How To Ensure The Safety of Planetary Gear Transmission? A Detailed Explanation of Planetary Gear Transmission Strength Design
Publish Time: 2025-08-04 Origin: Site
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Whether the design of planetary gear transmission is safe mainly depends on two most important safety factors: tooth surface contact fatigue strength and tooth root bending fatigue strength. As the most important design points of planetary gear transmission, mastering their related knowledge is crucial for engineering practitioners.
2.1 Brief Introduction to Planetary Gear Transmission
2.2 Material Selection for Planetary Gear Transmission<div class="auto-hide-last-sibling-br mdbox-table-root table-container-GhL7Lo" data-scroll-inline-at-end="false" data-scroll-inline-at-start="true" data-scroll-inline-end-overflow="true" data-scroll-inline-overflow="true" data-scroll-inline-start-overflow="false" segoe="" ui",="" "sf="" pro="" sc",="" display",="" icons",="" "pingfang="" "hiragino="" sans="" gb",="" "microsoft="" yahei",="" "helvetica="" neue",="" helvetica,="" arial,="" sans-serif;="" font-size:="" 16px;"="" xmlns="http://www.w3.org/1999/xhtml" style="outline: none; -webkit-font-smoothing: antialiased; box-sizing: border-box; -webkit-tap-highlight-color: rgba(0, 0, 0, 0); --tw-translate-y: 0; --tw-rotate: 0; --tw-skew-x: 0; --tw-skew-y: 0; --tw-scale-x: 1; --tw-scale-y: 1; margin-bottom: -4px; max-width: 1256.72px; width: 1256.72px; position: relative; --table-inline-padding: 48px; --table-width: calc(100cqi - 48px*2); margin-left: -231.859px; overflow-anchor: auto;">
| Gear Material Selection | ||||||
|---|---|---|---|---|---|---|
| 1 | Sun Gear A | |||||
| Material | 20CrMnMo | |||||
| Surface Treatment | Carburizing and Quenching | |||||
| Hardness | 58 HRC | Tooth surface hardness: HRC 56-60; Core hardness: HRC 30-42 | ||||
| Contact Fatigue Limit | σHlim | 1500 N/mm² | The contact fatigue limit and bending fatigue limit of test gears are selected according to the relevant block diagrams in Chapter 1 | |||
| Allowable Contact Stress | σHP | 1350 N/mm² | ≈0.90σHlim | |||
| Bending Fatigue Limit | σFlim = 500 N/mm² | For NGV-type transmission, regardless of bidirectional operation or not, the tooth root of the planetary gear is subject to alternating loads, so the bending strength should be considered under symmetric cycle. For unidirectional transmission, the selected σFlim value should be multiplied by 0.7; for bidirectional transmission, it should be multiplied by 0.7-0.9 (selected according to MQ-level quality requirements in Figures 14-1-24 and 14-1-53) | ||||
| 2 | Planetary Gear C | |||||
| Material | 20CrMnMo | |||||
| Surface Treatment | Carburizing and Quenching | |||||
| Hardness |