설명
Parallel-shaft spur gear
Spur gears are a direct choice for many parallel-shaft mechanisms. Working performance still depends on center distance, bore/shaft accuracy, mating gear, material, face width and backlash.
A press-fit bore can expand the hub and subtly change tooth runout or root stress. When the hub is relatively thin, the shaft fit should be reviewed together with the gear material and molding history. If a keyed or D-shaped bore is used, show the torque path rather than specifying bore size alone.
How to read the product photograph
The main image is a photograph of a physical sample or representative component, not a dimensional definition. Resin colour, tooth count, bore or hub features, rack length, inserts and other details can change with the released drawing. Use the photograph to understand the product family; use the controlled drawing, mating interface and agreed inspection plan to manufacture and approve the part.
Geometry and interface inputs for Plastic Spur Gears
- Tooth count, module/DP and pressure angle
- Face width and outside diameter limits
- Bore, hub, keyway or press-fit details
- Mating gear and center distance
- Speed, load, duty and noise target
Geometry reference: Straight-tooth parallel-axis gear
Choosing the production route
Spur gears can be injection molded for repeat volumes or machined for lower-volume, larger or material-specific projects. Secondary bore or datum machining may be considered when the assembly requires it.
Packaged process reference: Molded and machined plastic spur gears are separate routes
Material direction: POM, nylon and other engineering polymers by requirement
Application-specific design review
Tight center distance, excessive press fit, shaft runout or thermal/moisture growth can reduce working backlash and increase noise or wear.
Typical use: Printers, appliances, packaging mechanisms, automation and general compact drives. The final material and tolerance plan should be checked against the load path, mating components and environment in that assembly.
First sample and inspection focus
Use drawing-defined gear measurements together with bore/runout checks. An assembled roll or functional mesh check may reveal issues not visible from a single diameter measurement.
Quotation decision: Module or DP, tooth count, pressure angle, bore, hub, face width, mating center distance and backlash define the core configuration.
What to send for a Plastic Spur Gears quotation
Send the latest drawing or CAD model together with production quantity and the application conditions that affect fit, wear or dimensional stability. If the part replaces an existing component, identify the features that must remain interchangeable and any known field issue the new part is intended to solve.
- Controlled drawing revision and 3D model when available
- Mating-part or transmission geometry
- Material requirement or service environment
- Sample quantity, production batch and expected annual demand
- Critical dimensions and functional acceptance method
Engineering specification to freeze before manufacture
A production drawing should convert the application into measurable inputs. The table below is the minimum review set for this product family; add any assembly-specific datum, finish or acceptance requirement that changes function.
| Definition | What the supplier needs |
|---|---|
| Module or DP | Show the value, tolerance or functional requirement on the latest drawing. |
| Pressure angle | Show the value, tolerance or functional requirement on the latest drawing. |
| Tooth count | Show the value, tolerance or functional requirement on the latest drawing. |
| Face width | Show the value, tolerance or functional requirement on the latest drawing. |
| Bore / key / D-flat | Show the value, tolerance or functional requirement on the latest drawing. |
| Hub geometry | Show the value, tolerance or functional requirement on the latest drawing. |
| Mating center distance | Show the value, tolerance or functional requirement on the latest drawing. |
| Torque, speed and working backlash | Show the value, tolerance or functional requirement on the latest drawing. |
Failure modes to prevent during design review
Common risks for this geometry include insufficient working backlash; bore-induced runout; hub/root stress from aggressive press fit. These are best addressed before the first sample by reviewing the complete mating interface, not by tightening every drawing tolerance.
Use tolerances selectively. Dimensions that establish the tooth mesh, chain engagement, shaft fit or assembly datum deserve explicit measurement methods; non-critical molded surfaces can often use a more practical general tolerance.
First-article and production acceptance
Agree the inspection condition, datums and measuring method before sampling. The first-article report should cover the drawing CTQs and then be paired with a functional check in the real assembly or a representative fixture. For gears and sprockets, that can include mesh or chain engagement, runout and bore relationship; for custom molded parts it can include fit, fastening and loaded features.
Production control should follow the same CTQs rather than replacing them with a long list of easy-to-measure cosmetic dimensions. If a bore, tooth, insert or mounting surface is secondary-machined, make clear which operation establishes the final datum.
Engineering decision brief for Plastic Spur Gears
Define the geometry
Straight-tooth parallel-axis gear The quotation should use the drawing revision and mating interface as the controlling definition rather than an image alone.
Choose material by duty
POM, nylon and other engineering polymers by requirement Material selection should be checked against load, speed, temperature, moisture or chemicals, lubrication and the required dimensional condition.
Freeze the production route
Molded and machined plastic spur gears are separate routes The route should be fixed only after quantity, tolerances, surface requirements and change risk are understood.
Agree acceptance
Module or DP, tooth count, pressure angle, bore, hub, face width, mating center distance and backlash define the core configuration. First-article checks should therefore focus on the dimensions and functional interfaces that control the assembly.
Typical application context: Packaging, conveyors, office equipment, instruments, small machinery and custom electromechanical assemblies.
Plastic Spur Gears FAQ
What should I send for quotation?
Send the latest 2D drawing and, where available, a 3D model. Add mating-part information, order quantity, service conditions and the features that control fit or motion. A sample is useful for replacement parts with uncertain legacy geometry.
How should the material be specified?
For POM or nylon projects, material family alone is not enough. Confirm the actual grade when it is mandatory, and state moisture, temperature, lubricant and mating material so dimensional and wear behavior can be reviewed.
How is the first sample approved?
Define the CTQs, inspection state and functional test before the sample is produced. Approval should confirm both measurable geometry and the behavior of the part in its intended interface.
