AGMA - American Gear Manufacturers Association

AGMA 2001-D04

Fri, 01 Jan 2010 00:00:00 GMT

AGMA 2001-D04; Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth AGMA - American Gear Manufacturers Association Rating formulas
This standard provides a method by which different gear designs can be theoretically rated and compared. It is not intended to assure the performance of assembled gear drive systems.
These fundamental rating formulas are applicable for rating the pitting resistance and bending strength of internal and external spur and helical involute gear teeth operating on parallel axes. The formulas evaluate gear tooth capacity as influenced by the major factors which affect gear tooth pitting and gear tooth fracture at the fillet radius.
The knowledge and judgment required to evaluate the various rating factors come from years of accumulated experience in designing, manufacturing, and operating gear units. Empirical factors given in this standard are general in nature. AGMA application standards may use other empirical factors that are more closely suited to the particular field of application. This standard is intended for use by the experienced gear designer, capable of selecting reasonable values for the factors. It is not intended for use by the engineering public at large.
Exceptions
The formulas of this standard are not applicable to other types of gear tooth deterioration such as plastic yielding, wear, case crushing and welding. They are also not applicable when vibratory conditions exceed the limits specified for the normal operation of the gears (see ANSI/AGMA 6000-A88, Specification for Measurement of Lateral Vibration on Gear Units).
The formulas of this standard are not applicable when any of the following conditions exist:
- Damaged gear teeth.
- Spur gears with transverse contact ratio, mp, less than 1.0.
- Spur or helical gears with transverse contact ratio, mp, greater than 2.0.
- Interference exists between tips of teeth and root fillets.
Teeth are pointed.
- Backlash is zero.
- Undercut exists in an area above the theoretical start of active profile. The effect of this under-cut is to move the highest point of single tooth contact, negating the assumption of this calculation method. However, the reduction in tooth root thickness due to protuberance below the active profile is handled correctly by this method.
The root profiles are stepped or irregular. The J factor calculation uses the stress correction factors developed by Dolan and Broghamer. These factors may not be valid for root forms which are not smooth curves. For root profiles which are stepped or irregular, other stress correction factors may be more appropriate.
- Where root fillets of the gear teeth are produced by a process other than generating.
The helix angle at the standard (reference) diameter(Footnote *) is greater than 50 degrees.
Scuffing criteria are not included in this standard. A method to evaluate scuffing risk can be found in AGMA 925-A03. This information is provided for evaluation by users of this standard, with the intent to include a scuffing evaluation method in a future version of this standard.
Design considerations to prevent fractures emanating from stress risers on the tooth profile, tip chipping, and failures of the gear blank through the web or hub should be analyzed by general machine design methods.
Footnote * - Refer to ANSI/AGMA 1012-F90 for further discussion of standard (reference) diameters.

AGMA 6025-D98

Fri, 01 Jan 2010 00:00:00 GMT

AGMA 6025-D98; Sound for Enclosed Helical, Herringbone and Spiral Bevel Gear Drives AGMA - American Gear Manufacturers Association This standard describes the instrumentation, measuring methods and test procedures necessary for the determination of a gear unit's sound pressure levels for acceptance testing. Sound power measurement methods are provided in annexes A, B and C for use when required by specific contract provisions between the manufacturer and purchaser.
Application
This standard is applicable to gear drives designed and rated in accordance with the following standards: ANSI/AGMA 6010-F97, Standard for Spur, Helical, Herringbone and Spiral Bevel Enclosed Drives; ANSI/AGMA 6011-H97, Practice for High Speed Helical and Herringbone Gear Units; ANSI/AGMA 6019-B89, Standard for Gearmotors Using Spur, Helical, Herringbone, Straight Bevel or Spiral Bevel Gears; and ANSI/AGMA 6021-G89, Standard for Shaft Mounted and Screw Conveyor Drives Using Spur, Helical and Herringbone Gears.
ANSI/AGMA 6025-D98 applies to only those gear units which are lubricated in accordance with manufacturer's recommendations and tested in a system of connected rotating parts free from serious critical speeds, torsional vibrations or overloads as tested at the gear unit manufacturer's facility.
Where performance of actual shop tests to determine sound level is required, it shall be the responsibility of the purchaser to so state in his inquiry and order.
NOTE: The gear unit is only part of the total acoustic system which includes, in addition to the gear unit, the prime mover, driven equipment, gear unit mounting, foundation and acoustic environment. Each of these might affect the measured level of sound emitted from the gear unit. Unless otherwise agreed, the gear manufacturer's responsibility is to ensure that the level of noise emitted from a gear unit under the test conditions in his factory is within contractually specified or negotiated limits.
Special contractual considerations are discussed in annex D.
CAUTION: Compliance with this standard does not constitute a warranty of the measured gear unit sound levels under installed field service conditions.

AGMA 9005-E02

Tue, 01 Jan 2008 00:00:00 GMT

AGMA 9005-E02; Industrial Gear Lubrication AGMA - American Gear Manufacturers Association This standard provides the end user, original equipment builder, gear manufacturer, and lubricant supplier with guidelines for minimum performance characteristics for lubricants suitable for use in general power transmission applications. These guidelines cover both open and enclosed gearing which have been designed and rated in accordance with applicable AGMA standards. The types of gearing included herein are metallic spur, helical including herringbone, straight and spiral bevel, and worm. These guidelines may or may not be applicable to non-metallic gears.
This standard does not address grease lubricated enclosed drives, aerospace applications or address special regulatory requirements associated with food or drug handling or manufacturing equipment. This standard is not intended to replace any existing standards such as in automotive applications where similar gearing may be used.
NOTE: This standard is not intended to supplant any specific recommendations of gear manufacturers.

AGMA 9000-D11

Sat, 01 Jan 2011 00:00:00 GMT

AGMA 9000-D11; Flexible Couplings - Potential Unbalance Classification AGMA - American Gear Manufacturers Association This standard defines classes of flexible coupling potential unbalance, one of which the user must select in order to meet the needs of their system. The classes are established using weight and speed and system sensitivity to arrive at a mass displacement value that defines the potential unbalance. The standard defines types of unbalance, provides a method of selecting balance class, identifies contributors to potential unbalance, and provides a method of determining potential coupling unbalance. The balance classes are derived from consideration of the potential unbalance of the coupling.
The balancing requirements for a flexible coupling depend upon the rotating system into which it is mounted. Each half of the coupling is mounted on a separate rotor with the whole coupling providing the connection. Each of the connected rotors is balanced independently of the coupling and the coupling is added when the rotors are installed.
This standard is used with ANSI S2.19-1999 or ISO 1940-1:2003 which apply to balance quality requirements of rigid rotors. If ANSI S2.19-1999 or ISO 1940-1:2003 is used for balancing coupling components and assemblies in the balancing machine, then potential unbalances are introduced after the coupling is disassembled and reassembled either in the balancing machine or the rotor system. These potential unbalances are primarily the result of:
- balancing mounting fixture inaccuracies;
- displacement of coupling components with respect to the axis of rotation of the rotor system during disassembly and reassembly of the coupling.
Application
This standard is applicable to couplings and addresses potential unbalance which could be expected of a coupling in service. This standard accounts for issues of runout and clearances in the calculation of potential unbalance and resulting balance class. It should be noted that a flexible coupling is generally an assembly of several components having diametral clearance and eccentricities between the pilot surfaces. ANSI S2.19-1999 (ISO 1940-1:2003) addresses residual unbalance as measured in the balancing machine.
Exclusions
This standard does not take into account arbitrary balance standards developed by other standards organizations (e.g., American Petroleum Institute). In addition, this standard does not address the unbalance effects caused by:
- shaft runout;
- keys that protrude beyond the hub or shaft;
- unfilled keyways or keyseats;
- coupling mounting surface clearance;
- non-homogeneous materials;
- curved datum.
Additional considerations
Balancing a coupling does not assure one of great gains in balance. The greatest gains in balance comeduring themanufacturing of the coupling. Controlled runouts of pilots and pilot fit clearances, provided by the coupling supplier during manufacturing, give the greatest results. Balancing of various components results in minimal gain over controlling the bore runout during re-boring. It should be noted that two perfectly balanced parts mounted eccentrically would still shake. An assembly balanced coupling, re-assembled to runouts different than those when in the balance machine, will still be out of balance (the difference between residual and potential unbalance).
Calculations of system unbalance cannot be used to determine system vibrations as stated in the introduction to ISO 1940-1:1986 and ANSI S2.19-1999, which reads:
"It is not readily possible to draw conclusions as to the permissible residual unbalances from any existing recommendations on the assessment of the vibratory state of machinery, since there is often no easily recognizable relation between the rotor unbalance and themachine vibrations under operating conditions. The amplitude of the once-per-revolution vibrations is influenced by characteristics of the rotor, of themachine, of the structure and of the foundation, and by the proximity of the service speed to the various resonance frequencies, etc. Moreover, the machine vibrations may be due only in part to the presence of rotor unbalance."