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Papers by Alexander Kapelevich

Gear Technology, 2003

Introduction Bending stress evaluation in modern gear design is generally based on the more-than-... more Introduction Bending stress evaluation in modern gear design is generally based on the more-than-one-hundred-year-old Lewis equation. This equation, applied with the stress concentration factor Kf, defines the bending stress geometry factor J for traditionally designed standard ...

Direct Gear Design, 2013

This paper presents a unique approach and methodology to define the limits of selection for gear ... more This paper presents a unique approach and methodology to define the limits of selection for gear parameters. The area within those limits is called the "area of existence of involute gears" (Ref. 1). This paper presents the definition and construction of areas of existence of both external and internal gears. The isograms of the constant operating pressure angles, contact ratios and the maximum mesh efficiency (minimum sliding) isograms, as well as the interference isograms and other parameters are defined. An area of existence allows the location of gear pairs with certain characteristics. Its practical purpose is to define the gear pair parameters that satisfy specific performance requirements before detailed design and calculations. An area of existence of gears with asymmetric teeth is also considered.

analysis and design of spur and helical involute gears. Introduction Modern gear design is genera... more analysis and design of spur and helical involute gears. Introduction Modern gear design is generally based on standard tools. This makes gear design quite simple (almost like selecting fasteners), economical, and available for everyone, reducing tooling expenses and inventory. At the same time, it is well known that universal standard tools provide gears with less than optimum performance and— in some cases—do not allow for finding acceptable gear solutions. Application specifics, including low noise and vibration, high density of power transmission (lighter weight, smaller size) and others, require gears with nonstandard parameters. That’s why, for example, aviation gear transmissions use tool profiles with custom proportions, such as pressure angle, addendum, and whole depth. The following considerations make application of nonstandard gears suitable and cost-efficient: • CNC cutting machines and CMM gear inspection equipment make production of nonstandard gears as easy as product...

The contact ratio of spur gears is a critical parameter that affects gear drive performance. The ... more The contact ratio of spur gears is a critical parameter that affects gear drive performance. The influence of this parameter on the gear drive load capacity, efficiency, and noise and vibration is well known. There are studies (Refs. 1–3) dedicated to the analytical and experimental comparison of gears with low and high contact ratios. The dynamics and efficiency of high-contactratio asymmetric tooth gears were described in (Refs. 4–5). These publications explore contact ratio using a very similar evaluation approach. The gears are designed traditionally, based on a preselected basic (or generating) rack. This makes the contact ratio dependent on the number of teeth of mating gears, basic rack addendum, and X-shifts. A contact ratio is considered nominal, as it is designed without influence of deflections under the operating load. Comparable gear sets with different contact ratios are identical in numbers of teeth, tooth size, and modules. Such comparisons might have some theoretica...

Introduction When compared with the tradit ional gear design approach — based on pre-selected, ty... more Introduction When compared with the tradit ional gear design approach — based on pre-selected, typically standard generating rack parameters — the alternative Direct Gear Design (Ref.1) method provides certain advantages for custom, high-performance gear drives. Among them are increased load capacity; efficiency; length-of-service; reduced size and weight; noise/ vibrations; and cost. However, the manufacture of such nonstandard gears requires custom tooling and certain alterations of known gear fabrication processes. This paper presents specifics of application main methods of gear fabrication, i.e. — form and generating machining (cutting and grinding); gear forming injection molding technology; net forging; powder metal (PM) processing; die casting; and wire EDM gear prototyping. It also describes tooling profile definition, dependent upon the selected gear fabrication method. It presents the Genetic Molding Solution technique for compensation of differential warpage and shrinkag...

Journal of Mechanical Design, 2020

<jats:title>Abstract</jats:title> <jats:p>Veniamin I. Goldfarb, well-known scho... more <jats:title>Abstract</jats:title> <jats:p>Veniamin I. Goldfarb, well-known scholar and educator, passed away on November 12, 2019, at the age of 78. As Director of the Institute of Mechanics of the Izhevsk State Technical University, Professor Goldfarb was a towering figure in the field of power transmission and gearing, specializing in gear geometry, kinematics and contact mechanics.</jats:p>

The Proceedings of the JSME international conference on motion and power transmissions, 2017

Gear Technology, 2003

Introduction Bending stress evaluation in modern gear design is generally based on the more-than-... more Introduction Bending stress evaluation in modern gear design is generally based on the more-than-one-hundred-year-old Lewis equation. This equation, applied with the stress concentration factor Kf, defines the bending stress geometry factor J for traditionally designed standard ...

Direct Gear Design, 2013

This paper presents a unique approach and methodology to define the limits of selection for gear ... more This paper presents a unique approach and methodology to define the limits of selection for gear parameters. The area within those limits is called the "area of existence of involute gears" (Ref. 1). This paper presents the definition and construction of areas of existence of both external and internal gears. The isograms of the constant operating pressure angles, contact ratios and the maximum mesh efficiency (minimum sliding) isograms, as well as the interference isograms and other parameters are defined. An area of existence allows the location of gear pairs with certain characteristics. Its practical purpose is to define the gear pair parameters that satisfy specific performance requirements before detailed design and calculations. An area of existence of gears with asymmetric teeth is also considered.

analysis and design of spur and helical involute gears. Introduction Modern gear design is genera... more analysis and design of spur and helical involute gears. Introduction Modern gear design is generally based on standard tools. This makes gear design quite simple (almost like selecting fasteners), economical, and available for everyone, reducing tooling expenses and inventory. At the same time, it is well known that universal standard tools provide gears with less than optimum performance and— in some cases—do not allow for finding acceptable gear solutions. Application specifics, including low noise and vibration, high density of power transmission (lighter weight, smaller size) and others, require gears with nonstandard parameters. That’s why, for example, aviation gear transmissions use tool profiles with custom proportions, such as pressure angle, addendum, and whole depth. The following considerations make application of nonstandard gears suitable and cost-efficient: • CNC cutting machines and CMM gear inspection equipment make production of nonstandard gears as easy as product...

The contact ratio of spur gears is a critical parameter that affects gear drive performance. The ... more The contact ratio of spur gears is a critical parameter that affects gear drive performance. The influence of this parameter on the gear drive load capacity, efficiency, and noise and vibration is well known. There are studies (Refs. 1–3) dedicated to the analytical and experimental comparison of gears with low and high contact ratios. The dynamics and efficiency of high-contactratio asymmetric tooth gears were described in (Refs. 4–5). These publications explore contact ratio using a very similar evaluation approach. The gears are designed traditionally, based on a preselected basic (or generating) rack. This makes the contact ratio dependent on the number of teeth of mating gears, basic rack addendum, and X-shifts. A contact ratio is considered nominal, as it is designed without influence of deflections under the operating load. Comparable gear sets with different contact ratios are identical in numbers of teeth, tooth size, and modules. Such comparisons might have some theoretica...

Introduction When compared with the tradit ional gear design approach — based on pre-selected, ty... more Introduction When compared with the tradit ional gear design approach — based on pre-selected, typically standard generating rack parameters — the alternative Direct Gear Design (Ref.1) method provides certain advantages for custom, high-performance gear drives. Among them are increased load capacity; efficiency; length-of-service; reduced size and weight; noise/ vibrations; and cost. However, the manufacture of such nonstandard gears requires custom tooling and certain alterations of known gear fabrication processes. This paper presents specifics of application main methods of gear fabrication, i.e. — form and generating machining (cutting and grinding); gear forming injection molding technology; net forging; powder metal (PM) processing; die casting; and wire EDM gear prototyping. It also describes tooling profile definition, dependent upon the selected gear fabrication method. It presents the Genetic Molding Solution technique for compensation of differential warpage and shrinkag...

Journal of Mechanical Design, 2020

<jats:title>Abstract</jats:title> <jats:p>Veniamin I. Goldfarb, well-known scho... more <jats:title>Abstract</jats:title> <jats:p>Veniamin I. Goldfarb, well-known scholar and educator, passed away on November 12, 2019, at the age of 78. As Director of the Institute of Mechanics of the Izhevsk State Technical University, Professor Goldfarb was a towering figure in the field of power transmission and gearing, specializing in gear geometry, kinematics and contact mechanics.</jats:p>

The Proceedings of the JSME international conference on motion and power transmissions, 2017