012081569A - Peening finishing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength of a gear tooth root radius and tooth faces by peening, enhance wear resistance, and reduce indentations due to the peening by applying vibration finishing thereafter.SOLUTION: A metal working method includes: causing a first peening medium to collide with a plurality of surfaces on the metallic gear to thereby improve the strength of the tooth roots and the wear resistance of the gear; exposing the plurality of surfaces to second peening media to thereby enhance compressive stresses (KSI) of the gear surfaces; vibrating the precisely finished medium with the gear in a container; cleaning the gear; and applying rust-proof treatment.

Description

  The present invention relates generally to a method of blasting and peening media into gears and other workpieces or parts.

In the peening stage of the present invention, the power component restraining device of Patent Document 1 can be used, and the entire disclosure of Patent Document 1 is incorporated herein by reference.
Media blasting or peening is used to increase the fatigue strength of gears, workpieces and parts. Gears, such as those used in automobile transmissions, are more durable by blasting media and can properly perform the desired function of the gear. The media blasting stage of the present invention includes a plurality of stages disclosed in Patent Document 2, and the disclosure of the second patent document is incorporated herein by reference.
A workpiece such as a gear is placed in a sealed chamber and the blast system is activated to mix the media with air and, after mixing, the air / media mixture is directed to the workpiece. This process is called peening.

US Pat. No. 5,272,897 US Pat. No. 6,612,909

  An object of the present invention is to perform vibration finishing after reinforcing the root radius and tooth surface of a gear by peening the gear. In the peening stage, the gear is strengthened and the tooth surface is given roughness. With the finish after peening, the tooth surfaces are smoothed, leaving small indentations or indentations. These small indentations or indentations help to retain oil on the tooth surface. The surface treatment Ra is dropped to a lower Ra (5-25 Ra) by vibration treatment after peening, but this Ra value is economical for parts with moderate or higher volume. It is impossible to reduce the surface Ra to 1 Ra or less by super finishing or similar processing. “Ra” is an international roughness standard. See, for example, Standard 4287 of ISO (International Organization for Standardization).

An object of the present invention is to provide a metal workpiece processing method. This processing method includes a step of blasting a first medium (for example, a cut wire) with respect to an exposed surface of a workpiece (for example, a gear) to increase the tooth root strength of the gear, and after finishing the first medium blast, a second medium (For example, any one of glass grains, ceramic grains, and fine steel ^TM grains) is blasted toward the exposed surface of the workpiece, and high surface compressive stress (kg / cm ² ) (KSI) is applied to the tooth surface and the root. Adding, preparing a container (e.g. a bowl), loading a fine finishing medium (wet or dry) into the container together with the workpiece, transmitting vibrations to the container, vibrating the finishing medium and the workpiece A step of removing the workpiece from the container; a step of cleaning the workpiece; and rinsing the workpiece with a rust inhibitor to increase the wear resistance of the workpiece. The medium blasting of the gear according to the present invention achieves an important objective of strengthening the root radius and tooth surface of the gear. In the present invention, toughness is described in terms of “KSI” (kilopond per square inch) (approximately 70 kg / cm ² ) or 1000 psi. KSI is often used in materials science, civil engineering and mechanical engineering to specify stress and Young's modulus.

Another object of the present invention is to subject the workpiece (eg gears, shafts, other metal parts) to media blasting and then processing (precision finishing) to give a finish, vibration or superfinishing step of about 5-25 Ra. It is to provide a workpiece having a much higher KSI on the surface than by this kind of treatment.
Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 is a front view of a workpiece processing medium blasting apparatus according to the present invention. FIG. The right view of the medium blasting apparatus for workpiece processing by this invention. 1 is a plan view of a workpiece processing medium blasting apparatus according to the present invention. FIG. FIG. 3 is a partially enlarged side view of a blasting station of a workpiece processing medium blasting apparatus according to the present invention. 1 is a cross-sectional view of a container or bowl for immersing a workpiece (eg, a gear) in a workpiece finishing superfinishing medium according to the present invention. The partial top view of the bowl 200 which put the ceramic medium and the gearwheel before closing a bowl at the time of a vibration stage. 1 is a plan view of a container or bowl for transmitting vibrations to a workpiece while the workpiece (eg, a gear) is wetted with a workpiece finishing superfinishing medium according to the present invention. FIG. 3 is a side view of a bowl or container according to the present invention. FIG. 3 is a plan view of three bowls in a production facility according to the present invention. FIG. 3 is a side view of three bowls in a production facility according to the present invention.

  Referring to the drawings, FIG. 1 shows a media blasting apparatus according to the present invention in a front view, generally designated 10. As shown, media blasting apparatus 10 includes a blasting cabinet or chamber 15 in which media flow is directed to a workpiece. This medium can include, for example, any of cut wires, glass grains, ceramic grains, and fine steel grains. The cabinet 15 is coupled to a medium hopper 25 that collects the medium that falls after colliding with the workpiece 20. Falling media includes recycled media debris, but also includes unused media, ie, media that has not been damaged. Conduit 30 connects cabinet media hopper 25 to a media collection system, generally designated 35. As best seen in FIG. 2, the cabinet media hopper 25 is also connected to an air supply device 40. The air supply device 40 supplies an air flow to the media hopper 25 to force the collected and falling media to rise through the conduit 30 to the media recovery system 35.

  As shown in FIGS. 1 and 2, the medium recovery system 35 includes a conduit 45 for sending the collected medium to the sorting device 50. The sorter 50 is a two-deck system that includes a top screen 55 and a bottom screen 60. In a preferred embodiment of the invention, the top screen is about 7.4 to 14.8 μm (20 to 40 mesh) gauge and the bottom screen is about 62.9 to 74.0 μm (170 to 200 mesh) gauge. is there. The sorting device 50 normally sorts the falling medium into non-damaged media, broken media large enough to be reused for blasting operations, and fine debris or dust that cannot be reused. The sorting screens 55 and 60 are constantly vibrated to increase sorting efficiency.

  The media recovery system 35 also includes a conduit 65. Conduit 65 is connected to filter system 70 and blower motor system 75. In one preferred embodiment, the blower motor system 75 includes a blower muffler 77 for noise reduction. The blower motor system 75 draws air from the conduit 65 and creates an ascending air flow in the conduit 45, which causes fine and non-reusable media to flow from the sorting device 50 via the conduit 45 to the conduit 65 and Transported to filter system 70. The filter system 70 is connected to a dust collector 80 that collects fine media and damaged media. Fine / broken media is collected in drum 85, which is periodically removed and emptied. In one preferred embodiment, the drum 85 is provided with rolling means and can be, for example, castered.

As shown in FIG. 1, the sorting device 50 is connected to a double pressure chamber 90 via a conduit 95. A media passage is formed between the cabinet media hopper 25 and the pressure chamber 90. In one preferred embodiment, the dual pressure chamber is maintained at about 70 to 80 psi (4.9 to 5.6 kg / cm ² ). The recovered reusable medium is sent via conduit 95 to dual pressure chamber 90 where it is mixed with unused medium. In one preferred embodiment, the size of the recovery medium is greater than 37.0 μm (100 mesh) and the unused medium is about 22.2-37.0 μm (60-100 mesh), preferably about 22. 2 to 29.6 μm (60 to 80 mesh). As described above, in the present invention, the medium may be a glass grain, a ceramic grain, or a fine steel grain. The unused medium is supplied to the double pressure chamber 90 through a plurality of medium supply valves 97. The dual pressure chamber 90 is also connected to a media sensor monitor 100 that automatically controls the supply of unused media. Appropriate peening of the workpiece is ensured by the supply control of the unused medium. In particular, the supply control of the unused medium applies an appropriate compressive stress to the workpiece 20, and a sufficiently high fatigue strength is obtained.

The dual pressure chamber 90 also preferably includes an automatic media metering on / off valve 105. The on-off valve 105 regulates the supply of the unused medium / recirculation medium mixture to the air / medium mixing point where the medium floats in the air. An automatic air valve 110 is connected to the double pressure chamber 90 so that the medium floats in the air at the air / medium mixing point and the suspended medium is sent to the blast cabinet 15 via the blast hose 115.
In the automatic medium metering on / off valve 105 of the present invention, the control of the medium flow rate is improved, and the supply of the medium and air can be controlled separately. With the automatic media metering valve 105 of the present invention, media supply is enabled by the use of a pressurized blast system rather than a suction system. In the case of a suction-type system, the suction force depends on sucking the medium from the medium supply unit into the suction gun via the medium supply hose. However, placing the metering valve 105 in the suction system will reduce the pressure drop in the media supply hose and reduce the suction force. If the suction force decreases, the supply of the medium is also disturbed. On the other hand, since the system of the present invention is a pressure drive system, the medium can be forcibly supplied to the medium mixing portion via the medium metering on / off valve 105 depending on the positive pressure.

  Another advantage of the pressurization system is that it helps to ensure proper media speed. As already mentioned, the media speed is an important control parameter for ensuring that the workpiece 20 is sufficiently compressive stressed. The pressurization system helps to ensure proper media speed by controlling the media flow rate and positioning the air / medium mixing location. The medium flow rate is controlled by a medium metering on / off valve 105. The air / medium mixing location is located sufficiently away from the blast hose to allow time for the media to reach the target speed or an appropriate speed.

  Next, the blast station 120 in the blast cabinet 15 will be described. As shown in FIG. 4, a workpiece to be processed, that is, a workpiece 20 blasted with a medium, is attached to the component holder 125. The component holder 125 is preferably cured. The workpiece 20 is held at a predetermined position by the power-type pressing device 130. In the present invention, the power-type pressing device 130 is preferably described in Patent Document 1, and it is desired to obtain a reference to the document again. The contents of this document are incorporated herein by reference. Patent powered restraining device 130 provides a cushioned variable and compensating clamp that holds the workpiece in place during media blasting. The apparatus described in Patent Document 1 is extremely important in facilitating the processing of parts having a large volume. This is particularly important for parts such as gears that tend to rotate during peening. This is because the restraining device prevents free rotation of the parts. The hold-down device can also be controlled to rotate the part at the target rotational speed. The power restraining device 130 is rotated via a rotatable shaft 135.

  A steel hardening rod 140 provides a support system for the gun-rack assembly 145. The gun-rack assembly 145 holds the nozzle holder 150. The blast nozzle 155 to which the blast hose 115 is connected is attached to the nozzle holder 150. The blast nozzle 155 directs the flow of medium suspended in the air toward the workpiece surface. Preferably, the blast nozzle is positioned about 4 to 8 inches from the workpiece 20. Although only one blast nozzle 155 is shown in FIG. 4, those skilled in the art will appreciate that multiple blast nozzles can be used. In one preferred embodiment of the present invention, as seen in FIG. 3, four blast nozzles 155 are arranged in the blast cabinet 15. The blast cabinet 15 containing the component pressing device 130 and the blasting device is provided with a door 160 for loading a new workpiece 20.

  Next, the operation of the media blasting apparatus will be described. After loading the workpiece 20 into the component restraining device 130, the door 160 is closed. A flow of media suspended in the air is then directed to the workpiece 20 by the blast nozzle 155. While the media is blasted, the workpiece is controllably rotated by the patented power component hold-down device 130. This controllable rotation ensures an even peening of the surface of the workpiece 20 and eliminates the use of a highly directional medium flow and thus the use of a water-supported medium.

  The powered component restraining device 130 preferably rotates at 8-12 rpm. However, rotation speeds of 10-12 rpm were found to be particularly effective for gear processing. This rotational speed can be related to the required degree of peening and the flatness of the resulting surface depression. Controlled low speed rotation enables even peening with uniform small indentations and prevents the formation of indentations resulting from non-uniform impingement of media flow on the surface. These indentations can act as precursor forms of cracks. If the workpiece is a gear, controlled rotation ensures that any medium, such as cut wire, ceramic grain, fine steel grain, or glass grain, is directed to the gear root and tooth surface during the course of rotation. . By ensuring uniform peening, the work characteristics of the workpiece 20 are improved.

  In one embodiment, a relatively small amount of media stream is blasted faster and for a longer time than with prior art methods. The preferred flow rate depends on the type and size of the medium used, as well as on the particular application involved. In the case of gear processing, medium flow rates of about 0.68 to 1.35 kg / min (about 1.5 to 3 lb / min) have been found to be efficient. Of course, other flow rates could be used depending on the desired performance. This flow rate has been found to be efficient for glass media, ceramic media, fine steel media in the size range of about 18.5-37.0 μm (50-100 mesh). However, in a preferred embodiment of the present invention, a glass medium of about 22.2-37.0 μm (60-100 mesh) is used. When glass media of about 22.2-37.0 μm (60-100 mesh) is used to process certain gears, including gears made using 8620 steel, there is a significant improvement in the working characteristics of the gears. It was. The choice of media to use depends on the application and relative economics. Ceramic and steel media last longer than glass, but are more expensive.

After the media collides with the workpiece 20, it falls into the cabinet media hopper 25 and is carried to the collection system 35. The reusable media is separated from the fine media and dust, mixed with the unused media, and then returned to the blast station 120. This mixing reduces media waste. By reusing the partially damaged media, the media polishing effect on the workpiece 20 is also improved.
Satisfactory results can be obtained by using glass media for blasting of certain gears including gears made of certain materials such as 8620 steel, but in the case of gears made of other materials such as 5130 m steel, It has been found that the use of glass media is completely undesirable. In general, the blasting with ceramic media of the present invention has been found to be effective for a wide variety of gears made of various metals. Several oxide ceramics such as ZrO ₂ , AL ₂ O ₃ , SiO ₂ , MgO, etc. can be used for blasting. Preferred media include crystalline zirconia uniformly encased in a quartz glass phase. The medium is sold under the trade names ZIRBLAST ^™ and ZIRSHOT ^™ by SEPR, located in Le Défense, Paris.

Surprisingly, it has been found that blasting using ceramic media gives significantly better results for certain metal gears than with glass blasting. For example, as compared with the conventional method, the resistance to pitting on the surface of the gear is improved, and the strength of the root radius is improved. For the gear, when not in use, ceramic media from about 14.8-37.0 μm (40-100 mesh), flow rate of about 0.454-11.35 kg / min (1-25 pounds per minute), 15-15 180 second cycle time, 2.45 to 6.3 kg / cm ² (35 to 90 psi) pressure, about 5 to 25 rpm gear rotation speed, 15 to 28 N Almen strength, effective for gear processing It turned out to be. In the case of the gear, excellent results were observed under the following processing conditions. That is, a small flow rate of about 0.454 to 1.36 kg / min (1 to 3 pounds per minute), a pressure of about 4.9 to 5.6 kg / cm ² (70 to 80 psi), a cycle of 15 to 120 seconds. Time, rotational speed of about 8-12 rpm, media diameter of about 0.210-0.150 mm.

  Because ceramic media is relatively expensive, it can be collected after blasting the gear, added to the unused media and recirculated, and after the initial start-up of the system, the mixture of unused and reused media is reused. preferable. In this preferred process, a screen of about 62.9-74.0 μm (170-200 mesh) is used as the bottom screen of the media recovery system sorter to remove small pieces of media from the recycled media mixture.

In yet another embodiment of the present invention, a method for treating a metal gear with a fine metal media blast flow is described using the apparatus described above. This preferred method has a media flow rate of about 0.454 to 1.8 kg / min (about 1 to 4 pounds per minute), a media diameter of about 150 to 200 micrometers, about 4.9 to 5.6 kg / cm ² ( At a pressure of about 70-80 psi) and an almen range of about 18-26 N. The fine steel medium is preferably collected after gear blasting and recirculated.

  Steel grain shot media lasts significantly longer than ceramic or glass, so very little unused media needs to be added to the media blasting equipment. As a result, the need for monitoring and maintenance is significantly reduced and the amount of media used for good mass processing of gears is also reduced. Metal gears treated in this way typically have fewer and less obvious indentations remaining in the surface texture than the media blast treatment with glass or ceramic media disclosed herein. In addition, the gears treated in this way have a lower fatigue strength than the treatment with glass or ceramic media disclosed herein. However, in dynamometer testing, the fine-grained media has been in continuous use up to failure for more than 70 hours, which is significantly greater than the expected failure performance for coated gear processing for 40 hours. Due to maintenance, monitoring, and media costs, the processing with the fine grain media disclosed herein is a low cost method that provides superior performance over conventional shot peening. Peening with a fine steel ball medium is a method that works well for many gears with high surface pitting resistance. Blasting with a ceramic medium is preferred when high pitting is shown during a gear test with a dynamometer.

  When the ceramic blasting apparatus described here is used, the gears are processed in a double peening stage as follows. The exposed surface of the gear is blasted with a first medium (for example, a cut wire). The tooth base of the gear is further strengthened by the blasting step (peening) in the first medium. After medium blasting with the first medium, the gear is blasted on the exposed surface with the second medium (glass grains, ceramic grains, steel grains). During the media blasting (peening) with the second media, the gear surface is strengthened, leaving some roughness on the surface. This rough surface indentation or indentation is the result of blasting, for example with media of about 150-200 micrometers. Indentations or indentations resulting from blasting are less than 150 micrometers, usually less than 75 micrometers. These small indentations provide high compressive stress and easily shift oil retention on the gear surface during gear use. Subsequent finishing operations reduce the size of the indentation or indentation, but retain the advantages of gear surface compression stress and oil retention.

  After double peening, the gear 201 is fed to a bowl 200 containing a wet or dry precision finishing medium 212. The precision finishing medium 212 is preferably a wet acidic medium. Bowl 200 is shown in FIG. 5 (gear 201 is placed in precision finishing medium 212, but not shown in FIG. 5). The bowl 200 has an outlet 202, an inlet 204, a side wall 206, a top 208 and a bottom 210. Wet acidic precision finish media 212 is provided in an amount sufficient to wet the gear and ceramic media. FIG. 6 is a partial view of bowl 200 containing ceramic media 212 and gear 201 prior to closing the bowl for the vibration phase. The relative dimension between the gear 201 and the ceramic medium 212 shown is merely an example of the relative dimension between the gear 201 and the ceramic medium 212. Typically, the ceramic media is smaller than that shown in FIG. That is, the relative dimensions of the ceramic medium 212 and the gear 201 are sufficiently small so that the medium 212 can enter between the gear teeth, so that the gear surface between the teeth is precisely finished during the precision finishing operation (vibration). . The vibration of the bowl 200 is transmitted to the bowl 200 via the vibration coupler 214.

  An example of a precision finishing medium 212 is a mixture of a ceramic medium and a weakly acidic solution. FIG. 7 shows a part of a production facility having three bowls with lids. 8 to 10 show the bowl in the production facility. Each bowl is supported on the floor via three springs (more or less). As seen in FIG. 7, the three bowls 200 are covered with a lid for soundproofing and the like. The bowl 200 is usually made of steel and has a polyurethane liner for transmitting vibration to the medium. For example, as seen in FIG. 6, a channel 250 extends inside the bowl 200 over the entire inner periphery of the bowl 200. The center portion of the bowl has a cylindrical shape having an outer peripheral wall 400 (see a cylindrical outer wall denoted by reference numeral 300 in FIG. 6), and the outer peripheral wall 400 is separated from the cylindrical wall 300 by a channel 250.

  A side opening of the bowl 200 is provided with a removable opening with a lid so that the contents can be taken out. Since the inside of the channel 250 is beveled, the contents flow in a circle along the channel when vibration is transmitted to the bowl. Other shapes can be applied to the channel wall or floor to move the contents in a circle. This movement advances the mixing of the contents, thereby exposing any surface of the gear to the smoothing action of the media 212 within the channel 250.

  In one preferred embodiment, the gear is wetted by the precision finishing medium in the bowl, vibrations are transmitted to the bowl, and the superfinishing medium vibrates along with the internal gear. The vibration continues for a time sufficient for the gear to be finished to about 5-25 Ra. During vibration (fine finishing), additional water and / or fine finishing media is added via one or more inlets 204. Excess precision finishing media, water, etc. are removed through outlet 202. The precision finishing is continued until the gear surface (workpiece) is smoothed, but dents and indentations are left sufficiently to increase the oil retention rate on the gear surface. A finish with Ra of zero is undesirable. This is because such a perfectly smooth finish does not leave surface indentations, indentations, etc. that enhance oil retention.

  It is believed that the indentation provides a place to collect oil and retain oil during gear operation, so that a certain amount of lubricating oil is combined with the smoothness of the gear, increasing the service life of the gear. After the double peening as described above, it was found that the life of the gears was significantly increased by precision finishing to a target range of about 5 to 25 Ra. After precision finishing, the gear is removed from the bowl, cleaned and rinsed. The gears are rusted at the final stage, thereby enhancing the wear resistance.

  In another embodiment, the gear is precision finished in the bowl without the addition of a liquid medium (ie dry precision finishing medium). In this embodiment, the gear is virtually precision finished dry with a wear material that smoothes the gear surface, but the wear material is not liquid. By transmitting vibrations to the container and vibrating the precision finish medium with the gear, the size of the indentation on the gear surface is reduced, but the advantages of compressive stress and oil retention remain. The finished surface is smooth as described above, and dents due to peening are reduced after finishing but remaining.

Results of the medium peening, at least about 5,631kg ^/ cm 2 to dedendum circle radius of the gear (80 KSI), the residual compressive stress of at least about 5,631kg ^/ cm 2 (80KSI) is obtained on the gear surface. The residual compressive stress at a depth of 0.0127 mm (0.0005 in), 0.0245 mm (0.001 in), and 0.49 mm (0.002 in) is usually at least about 7,038 kg / cm ² (100 KSI). is there. Using the above processing parameters, the gear has a residual compressive stress of at least 7038 kg / cm ² (100 KSI) for the root radius and at least 0.000 mm (0.000 in) for the normal depth (surface). about ^{9,150kg / cm 2 (130KSI),} 0.0127mm in (0.0005in) about ^{12,250kg / cm 2 (175KSI),} 0.0245mm (0.001in) in about 14,000kg ^/ cm 2 (200KSI) , 0.49 mm (0.020 in) was manufactured to be about 15,750 kg / cm ² (225 KSI).

In the case of gears processed by the previously described two-stage media blasting method, subsequent precision finishing tests confirmed that the gears had superior performance compared to gears that were not processed by this three-stage machining. It has been found that the gears treated by this preferred machining method have excellent fatigue strength and operate satisfactorily with little evidence of wear during testing over hundreds of hours. On the other hand, the gear processed by the conventional method can be expected to break in about 20 hours during the dynamometer test.
Although the method of media blasting for gears has been disclosed herein in connection with a restraining device, other conventional component holders and blasting devices can be used with the multiple stages described herein. It will be appreciated that the described process very often requires gear peening at the tooth base to prevent fatigue bending at the tooth root radius. In the present disclosure, it has been recognized that sometimes the first peening step is not necessary and only peening with ceramic or glass grains is required. In the latter case, the stress applied to the gear is smaller and is expected to probably shorten its life.

  Applicants have now described specific embodiments of the invention and illustrated the drawings, which are not intended to limit the invention. While the applicant has described various aspects of the invention in specific embodiments, various alternative forms and modifications can be made to the present disclosure without departing from the spirit and scope of the invention as defined in the claims. It will be understood that this is possible.

Claims (16)

In a method of machining a metal gear,
Obtaining a gear,
Directing the first peening medium to the metal gear and exposing the plurality of surfaces of the gear to the first peening medium to increase the strength and wear characteristics of the gear teeth;
Increasing the compression stress (KSI) of the gear surface by directing the second peening medium to the metal gear and exposing a plurality of surfaces of the gear to the second peening medium;
Obtaining a container;
Placing the precision finishing medium in the container;
Loading the gear with the precision finishing medium into the container; transmitting the vibration to the container so that the precision finishing medium vibrates with the gear;
Removing the gear from the container;
Cleaning the gears;
A method of machining a metal gear, comprising rinsing the gear with a rust inhibitor.   The method of claim 1, wherein the precision finishing medium comprises zinc tip, water, and aluminum oxide powder.   The method of claim 1, wherein the container is a steel bowl lined with polyurethane.   The method of claim 1, wherein the vibration is continued for a time sufficient to finish the gear to about 5-25 Ra.   The method of claim 1, wherein the first peening medium comprises a cut wire.   The method of claim 1, wherein the second peening medium comprises one of glass grains, ceramic grains, and fine steel grains.   The method of claim 6, wherein the peening medium has a diameter of less than about 250 micrometers. The first peening medium includes a ceramic medium, the ceramic medium is directed to the metal gear at a pressure of about 1.75 to about 6.3 kg / cm ² (about 25 to about 90 pounds per square inch), and the ceramic medium The method of claim 1, wherein the medium has a diameter of about 0.210 mm to about 0.150 mm when added as a fresh medium. In the product,
A product produced by the method of claim 1.   The method of claim 1, wherein the precision finishing medium comprises an acidic medium.   The method of claim 1, wherein the precision finishing media comprises a dry media.   The method of claim 1, wherein the first peening medium is directed to the metal gear to provide an indentation on the gear surface, increasing the compressive stress on the gear surface, and facilitating oil retention by the indentation.   13. The method of claim 12, wherein vibrations are transmitted to the container to vibrate the precision finish medium with the gear, thereby reducing the indentation size of the gear surface while leaving the compressive stress and oil retention benefits on the gear surface. In metal gear machining equipment,
An apparatus for directing the first peening medium to the metal gear such that a plurality of surfaces of the metal gear are exposed to the first peening medium in order to increase the tooth root strength and wear resistance of the gear;
An apparatus for directing the second peening medium to the metal gear such that multiple surfaces of the gear are exposed to the second peening medium to increase the compressive stress (KSI) of the gear surface;
A container,
Precision finishing media in the container;
An apparatus for placing a gear exposed to the first peening medium and the second peening medium into the container;
A device that transmits vibration to the container to vibrate the precision finishing medium with the gear;
A device for removing the gear from the container;
A device for cleaning the gears;
Metal gear processing equipment, including equipment for rinsing gears with rust inhibitor. In metal gears,
A metal gear manufactured by the metal gear machining apparatus according to claim 14. In metal gears,
The surface of the metal gear is treated with a first peening medium to increase the gear tooth root strength and wear resistance, and is treated with a second peening medium to increase the compression stress (KSI) of the gear surface; Further, a metal gear that is precision finished by vibrating with a precision finish medium, resulting in a precision finish surface formed by peening and having reduced indentation.

Images