Worm Gears & Worms

Geyontech precision worm gears and worms. Z1~Z6 profiles, bronze worm gears, steel worms.

Specifications#

Worm Gear Sets: Specifications, Selection and Grinding for High Ratios and Self-Locking Drives#

Worm gear pairs handle crossed-axis transmission, with the two shafts usually arranged at 90°, used in positions requiring large reduction ratios and compact structures. Geyon Transmission worm modules cover M1~M12, with 1~6 threads, lead angles of 3°~30°, and material options of 20CrMnTi or 42CrMo, with tooth surface hardness of 58~62 HRC after carburizing and quenching; worm grinding accuracy reaches GB class 6~7, while batch milling and hobbing achieve GB class 7~8. Worm wheels are matched with tin bronze, aluminum bronze, or ductile iron according to working conditions, with hobbing range of M1~M12 and reduction ratios covering 7.5:1 to 80:1. Pitch, profile, and helix are measured with a gear measuring center, with reports shipped alongside the goods. Tooth profiles are made in ZA, ZN, ZI, and ZK types, with specific dimensions according to drawings.

1. Where Worm Gear Pairs Are Used#

One worm drives one worm wheel, and the reduction ratio can reach 80:1 — a figure that gear pairs of the same volume cannot provide. The 90° shaft angle layout also saves space — the worm enters from the side, the worm wheel exits from the other side, and the equipment footprint can be narrowed.

The cost is efficiency. A single-thread worm has a small lead angle, with efficiency of only 60~70%, and part of the input power becomes heat, so the housing needs to consider heat dissipation or added cooling. But it has a property others cannot provide: self-locking. When the lead angle is small enough, the worm wheel cannot push the worm in reverse, and mechanisms such as lifting, elevating, and clamping that “must not slide down on their own after power loss” often rely on this.

The more threads, the higher the efficiency and the weaker the self-locking property. Multi-thread worms can reach 85~92% efficiency while also losing self-locking. So when selecting, first ask yourself: do you want efficiency or self-locking? If you want both, you usually have to change the scheme.

2. Specification Parameters#

Common range for the worm side:

The worm wheel side is divided into three grades according to matching material:

Reference correspondence between efficiency and self-locking:

The efficiencies in the table are approximate values; actual values are related to tooth surface roughness, lubrication method, and assembly alignment. If self-locking is to be used as a design premise, it is safer to calculate it based on the actual lead angle and friction coefficient.

There are four common tooth profiles for worms, and which one to choose depends on machining and load capacity: ZA Archimedes worm has a straight profile on the axial section, making machining and measurement simple; ZN normal straight profile is suitable for grinding; ZI involute worm is straight on the base cylinder tangent plane, with good accuracy after grinding; ZK conical enveloping worm is formed by grinding wheel enveloping, suitable for batch grinding. Once the tooth profile is determined, the tool, grinding wheel, and measurement method can be determined accordingly.

3. Machining Capability and Accuracy#

Supporting turning and grinding capabilities: CNC turning accuracy 0.005 mm, cylindrical and face grinding 0.001 mm, hobbing single-tooth cycle time 5 seconds. During the design stage, KISSsoft is used for strength and meshing verification, and CAD, Solidworks, Caxa, and Mastercam are all in the process, producing drawings and machining files.

4. How the Process Route Works#

Worm teeth are carburized and quenched first. 20CrMnTi is carburized and quenched to 58~62 HRC, with a wear-resistant surface layer and retained toughness in the core, so it is not prone to tooth breakage under heavy and rough working conditions. For occasions with slightly lower requirements, the 40Cr quenching and tempering or induction hardening route is used, with tooth surface 48~55 HRC.

Grinding is divided into rough and fine passes. After quenching, the tooth surface deforms, so rough grinding restores it first, then fine grinding achieves the accuracy required by the drawing. After grinding, the worm can reach GB class 6~7, one grade higher than the milled state, and both noise and heat generation decrease accordingly.

Worm wheel tooth thickness and center distance are controlled. Tin bronze worm wheels are hobbed to M1~M12, and tooth thickness tolerance and center distance deviation must be held — the worm and worm wheel are in line contact, so if the center distance deviates slightly, the contact area shifts and wear becomes concentrated.

Pairing inspection. Paired parts are machined in pairs and shipped in pairs, with contact patch position and area checked pair by pair and rechecked with a meshing tester. The inspection chain is a gear measuring center (capable of measuring cylindrical gears, bevel gears, worm gear pairs, and splines) + CMM + hardness tester + roughness tester, with key dimensions and hardness measured item by item.

Reports included at shipment. Gear inspection reports are shipped with the goods, including pitch deviation, profile deviation, helix deviation, and tooth surface hardness. With data in hand, customers can distinguish whether a problem during installation is due to the gear or due to assembly.

5. These Devices Are Using Them#

• Industrial reducers: Worm gear reducers are the main application, with center distance and reduction ratio determined according to the housing drawing.
• Indexing tables / rotary tables: Worm gear pairs are used for indexing, and pitch deviation directly affects the indexing angle, so the accuracy class must be specified according to indexing requirements.
• Conveying and lifting equipment: Single-thread worms self-lock, so the conveying section will not slide backward when stopped.
• Crossed-axis transmission with limited space: 90° transmission, with the worm entering from the side, so the housing layout can save space.
• Non-standard transmission units: Machined to drawing, with a machinability review first, then tooth profile, tooling, and inspection scheme determined.

6. Send Drawings Over, Get a Review Before Quotation#

Reducer manufacturers, indexing table manufacturers, equipment OEMs, and traders all connect directly. Send PDF, DWG, or Solidworks drawings, or provide the four parameters of module, threads, teeth, and accuracy class, and engineering will first conduct a drawing review and reply with the process route, worm wheel material recommendations, and inspection scheme. The worm gear product page has classification descriptions, and matching cylindrical gears can be supplied together.

Inquiry method: send drawings → drawing review → quotation → prototyping or batch production. Email sales@geyontech.com , with the subject line “Worm gear inquiry”.

• Worm gear product page
• Machining capability overview
• Inspection and quality system
• Send drawings for quotation

For more product information, see the Geyon Transmission official website.

Manufacturing processes#

• Worm grinding
• Worm wheel hobbing (dedicated hob)
• Matched-set running-in and inspection of the worm gear pair

Features#

• High reduction ratio (5~100)
• Self-locking (lead angle < 3.5°)
• Low-noise operation

Applications#

• Industrial gear reducers
• Precision positioning in automation
• Elevator and lifting equipment