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[friedolin morgentau]

Hi, i am designing a push-rod connection between a linear actuator and a vehicle brake pedal for a durability test setup. The actuator can apply 750 N, and the pedal rotates through its travel, so the actuator rod sees angular misalignment and dynamic loads. I’m looking to allow this angular change without overloading/wearing the actuator. For high-force pedal actuation like this, what joint or linkage approach works reliably?

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[Wigbert]

The cleanest solution is usually a rod end/Heim joint, mated to a clevis or double-shear bracket > angular freedom without side-loading. Cheap rod ends will loosen. Spec this properly, a high-quality spherical plain bearing, with a real load margin. For 750 N, you’re not near the limits of small rod ends, but shock and misalignment matter, so don’t go light. Mount it in double shear and use proper spacers to avoid bending the shank.

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[HKotelett]

UJs are great for torque transmission; for a push-rod, they’re overkill and won’t appreciate axial cycling. If you need very low backlash, use a spherical bearing housed in a clevis or a cross-pin clevis + spherical washer set. Try to align the actuator rod so it points as close as possible toward the pedal’s attachment point. Or add a short link: actuator > spherical rod end > short link > pedal clevis. The short link swings and keeps the actuator seeing axial load. Hardened shoulder bolts, with properly sized bushings/spacers, lock the fasteners. If you’re sensitive to play, preload the stack with a shouldered fastener and clamp on spacers, not on the joint.

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