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Helical Bevel Gear
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Helical Bevel Gear
Helical Bevel Gear
Spiral Bevel Gear | Helical Bevel Gear
Spiral Bevel Gear
The Working Principle of Spiral Bevel Gears
A spiral bevel gear transmits rotational power between two intersecting shafts — most commonly at 90° — by means of curved, helical tooth profiles cut along a conical surface. When the driving gear rotates, its teeth engage the mating gear progressively rather than all at once: contact begins at one end of each tooth and sweeps smoothly across to the other end. This gradual engagement is fundamentally different from straight bevel gears, where full-face contact occurs instantaneously.
Because of the overlapping tooth end faces, at least two pairs of teeth remain in mesh simultaneously at any point in the rotation cycle. This overlap coefficient — typically greater than 1.0 for well-designed spiral bevel gears — is why they can transmit more load with less vibration and noise than a straight or zero-degree bevel gear of the same module. The tooth surface contact area can be precisely tuned during gear cutting by adjusting the cutter radius, allowing engineers to optimize load distribution for specific operating conditions.
Hypoid spiral bevel gears extend this concept further: the pinion axis is offset from the ring gear axis, enabling a lower profile installation and allowing larger pinion diameters for greater torque capacity — which is why virtually every automotive rear-axle differential uses a hypoid gear set.
Other Products We Manufacture
-- Related Products--
Spiral Bevel Gears
The flagship product line. Modules M0.5–M8 in standard production, up to M12 on request. OD up to 600mm. Precision DIN6–DIN9. Material grades from brass and aluminum for light-duty automation to 20CrMo and 18CrNiMo7-6 for heavy industrial drives.
Spiral angle: 35°–45° standardHelical Bevel Gear Units
Tangential bevel tooth geometry with greater coincidence degree than spur bevel gears. Particularly suited to high-speed industrial machinery, agricultural PTO drives, and automated machine tools. Manufactured to ISO H7/H8 bore tolerances.
Helix angle: 8°–50° on requestHypoid Bevel Gears
Offset axis design for vehicle differentials, low-profile industrial drives, and applications requiring a larger pinion diameter for increased torque capacity. Gear ratio up to 25:1 per stage. Always supplied as matched ring-and-pinion pairs.
Ratio range: up to 25:1Gear Shafts & Spline Shafts
Combined gear-and-shaft components including pinion shafts and gear drive shafts in 18CrNiMo7-6 and 20CrMo. Spline profiles to ISO H7/H8/H9. Used extensively in agricultural power transmission and construction machinery drive trains.
Spline ISO H7 · H8 · H9Gear Couplings & Assemblies
42CrMo gear couplings (Q&T HB 280–320) and complete planetary gearbox assemblies (nitrided, DIN7 grade) for robotics, construction machinery, and renewable energy applications. Full assembly and test service available.
Material: 42CrMo · Q&T HB280–320Straight Bevel Gears & Custom Types
Straight bevel, miter, zero-degree bevel, and custom non-standard geometries available on drawing. Suitable for low-speed, lower-noise-requirement applications. Brass straight bevel gears are available for printing machinery and precision instrument drives.
Non-standard acceptedWhat Are Spiral Bevel Gears Made Of?
Material selection for spiral bevel gears is driven primarily by the load magnitude, operating speed, and environmental conditions. We stock and process a broad alloy range to match your specification exactly.
Case-Hardening Alloy Steel
20CrMo and 18CrNiMo7-6 are the primary choices for high-load spiral bevel gears. Carburized and quenched to HRC 58–62, with a carburized case depth of 0.8–1.2 mm, they deliver exceptional surface hardness while maintaining a tough core at HRC 35–42.
Medium Carbon & Alloy Steel
C45 and 42CrMo are used for moderate-load applications. Induction-hardened teeth (HRC 55–60) with quenched-and-tempered cores (HB 280–320) offer a practical balance of wear resistance and machinability, well suited for industrial gearboxes and construction machinery.
Stainless Steel & Non-Ferrous
Stainless steel grades are available for food processing and pharmaceutical environments requiring corrosion resistance. For lighter-load applications — such as semiconductor automation or medical equipment — we also work with brass, aluminum alloys, copper, and engineering plastics (POM).
Surface Treatments
We offer zinc-plating, nickel plating, black oxide, Dacromet, Geomet, phosphatizing, powder coating, anodizing, and electrophoresis. Salt spray test verification available up to 240 hours — critical for outdoor and marine drive applications.
Spiral vs. Straight Bevel Gears — Which Should You Choose?
Engineers frequently ask about the difference between straight bevel gears and spiral bevel gears. The answer depends on your speed, load, and noise requirements.
| Attribute | Spiral Bevel Gear ✓ | Straight Bevel Gear |
|---|---|---|
| Load Capacity | Higher (2+ teeth in mesh) | Lower (1 tooth at a time) |
| Operating Noise | Significantly lower | Higher at speed |
| Transmission Efficiency | 96–98% | ~96% (lower at high speed) |
| Suitable Speed Range | Low to high (recommended) | Low to moderate speed only |
| Minimum Tooth Count | 5–6 teeth possible | 12+ teeth typically |
| Bidirectional Operation | Yes (both directions) | Yes |
| Vibration Level | Minimal | Moderate to high |
| Manufacturing Complexity | Higher (specialized CNC) | Simpler |
Trust us
From automotive differentials to heavy mining drives, our spiral bevel gears and helical bevel gear units deliver 96–98% transmission efficiency, DIN6–DIN9 precision.
Dedicated Manufacturing Facility
Over 250 CNC machining centers, gear hobbers, grinding machines, and precision test instruments operate around the clock. We don’t broker production — everything happens under one roof.
Divix Studio
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100% Inspection Before Shipment
Every batch goes through chemical composition analysis, mechanical performance testing, 100% ultrasonic inspection (EN10228-3, SA388), heat treatment records, and dimensional CMM verification.
How to Choose the Right Spiral Bevel Gear
Follow these four steps to narrow down your specification. When you're ready, send us a drawing or inquiry and our engineers will confirm the selection.
Define Torque & Speed
Specify input torque (Nm), input RPM, and required output shaft speed or ratio. This sets the module and material grade.
Set Shaft Angle & Offset
Standard spiral bevel gears work at 90°. If axes don't intersect, specify the offset distance — that points to a hypoid gear set.
Choose Material & Surface
High load → 20CrMo or 18CrNiMo7-6, carburized. Corrosive environment → stainless or Dacromet/Geomet coating.
Send Your Drawing
Email PDF, DWG, or STEP files to [email protected]. We quote within 24 hours on standard requests.
FAQ
Q1. How do spiral bevel gears produce less noise than straight bevel gears at high speeds?
The curved tooth geometry ensures that tooth engagement is gradual and progressive — contact begins at one end of the tooth face and sweeps to the other, so load transfer is distributed over time rather than applied as an impulse. At any instant, at least two tooth pairs share the load, smoothing out the torque ripple that generates noise. Straight bevel gears, by contrast, engage a full tooth face all at once, creating a periodic impact that becomes acoustic vibration at high RPM. Additionally, the local contact area on a spiral bevel gear can be tuned during manufacture to minimize the transmission error that is the primary source of gear whine.
Q2. Can spiral bevel gears rotate in both directions, or are they unidirectional?
Yes, standard spiral bevel gears are fully bidirectional — they can rotate in both clockwise and counterclockwise directions. However, the hand of the spiral (left-hand or right-hand) determines the direction of axial thrust load on the shaft bearings, and this must be accounted for in bearing selection and housing design. A spiral bevel gear set manufactured as a left-hand/right-hand pair should always be replaced as a unit, since the gears are lapped together and optimized as a matched set.
Q3. Which is better for a mining conveyor drive — a worm gear or a spiral bevel gear gearbox?
For a mining conveyor drive with high continuous load and duty cycle, a helical bevel gearbox is generally the better choice. The efficiency advantage is decisive: a spiral bevel stage runs at 96–98% efficiency per stage, while a worm gear at a similar reduction ratio typically delivers 60–85% efficiency. Over the lifetime of a continuously running conveyor, the energy savings are substantial. Worm gears offer self-locking capability and extreme ratios in a very compact envelope, which makes them useful for specific positioning or low-duty-cycle applications — but high-power continuous drives are where bevel gear technology clearly wins on running cost.
Q4. What is the difference between a miter gear and a spiral bevel gear, and when should I use each?
A miter gear is simply a bevel gear used in a 1:1 (equal) ratio pair with 90° shaft angle — it changes shaft direction without changing speed or torque. A spiral bevel gear, by contrast, can be used at any ratio from 1:1 up to about 10:1 per stage, and its curved teeth give it a significant advantage in noise and load capacity at higher speeds. Use miter gears when you need a simple direction change at equal speed; use spiral bevel gears when you need a ratio change, or when operating conditions demand lower noise, higher load capacity, or better efficiency than straight-cut miter gears provide.