Description

Product Overview

A helical gear shaft integrates a helical cylindrical gear and shaft body into a single component, with teeth arranged at a helix angle to the axis. Compared to straight gear shafts, helical gear shafts offer significantly larger contact ratio, smoother transmission, lower noise, and higher load capacity. They are extensively used in precision transmission applications with strict noise and vibration requirements, such as industrial robot reducers, EV reduction gearboxes, and high-precision machine tool spindle systems.

Yubao Transmission Technology uses CNC gear hobbing machines to produce helical gear shafts with helix angles from 0–45°, normal module range 0.5–3.0mm. After gear grinding, accuracy reaches DIN Grades 4–6 with tooth surface roughness Ra≤0.4μm. Precise control of helix angle, tooth alignment error, and axial pitch deviation ensures uniform contact pattern distribution across the tooth face, reducing transmission noise by 3–5dB compared to spur gears. Available in left-hand or right-hand helix configurations, with mating helical gears provided to ensure optimal contact performance.

Technical Parameters

Gear Parameters

Parameter	Symbol	Unit	Value/Range	Tolerance	Notes
Normal Module	mn	mm	0.5–3.0	—	Standard module series
Number of Teeth	z	—	Customized	—	Determined by transmission ratio
Normal Pressure Angle	αn	°	15°–30°	—	Typically 20° (standard)
Helix Angle	β	°	0–45°	±0.5°	Typically 8°–25°
Hand of Helix	—	—	Left/Right	—	Must match mating gear
Face Width	b	mm	Customized	±0.05	Must satisfy b×sinβ>mn
Accuracy Grade	—	DIN/ISO	7	—	Grinding achieves DIN 4–6
Axial Pitch Deviation	Fβ	μm	Per DIN standard	±	Key control parameter for helical gears
Tooth Surface Roughness	Ra	μm	0.4–1.6	≤	Ground teeth achievable 0.4

Shaft Parameters & Materials

Parameter	Symbol	Unit	Value/Range	Tolerance	Notes
Shaft Body Diameter	D	mm	21–350	h6–h9	Below gear root diameter
Total Length	L	mm	≤1500	±0.05	Overall length
Tooth Hardness	HRC	—	55–62	—	After carburizing
Core Hardness	HRC	—	30–45	—	Impact toughness assurance
Material Grade	—	—	20CrMnTi/16MnCr5	—	Premium carburizing steels
Heat Treatment	—	—	Carburizing + Tempering	—	Case depth 0.8–1.5mm
Balance Grade	—	G	G6.3–G2.5	≤	Required for high-speed shafts
Design Torque	T	N·m	Customized	≤	Design load
Design Speed	n	rpm	Customized	≤	Determined by helix angle and balance

Machining Capabilities

Process	Equipment	Range	Accuracy Achieved
Helical Hobbing	Ningjiang YK3610V/Chongqing SKS3112	Helix 0–45°, module 0.5–8mm	DIN Grades 6–7
Helical Grinding	Qinchuan YKZ7230 Worm Wheel Grinder	Helix 0–35°, module 0.5–3mm	DIN Grades 4–6
Heat Treatment	Carburizing Furnace	Case depth 0.8–1.5mm	Surface HRC 58–62
Gear Inspection	Gleason 300GMS Gear Tester	Profile/Alignment/Axial Pitch	100% verification
Dynamic Balance	Balancing Machine	Required for high-speed shafts	G6.3–G2.5 grade

Helix Angle Selection Guide

Application	Recommended Helix Angle	Characteristics
General Reducers	8°–15°	Improved smoothness, manageable axial force
Precision Servo Transmission	15°–25°	Low noise, high contact ratio
Quiet Applications	20°–30°	Lowest noise, bearings must handle higher axial load
High-Speed Transmission	10°–20°	Balance of smoothness and axial force

Important: Helical gearing produces axial force Fa = Ft×tanβ. Bearing selection must account for axial load capacity. Angular contact ball bearings or tapered roller bearings are recommended for combined loads.

Comparison: Straight vs. Helical Gear Shaft

Parameter	Straight Gear Shaft	Helical Gear Shaft
Transmission Smoothness	Moderate	Excellent (high contact ratio)
Noise Level	Medium	Low (3–5dB reduction)
Axial Force	None	Present (proportional to tanβ)
Load Capacity	Moderate	High
Machining Difficulty	Low	Medium
Bearing Requirements	Simple	Must handle axial loads
Applicable Speed	Medium-Low	Medium-High

Product Features

Ultra-Smooth Transmission: Helical tooth design achieves contact ratio >2, excellent engagement continuity, minimal vibration
Low Noise: 3–5dB noise reduction vs. equivalent accuracy spur gears, meeting quiet environment requirements
High Load Capacity: Long contact lines reduce unit area loading, strong anti-pitting capability
High-Speed Capable: Grinding accuracy DIN 4–6 with dynamic balance correction, suitable for high-speed applications
Direction-Customizable: Left-hand/right-hand helix available per transmission system layout requirements

Typical Applications

Application Sector	Specific Use	Typical Helix Angle	Accuracy
Industrial Robots	RV reducer/harmonic reducer gear shafts	15°–25°	DIN 5
Electric Vehicles	E-drive reduction gearbox shafts	20°–30°	DIN 5–6
Precision Machine Tools	Spindle transmission gear shafts	15°–20°	DIN 4–5
Construction Machinery	Forklift/excavator transmission	10°–20°	DIN 6–7
Wind Energy	Speed increaser gear shafts	15°–25°	DIN 5–6