Our oval gears
We manufacture oval gears for machines and systems in which the output speed is intended to vary in a controlled manner within a single revolution. The motor can run at a constant speed during this process. The shape of the oval gear pair ensures that a gripper, tool, conveyor, or transport element accelerates during a work cycle and then decelerates again.
Oval gears are used, among other things, in packaging machines, textile machines, printing presses, conveyor systems, and in automation and assembly technology. We manufacture oval gears according to drawings, technical specifications, or an existing sample, either as single units or in small batches.
Oval Gears at Varying Conveyor Speeds
A gripper must pick up a product slowly so that it does not slip or get damaged. It must then travel to the next station as quickly as possible. Before handoff, the speed is reduced again.
Similar requirements arise when transporting paper, films, textiles, and workpieces. A standard round gear cannot produce such speed changes based solely on its geometry, since its gear ratio remains constant during rotation.
Therefore, several points must be clarified before placing a manufacturing order:
Have oval gears manufactured according to drawings
Relevant technical specifications include:
Contour of the oval wheel
Type and Design of the Gear Tooth Profile
Module and Number of Teeth
Center distance of the gear pair
Oval gears typically operate as a matched pair. If only one of the two gears is to be replaced, it must match the existing contour and tooth profile. If reliable data is unavailable or if the mating gear already shows significant wear, it may make more sense to manufacture a new pair of gears.
Advantages of Oval Wheels with Variable Gear Ratios
The motor can operate at a constant speed. Nevertheless, the output accelerates and decelerates within each revolution.
Mechanically Defined Motion Sequence
The desired motion profile is encoded in the shape of the oval gears. Continuous electronic control is not required for this sequence.
High Repeatability
When properly installed, the individual motion phases repeat with every revolution. The output always reaches the specified speed ranges at the same positions.
Compact machine design
In suitable applications, a pair of oval wheels can replace additional gear stages, cam discs, or control components.
Robust construction
The motion profile is generated by direct tooth engagement. This is particularly advantageous for machines that perform the same work cycle over long periods of time.
Reduced Load on the Drive
The motor does not need to be electronically accelerated and decelerated for each work step. The change in speed occurs within the gear pair.
Use in Existing Machines
In older systems, the existing mechanical operating principle can be retained without having to completely convert the machine to a controlled drive.
Oval Gears and How They Work
In a circular gear, the effective distance between the axis of rotation and the point of tooth engagement remains constant throughout a full revolution. Therefore, the rotational motion is transmitted at a constant gear ratio.
With an oval gear, this effective distance changes continuously. In one part of the revolution, a larger effective radius is engaged. In another part, the effective radius is smaller.
This changes the current gear ratio between the drive and the driven gear. Although the driving gear rotates at a constant speed, the driven gear alternates between running faster and slower.
A typical sequence of movements might look like this:
- A Gradual Approach to a Product
- Controlled pickup by a gripper
- Faster transportation to the next station
- Slowing Down Before the Handoff
- Return to the starting position
The actual motion results from the interaction of the two oval wheels. The contour of one wheel cannot be defined independently of the other. Both geometries must mesh with each other throughout the entire rotation and maintain the specified center distance.
The angular position of the wheels relative to one another also affects operation. If they are rotated relative to one another during installation, the timing of acceleration and deceleration shifts. Therefore, reference points and installation positions should be clearly documented.
Oval Wheels for Packaging Machines and Conveyor Systems
Oval wheels are suitable for applications in which movement must occur at different speeds within a repeating cycle.
Typical applications include:
The oval-wheel geometry must be considered separately for each specific application. A motion profile designed for a packaging gripper cannot be applied unchanged to a paper conveyor or a textile feeding device.
Oval gears for specified motion profiles
Oval wheels are particularly well-suited for machines whose motion sequence is fixed over the long term. While this characteristic is an advantage, it also imposes limitations on the application.
The manufacturing process is more complex than for round gears. The tooth profile follows a non-circular contour, and both gears must work together in perfect coordination throughout the entire revolution.
Higher requirements also apply to design and assembly:
Oval wheels are therefore particularly useful when the same work sequence is repeated continuously and no ongoing software adjustments are required.
For machines that frequently switch between different motion programs, an electronically controlled solution may be more suitable. The key factor is not which technology is fundamentally more powerful, but which solution is best suited to the actual machine process.
Oval gears from the manufacturer Dittler GmbH
Oval gears, elliptical gears, and other non-circular gears are among the specialized gear types we specialize in manufacturing. Our customers often do not need a standard part from a catalog, but rather a component for a specific machine, an existing drive system, or a precisely defined motion sequence.
Our manufacturing capabilities include, among other things:
Our quality management system is certified according to DIN EN ISO 9001. To inspect components, we use, among other things, a physically separate measuring room equipped with 3-coordinate measuring technology.
For recurring custom-made parts, we ensure that the manufactured gear sets are traceably assigned. This simplifies future spare parts projects and helps us to recreate the original installation configuration and gear pairing.
Oval gears for periodic speed changes
This allows the driven component to start slowly, accelerate, and decelerate again before power is transferred. This sequence repeats mechanically with each revolution.
Oval gears are suitable for applications such as packaging machines, textile machines, printing presses, conveyor systems, assembly equipment, and special-purpose machines. They are particularly useful for fixed work cycles that remain unchanged over long periods.
The design, gear pair, center distance, and installation position must be considered together. We manufacture oval gears according to drawings, technical specifications, and—depending on the initial situation—also based on an existing sample, either as a single piece or in small batches.
Request and Have Oval Gears Manufactured
Send us your drawing, technical data, or information about the existing assembly via the contact form. For an initial assessment, details regarding the gear teeth, center distance, material, quantity, and desired motion profile are particularly helpful.
For replacement parts, please also include, if possible, the mating gear, the installation position, and any existing documentation for the machine. This makes it easier to determine whether a single oval gear can be replaced or whether a new, matched set is required.
Frequently Asked Questions About Oval Gears and Oval Wheels
What is an oval gear?
An oval gear is a non-circular gear whose effective radius changes as it rotates. As a result, the instantaneous gear ratio is not constant. Despite a constant drive speed, the driven gear rotates faster in certain sections and slower in others.
Are oval gears a type of non-circular gear?
Yes. Oval gears belong to the broader category of non-circular gears. This term encompasses gears with a non-circular effective contour. In addition to oval designs, this category may also include elliptical gears and other specially calculated shapes. Therefore, not every non-circular gear is automatically an oval gear.
How do oval gears differ from round gears?
With a circular gear, the gear ratio remains constant throughout one revolution. With an oval gear, the effective radius changes, and with it, the instantaneous gear ratio. A circular gear thus provides uniform power transmission, while an oval gear allows for deliberately varying speeds.
Why are oval gears designed as pairs?
The desired motion results from the interaction of the two gears. Their contours must mesh with one another throughout the entire revolution and maintain the specified center distance. Therefore, the shape of an oval gear cannot be determined independently of its mating gear. Both gears form an integrated transmission system.
What information is needed to manufacture oval wheels?
Ideally, a technical drawing should be available that includes the outline, gear teeth data, module, number of teeth, center distance, bore, hub, and material. In addition, the desired speed profile should be known. For a replacement part project, the existing mating gear, the installation position, and documentation regarding the machine are also helpful.
Can oval wheels replace an electronic control system?
For a fixed, regularly recurring motion sequence, oval wheels can generate a variable output motion without continuous electronic speed control. However, they do not replace a servo drive in every application. If the motion profile needs to be changed frequently during operation, a programmable solution is usually more flexible.
What is the significance of the angular position of the oval wheels?
The angular position determines at which point in the operating cycle the output shaft accelerates or decelerates. If the gears are installed at an angle to one another, the entire motion sequence shifts. For this reason, mounting positions should be clearly defined using reference points or markings.
Can individual damaged oval wheels be replaced?
In principle, replacing a single gear is possible if reliable geometric data is available and the existing mating gear is still in suitable condition. If drawings are missing or the mating gear shows signs of wear, it should be determined whether it makes more sense to manufacture a new, matched pair.
What are the disadvantages of oval gears?
The manufacturing process is more complex than that for round gears. In addition, both gears must be designed together and positioned correctly relative to each other during assembly. The motion profile is determined by the geometry and cannot be adjusted later without modifying the gears.
For which machines are oval wheels particularly suitable?
Oval wheels are suitable for machines with repetitive work cycles and varying speeds. Typical examples include packaging machines, textile machines, printing presses, conveyor systems, and assembly equipment. It is crucial that the required motion profile is fixed and repeats regularly.
Are oval gears available as individual parts?
Yes. Oval gears are often required for special-purpose machines, spare-part projects, or small assemblies. Therefore, they can be manufactured as single units or in small batches. If there is a long-term need for spare parts, it may make sense to have several matched pairs manufactured.
How is the motion profile of an oval wheel determined?
The starting point is the desired motion of the machine. It must be determined at which position the output shaft should run slowly, accelerate, or decelerate. The required change in the gear ratio is derived from this profile. The profiles of both gears are then adjusted accordingly.