ABB 3HAC039109-003 Reduction Gear for IRB 2600 / IRB 4600 Axes 2-3

Reduction Gear for ABB IRB 2600 and IRB 4600 Robots

Specifications

Industrial Applications

• IRB 2600 and IRB 4600 cells in material handling, welding, machine tending and general assembly, where the arm joints carry the working load.
• Replacement of a joint gearbox showing increased backlash, noise or loss of repeatability.
• Recovery after a collision or overload that has damaged the gear teeth or bearings.
• Scheduled major overhaul where joint gears, seals and oil are renewed together.
• Refurbishment of a used robot before it goes back into a production cell.

Design Purpose

A servo motor delivers speed, not torque. A robot arm needs the opposite, so every major joint carries a reduction gear: it takes the motor's high rotational speed down to a working joint speed and multiplies the torque by the same proportion. That single conversion is what lets a relatively small motor move a loaded arm and hold it in position, and it is also the mechanical element that sets the joint's stiffness and repeatability.

Because the gear is what defines the joint's accuracy, it is a matched part rather than a commodity one. The gear that fits axis 2 is not the gear that fits axis 4, and the same axis can use different gears across robot variants — so the article number is tied to the axis position, the robot model and, in practice, the serial number. This article also sits at a point where ABB updated its numbering: 3HAC039109-003 appears among the replaced product IDs for 3HAC039109-002, which is why the cross-reference is worth checking rather than assuming. In service, a joint gear is renewed when backlash, noise or positioning error says the gear train is worn, and the job is planned around oil, seals and a position check afterwards.

Common Failure Modes

• Increased backlash or lost repeatability — the gear train is worn and the joint no longer holds position accurately.
• Noise or vibration from the joint under load, often the first sign of gear or bearing wear.
• Oil leakage at the joint seals, followed by lubrication loss and accelerated wear.
• Gear tooth or bearing damage after a collision, overload or repeated shock loading.
• Positioning drift or axis error that reappears after the counter procedure has been repeated.
• Wrong gear fitted — matched by appearance or by axis number instead of by article number and serial number.

Specific alarm codes are not officially documented for this model. Please contact us with the fault code displayed on your controller for accurate diagnosis.

Why Choose Us

• Specialized in industrial robot spare parts for ABB, FANUC, KUKA and YASKAWA.
• Cross-reference handled for you: we check whether your machine takes this article or the current number 3HAC039109-002, so an old nameplate does not turn into a wrong order.
• Fitment confirmation before quotation: axis position, robot model and serial number checked against the parts list.
• We can supply the joint gear together with the gearbox oil and seals, so the job is not held up by a missing consumable.
• Quote-based service — send your inquiry with the robot model, serial number, axis and the marking on your existing unit for a matched offer.

Related Products

• 3HAC039109-002 — reduction gearbox for ABB IRB 2600 / IRB 4600 (the current ABB article number for this gear)
• 3HAC039109-004 — reducer for ABB IRB 2600 and IRB 4600 robots
• 3HAC032140-004 — synthetic gear oil for ABB robot joint gearboxes
• 3HAC044361-003 — RV reduction gear for ABB IRB 4600 axis 2
• 3HAC029896-001 — IRB 2600 customer-connection manipulator harness, axes 1-6