Helical gears for transmissions, machines, and systems with uniform power transmission
As one pair of teeth disengages, other pairs of teeth are already bearing part of the load. This results in a more uniform power transmission. Operating noise, shock loads, and vibrations can be lower than with comparable straight-toothed gear pairs.
Typical applications include automotive transmissions, industrial gearboxes, machine tools, conveyor systems, pumps, compressors, wind turbines, and marine propulsion systems. We manufacture helical gears according to drawings and technical specifications, either as single units or in small batches.
Helical Gears for High Loads and High Speeds
Therefore, several points must be clarified before manufacturing:
The installation configuration is also critical. The axial force resulting from helical tooth engagement acts along the shaft. If this force is not taken into account in the bearing design, it can lead to increased bearing loads, unwanted shaft play, or damage to adjacent components.
Have helical gears manufactured according to drawings
Relevant information includes:
Profile Offset & Tooth Width
Head Circle and Foot Circle Diameters
Wheelbase
Materials & Heat Treatment
Gear Quality
Bore, hub, groove, and other mounting dimensions
Quantity
Information about the counterwheel
For a replacement part project, an existing sample, drawings of the assembly, and data on the mating gear can also be helpful. The specific direction and angle of the helix are particularly important. If these specifications do not match, the gears will not mesh correctly.
Advantages of Helical Gears
The teeth come into contact with one another gradually. As a result, the load build-up is less abrupt than with straight-tooth gears.
Lower Noise Levels
The smoother tooth engagement reduces harsh load transitions. This is particularly relevant in vehicle transmissions, machine tools, and continuously operating industrial equipment.
Higher Load Capacity
Multiple pairs of teeth can transmit load simultaneously. As a result, the stress is distributed over a larger contact area.
Smooth torque transmission
The load is transferred more continuously from one pair of teeth to the next. This reduces shock loads within the gear stage.
Suitable for high speeds
Helical gears are suitable for applications where smooth operation is required even at increasing circumferential speeds.
Lower Vibrations
The gradual tooth engagement can reduce vibration excitation in the gearbox. This benefits bearings, housings, and connected machine components.
High Power Transmission in Limited Installation Space
Due to the increased number of teeth bearing the load simultaneously, high loads can be transmitted in comparatively compact gear stages.
Helical Gears and How They Work
When two helical gears mesh, contact initially begins at a portion of the tooth flank. As the gears continue to rotate, the line of contact moves across the tooth width. Only then does the tooth disengage.
As a result, the meshing phases of multiple gear pairs overlap. While one gear pair is already disengaging, the next is already under load.
This process results in:
Selecting the angle of inclination is therefore always a compromise between running performance, load-carrying capacity, friction, and bearing stress.
Helical Gears and Resulting Axial Forces
This axial force must be supported by suitable bearings. Depending on the direction of rotation and the direction of the helix, it acts along the shaft in one direction or the other.
Therefore, the following points must be taken into account during design:
In the case of a simple helical gear, the appropriate axial bearing remains an essential component of the gear design.
Helical Gears for Industrial Gearboxes
Typical applications include:
In manual and automatic transmissions, many forward gears feature helical teeth. The gradual tooth engagement promotes smoother operation at high speeds.
Industrial Gearboxes
Drives for machines and production facilities use helical gears to transmit high torques during continuous operation.
Machine Tools
Spindle, feed, and auxiliary drives benefit from smooth operation and reduced vibration.
Conveyor Systems
Gearboxes for conveyor belts, hoists, and material transport systems often must operate smoothly over long periods and transmit high loads.
Pumps and Compressors
Low vibration and smooth tooth engagement are particularly important for continuously running drives.
Wind Turbines
Large gear stages transmit high power over long operating times. Helical gears are used in various gear stages in these applications.
Marine Propulsion Systems
Propulsion systems on ships require smooth power transmission and robust gear stages for continuous operation.
Helical Gears Compared to Straight-Tooth Gears
Straight-toothed gears have teeth that run parallel to the axis. Contact begins almost simultaneously across the tooth width. This simplifies manufacturing and prevents axial forces caused by the gearing. At high speeds, however, the tooth engagement may be more audible.
Helical gears engage in stages. This allows multiple pairs of teeth to transmit load simultaneously.
The most important differences are:
Helical gearing for specific operating requirements
Helical Gears from Dittler GmbH
Our range of services includes, among other things:
Our quality management system is certified according to DIN EN ISO 9001. To inspect the components, we use standardized testing procedures as well as a physically separate measuring room equipped with 3-coordinate measurement technology.
Many inquiries do not concern standard gears from a catalog. Instead, customers need a gear for an existing assembly, a replacement part, or a small batch produced according to their own drawings. Our manufacturing process is geared toward such individual parts and small production runs.
Helical gearing for smooth power transmission
This reduces harsh load cycles, operating noise, and vibrations. At the same time, axial forces are generated that must be absorbed by the bearings. Manufacturing costs and friction are also higher than with simple straight-toothed gears.
For industrial gearboxes, automotive transmissions, machine tools, conveyor systems, pumps, compressors, wind turbines, and marine propulsion systems, helical gearing offers a robust solution for continuous drive applications.
We manufacture helical gears to customer drawings, either as single units or in small batches. Complete gear tooth data and coordination with the mating gear, bearings, and installation configuration are essential.
Request Information on Helical Gears Now
Please send us your drawing and the available technical specifications using the contact form.
Information regarding the module, number of teeth, helix angle, helix direction, tooth width, material, heat treatment, and quantity is particularly helpful.
Questions About Helical Gears
What is helical gearing?
In helical gearing, the teeth are angled relative to the axis of rotation. As a result, contact between two teeth does not begin simultaneously across the entire width of the tooth. The meshing builds up gradually, allowing the force to be transmitted more evenly.
What are the advantages of helical gears?
Helical gears generally run more smoothly and quietly than spur gears. Multiple teeth can transmit load simultaneously, enabling a higher load-carrying capacity. They are therefore suitable for high speeds, high power, and continuously operating gearboxes.
Why do axial forces occur in helical gears?
Due to the helical profile of the gear teeth, a portion of the transmitted force is directed along the shaft axis. This axial force depends, among other things, on the helix angle, the torque, and the direction of rotation. It must be supported by bearings designed for this purpose.
What do "right-hand slant" and "left-hand slant" mean?
This term describes the direction in which the teeth run across the tooth width. A meshing pair of gears with parallel shafts typically requires opposite helical directions for external gears. Both gears must also have the same helix angle.
Are helical gears always quieter?
The stepped gear design provides good conditions for quieter operation. However, the actual noise level also depends on gear quality, bearings, lubrication, the housing, rotational speed, and installation. Therefore, helical gearing alone does not guarantee silent operation.
Why are helical gears more durable?
With a properly designed gear, several pairs of teeth are in mesh at the same time. This distributes the transmitted load across multiple contact areas. In addition, the load transfer is more uniform than with sudden tooth engagement.
What data is required to manufacture helical gears?
Key factors include the module, number of teeth, helix angle, direction of helix, angle of engagement, profile offset, and tooth width. Other factors include material, heat treatment, tolerances, mounting dimensions, and quantity. For a replacement part, the specifications of the mating gear should also be available.
What is the difference between helical and straight gears?
In straight-toothed gears, the teeth run parallel to the shaft axis. This type of gear does not generate axial forces and is generally easier to manufacture. In helical gears, the teeth mesh in a stepped pattern. As a result, they often run more smoothly at high speeds, but they generate axial forces and higher friction.
What effect does the rake angle have?
A larger helix angle can increase the number of teeth in contact at any given time and result in smoother operation. At the same time, the axial forces and the sliding components on the tooth flanks generally increase. The angle must therefore be selected to suit the load, rotational speed, and bearing configuration.
Can helical gears be manufactured as single pieces?
Yes. Helical gears are often needed as one-off parts for special-purpose machines, repairs, and existing gearboxes. It is crucial that all gear tooth data is clearly available and that the component can be machined with the appropriate tools.
Why is the efficiency slightly lower than that of a spur gear?
The helical tooth profile causes additional sliding movements between the tooth flanks. These movements increase friction. The extent of this increase depends on the helix angle, lubrication, load, and gear geometry, and must be weighed against the benefits in terms of running performance.
In which applications are helical gears preferred?
They are primarily used in automotive transmissions, industrial gearboxes, machine tools, conveyor systems, pumps, compressors, wind turbines, and marine propulsion systems. They are particularly well-suited when high speeds and power outputs need to be combined with the smoothest possible operation.