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Characterization and Manufacture of Bevel gear

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Characterization and Manufacture of Bevel gear

Characterization and Manufacture of Bevel gear

thunderspeed

(Mechanical)

(OP)

2 Nov 15 16:11
I have bevel gear that works on ring gear (pinion and ring) simillar to the one in the following picture :


I want to charachterize the small bevel gear (pinion) to give the measurements to a workshop to manufacture copies for this gear or buy it.
Also I'd like to take an idea about the method of manufacturing those in workshop .

thanks in advance

Hi all ,I have bevel gear that works on ring gear (pinion and ring) simillar to the one in the following picture :I want to charachterize the small bevel gear (pinion) to give the measurements to a workshop to manufacture copies for this gear or buy it.Also I'd like to take an idea about the method of manufacturing those in workshop .thanks in advance

RE: Characterization and Manufacture of Bevel gear

tbuelna

(Aerospace)

Contact us to discuss your requirements of Straight Bevel Gear. Our experienced sales team can help you identify the options that best suit your needs.

4 Nov 15 00:25

Based on your OP, it appears you do not have much experience with gear engineering and manufacturing. So I would strongly recommend hiring an experienced consultant to assist with this effort. The consultant will know where to get the gear measured/analyzed, he will prepare all the engineering documentation required, he will specify the correct material/heat treatment/processing/QA required, he will help you prepare your purchase specification, and he will help you select a qualified vendor. It will cost a bit of money to hire a gear expert, but it is money well spent. Most importantly, the gear expert will make sure the gear is engineered to give the best combination of cost, quality and performance for your particular application. Trying to do this job on your own without having much prior experience will likely not end well.

In your particular case, I would also not recommend simply relying on a single vendor to both reverse engineer and manufacture the pinion. With your limited technical knowledge of gears, you would not be able to prepare a purchase specification with the necessary level of detail to ensure the product delivered is exactly what you require. Without a detailed purchase specification, you would be forced to accept whatever the vendor decides to deliver. Caveat emptor, right?

One additional benefit to hiring a consultant to do this work is that you will get first-hand experience doing this job properly from start to finish.

Best of luck to you.
Terry

RE: Characterization and Manufacture of Bevel gear

thunderspeed

(Mechanical)

(OP)

4 Nov 15 08:09

I understand that this job needs someone experienced to handle it .The old gears have been sent to a specialized workshop to make identical copies .Financial resources are very limited where I work.What I'm asking about is the methodology and measurements I would take either to accept the manufactured or purchased bevel . And in the future , what measurements and characteristics of the bevel gear I should send the manufacturer to order one without the need to send the old gear .

RE: Characterization and Manufacture of Bevel gear

mfgenggear

(Aerospace)

4 Nov 15 18:25

thunderspeed

I do not have experience with this size of a beveled gear set. far as handling and tooling.
but Terry did answer the question. have the supplier who is making the gear" pay them" to get the reverse engineering.
all of the dimensional attributes, eg outside diameters, inside diameters, all the lengths, an on.
the gear data is very important. in order to know the material and heat treat characteristics there will have to be a met lab analysis. is it induction harden, through harden, case harden etc. if they are not qualified to do this then find someone who is. that have both metallurgical & mechanical gear engineering expertise.

have them put this on a blue print.

Mfgenggear

RE: Characterization and Manufacture of Bevel gear

tbuelna

(Aerospace)

6 Nov 15 02:32

thunderspeed- I fully appreciate the position you are in with regards to budget constraints and limited expertise with gear engineering/manufacturing. And the recommendations I provided above took your situation into consideration.

"I understand that this job needs someone experienced to handle it .The old gears have been sent to a specialized workshop to make identical copies .Financial resources are very limited where I work."

To get the gear reverse engineered you will need to pay someone to perform this work. You chose to rely on the gear vendor to perform this task, but I gave you several reasons why it would be better for you to hire a consultant instead.

"What I'm asking about is the methodology and measurements I would take either to accept the manufactured or purchased bevel."

As I noted above, the acceptance requirements for your pinion should be explicitly defined on the purchase contract. The preparation of your purchase contract will require a thorough knowledge of every aspect of gear design and manufacture. It will also require someone with similar expertise to review the QA documentation submitted with the finished pinions to determine if they conform to the purchase contract requirements. Asking a vendor to "make identical copies" is basically meaningless. The vendor is free to determine whether the pinions delivered meet the definition of "identical copies".

"And in the future , what measurements and characteristics of the bevel gear I should send the manufacturer to order one without the need to send the old gear."

One reason I recommended hiring a gear consultant for this job was because it would allow you to experience firsthand the process required from start to finish, and it wouldn't cost anything extra.

RE: Characterization and Manufacture of Bevel gear

geesamand

(Mechanical)

2 Dec 15 20:32

I guess some basic information would help us guide you to an economical result:
1) What RPM are the input and output?
2) What diameter is the main gear?
3) What service is this bevel set?

It's important to understand that in some kinds of gearing, a complete reverse-engineering effort can yield a suitable replacement for one piece in the set. Spur and helical gearing can be reverse engineered in most cases, if you're willing to invest in enough measurement and engineering effort.

Bevel gearing is often crowned using machine settings and lapped to the pinion, meaning that without the main gear it's impossible to make a reasonable replacement pinion. Bevel gearing with spiral or curved forms are also produced with many machine settings that are not included in a drawing. So even if you were the original manufacturer, it might not be reasonable to supply a single pinion without testing it against the mating gear.

RE: Characterization and Manufacture of Bevel gear

tbuelna

(Aerospace)

8 Dec 15 06:39

geesamand-

From the photo provided it looks like those are straight bevel gears. But as you noted, due to the fairly significant ratio between the pinion and gear, and relatively wide face, you would expect there to be a fair bit of geometry modification (crown, lead compensation, tip relief, etc) applied to the tooth profiles.

With a gear set that large, I would also expect the pinion face to be wider than the gear face width, which does not seem to be the case.

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News

Spiral bevel gear drives play a critical role where motive force within a machine must be transferred “around a corner.”

Spiral bevel gearboxes are often specified in challenging locations such as washdown processing areas, or, conversely, where the end-use environment must avoid contamination from an open drive. Drives are offered by a wide variety of vendors, large and small. They’re specified and bought by design engineers and purchasing agents for original equipment manufacturers (OEMs), as well as by in-plant maintenance and repair operations (MROs).

How can these specifiers and purchasers obtain the most suitable drives for their needs? Here are five key questions to ask prospective vendors in determining whether their spiral bevel gear drives are the optimum choice for your unique application.

1. Are they suited for use in challenging environments?
Many applications require specialized drive materials, components, or designs to deliver
required performance in difficult environments. For best results, designers and purchasers should describe end-use conditions to vendors carefully. Where exactly will the drive be located? Note any possibilities of contamination, either from the environment to the drive or vice-versa. Warn of temperature extremes. Can gearing be open, or are closed housings mandated? Must any special governmental regulations or industry association standards be met? What service life is expected? What’s been the previous experience of similar drives for this use?

2. Have they been designed for field maintenance, repair, and rebuild?
Properly assembled and sized for the application, a well-made spiral bevel gear drive should last for years in all but the most difficult applications. If a drive develops trouble or fails after warranty, depending on age and condition it is often most cost-effective to purchase a new unit. However, in some cases it may still be worth considering maintenance, repair, or rebuild instead of replacement. Before you buy, ask vendors if such services are possible with their products.

3. How do they minimize noise and backlash?
Most designers and end users like their gearsets as quiet as possible. Noisy gears actually may signify mechanical deficiencies that contribute to poor performance and shortened drive life. Plus even where an unusually hushed environment is not a prime consideration, quiet gears provide a perception of high quality and superior functionality.

The type of gear you choose can depend on the gear performance you require. For lower speeds and lighter loads, straight bevel gears may be adequate, although their abrupt transfer from tooth to tooth tends to create higher impact stress and greater noise.

By contrast, spiral bevel gears are designed so that their curved teeth come into contact gradually. You get higher tooth-to-tooth contact covering a greater surface area. This allows well-made spiral bevel designs to offer smooth, quiet operation, even at high speeds and greater load capacities.

When comparing different spiral bevel designs, complex considerations determine the final amount of noise emitted by any given gearset. One prime factor: backlash. This is defined as the distance between meshing gear teeth. All else being equal, the greater the backlash, the louder the impact when gear meets gear. A critical question: can your drive vendor make the adjustments required to minimize backlash?

Most manufacturers assemble their gears to a “loose” distance. They then close the gap just enough to get minimally acceptable tolerance by locking each gear permanently into place with a shim or retaining ring. However, even a slight variation in the manufacturing process can substantially increase the backlash on an individual gearset.

One exception is the MITRPAK® spiral bevel gear design. It eliminates shims and rings. Instead, its unique adjustable locknut allows each gearset to undergo extremely precise final adjustment by hand. Result: absolutely minimal backlash and the smoothest, quietest possible operation.

4. Can they be ordered in sizes and ratings for specific applications?
Different jobs demand different drives. Look for vendors that are willing to discuss your precise application, then offer options in terms of sizes and ratings that can deliver high performance and optimized drive service life within the parameters your job generates.

Pay particular attention to suggested torque ratios. These ratings are based on revolutions per minute under a given horsepower. In an all-too-common scenario, a customer may underestimate the amount of torque a drive will routinely encounter on the job. Suppliers sometimes discover that their drives rated for 190 inch pounds of torque are instead running at 400 inch pounds! This is bad news, since each drive is rated for an ultimate static torque. If operation frequently exceeds recommended levels of torque and/or horsepower, a good drive may still operate acceptably for some time. However, eventually, teeth wear; bearings fail; roll pins fatigue, and then shear.

Make a preliminary attempt to spec your drive by consulting the vendor’s catalog or Web site. Then, especially if your requirements seem at all out of the ordinary, contact the vendor or distributor. At a minimum, a good vendor should be willing to work closely with you, ensuring that the drive and components you select match the requirements of the work you want the drive to do.

5. Can they be customized for my application?
In many cases, a spiral bevel gear drive is much more than a commodity part. It’s a complex machine that’s precisely engineered for your exact needs. If your application is at all out of the ordinary, it’s crucial to find a vendor that provides problem-solving expertise and customization. For OEMs, this helps cut costs and design time, simplifies the design and engineering process, and reduces risk. For MROs, it helps ensure greater asset availability. And for both OEMs and MROs, it improves ultimate performance and extends equipment life.

Vendors willing to undertake specialized designs can meet specific performance requirements by customizing any of the following gear drive components:
• Housings
• Gear materials
• Roll pins/dowel pins
• Plating
• Locknuts
• Seals
• Shafts
• Bearings
• Lubricants
These are just a few considerations before you order a spiral bevel gear drive. Contact us to learn more about how Lampin goes beyond precision to meet your needs.

For more Kexin Gearinformation, please contact us. We will provide professional answers.