Bosch Rexroth Conveyor Questions: Bearings, VFDs, and the Mistakes I Made

I've been handling Bosch Rexroth conveyor and motion component orders for about seven years. In that time I've personally made — and documented — four significant mistakes that cost roughly $5,800. When you make those mistakes on other people's money, you build a checklist fast. I now maintain our team's pre-order checklist so nobody else has to learn the same way.

These are the questions that actually show up in my inbox, plus a few I wish someone had asked me before I ordered the wrong parts.

• What counts as a “Bosch Rexroth conveyor” product?
• Can I use New Hampshire ball bearings on a Bosch Rexroth conveyor?
• Is an Aisin timing belt kit the same as a conveyor timing belt?
• What size VFD do I need for a 5 HP motor?
• Can I use a third-party motor or gearbox with a Bosch Rexroth conveyor?
• What should I check before ordering conveyor or motion parts?

What counts as a “Bosch Rexroth conveyor” product?

When I say Bosch Rexroth conveyor, I mean the modular transfer systems (the TS series), chain conveyors like VarioFlow, and the drive and control packages that run them. It's part of a broader factory automation portfolio that includes ball screws, linear guides, servo motors, actuators, and connecting components.

That distinction matters. A bearing that works in a ball screw assembly isn't automatically right for a conveyor drive pulley, even though both are part of a Bosch Rexroth system. The earlier I know which sub-system the part belongs to, the less likely I am to order the wrong thing.

Can I use New Hampshire ball bearings on a Bosch Rexroth conveyor?

I get this one a lot because New Hampshire Ball Bearings (NHBB) is a respected name in precision bearings. To be fair, they make good stuff. But a good brand isn't the same as a compatible part number.

There are more variables than bore size: radial clearance, contact angle, cage material, seal type, preload class, and lubrication. A bearing can fit on the shaft and still be wrong for the load. In 2019, I ordered a replacement for a support bearing in a Bosch Rexroth linear actuator. The bore matched. The full part number didn't. It ran for three weeks, got louder, then seized. That mistake cost about $1,100 in rework and replacement parts.

If you're looking for New Hampshire ball bearings because you want a local supplier, that's fine. Just order by the full bearing designation, not by a dimensional guess. Granted, that sounds like common sense. It's also the most common mistake on my list.

Is an Aisin timing belt kit the same as a conveyor timing belt?

No. This is a keyword collision that causes real confusion. Aisin is an automotive parts manufacturer, and their timing belt kits are for engine timing systems. A conveyor timing belt is a completely different product.

A colleague once asked if he could use an Aisin kit to replace a worn belt on a packaging line. It sounded plausible because both have teeth. But an automotive timing belt is designed to keep the crankshaft and camshaft synchronized. It isn't built to carry product loads on a Bosch Rexroth conveyor. Different teeth, different reinforcement, different tensioners.

If you searched for “Aisin timing belt kit” and landed here, you're probably looking for a car repair part. If you actually need a conveyor belt, use the belt pitch and width from the conveyor manufacturer. Don't cross-reference by the word “timing.”

What size VFD do I need for a 5 HP motor?

The VFD question I get asked most often is “what size VFD for 5hp motor?” and the short answer is: start with the motor's full-load amps. For a standard 5 HP, 460 V, three-phase motor, NEC Table 430.250 puts full-load current at 7.6 A. A 5 HP VFD is typically rated around 8 A output, so it usually has enough capacity. But that's just the starting point.

What most people don't realize is that the motor nameplate is only half the story. Conveyor load matters. If the conveyor starts under load or sees repeated shock loads, the drive needs headroom. Most VFDs handle 150% overload for 60 seconds, but if you're hitting that repeatedly, you're going to get nuisance trips or worse.

When I first sized a VFD for a 5 HP Bosch Rexroth conveyor motor, I matched the HP, ignored the input power, and skipped the FLA calculation. It ran twice, then tripped. It took me a while to understand that the drive was doing its job; I was feeding it single-phase power. For single-phase input, the usual rule of thumb is to go up to a 10 HP drive for a 5 HP motor. That still feels wasteful every time I order one, but it's cheaper than replacing the drive a second time.

Can I use a third-party motor or gearbox with a Bosch Rexroth conveyor?

Sometimes. The conveyor structure is mostly aluminum framing with standard mounting patterns, so a motor with the right IEC or NEMA frame can bolt up. But the shaft diameter, keyway size, and coupling must match.

I'm not 100% sure how many production delays trace back to a motor that fits the bolt pattern but misses the coupling center height by a quarter inch. The result is vibration, premature seal wear, and a belt that wanders. If you're replacing a servo motor, the situation is different: servo drives expect a specific motor feedback and tuning signature, so a standard induction motor with a servo drive is rarely a drop-in.

Check the dimensional drawing before you buy. If a supplier won't give you one, treat that as a red flag.

What should I check before ordering conveyor or motion parts?

After the first few mistakes, I wrote a short checklist. It's not fancy, but it's caught 47 potential errors in the last 18 months:

• The full OEM part number and revision level
• Motor full-load amps and input power type
• Belt pitch, width, and reinforcement, not just length
• Bearing number including seals, clearance, and preload
• Shaft, keyway, and coupling dimensions
• Whether the part is for a car or for a conveyor

If you're dealing with a Bosch Rexroth conveyor, keep the original part number. The product line changes, and older parts get superseded. As of early 2025, verification is still the cheapest thing you can buy.