Press Fits — validation & limitations

What it calculates

• DIN 7190-1 Lamé contact pressure with GEH (von Mises) hub burst safety factor at the bore
• Shaft crush check on the GEH equivalent stress — for a hollow shaft it is evaluated at the shaft BORE, where the compressive hoop stress concentrates to 2p/(1−(d_i/d)²)
• ISO 286-1:2010 tolerance fit picker — published limit deviations for H7/k6, H7/p6, H7/r6, H7/s6, H7/u6 and more (H-basis, d ≤ 500 mm)
• DIN 7190-1 roughness smoothing correction: effective interference for grip capacity = δ_min − 0.8·(Rz_shaft + Rz_hub)
• Assembly press force and disassembly pull force, with hydraulic oil-injection assist option
• Thermal shrink-fit temperatures — hub heating and shaft cooling required to achieve assembly clearance
• Thermal loosening analysis — residual interference at operating temperature for dissimilar material pairs
• Fretting fatigue safety factor at the hub edge (Goodman criterion under rotating bending)

Standards this tool applies

• DIN 7190 — Core DIN 7190-1 Lamé interference-fit relations — contact pressure, hub burst SF (tool target ≥ 2.0), ISO 286-1 tolerance fit picker, assembly force and thermal shrink-fit temperatures. No centrifugal, conical or stepped-member effects. The fretting fatigue safety factor uses the /fatigue Marin chain, not DIN 7190.

Validation evidence — independent reference cases (1)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

• Press fit pressure, hub burst, shaft crush and torque grip (steel hollow shaft in aluminium hub)

  Agrees

  Source: Budynas & Nisbett, Shigley's Mechanical Engineering Design, 9th-11th ed., Sec. 3-16, Eqs. 3-49/3-50, 3-56, 3-58; Sec. 7-8 / DIN 7190-1 torque capacity

  Inputs: d 40 mm, hub 80 mm, shaft bore 20 mm, L 40 mm, delta 50 um diametral, mu 0.15; hub E 71000 MPa nu 0.33 Sy 250; shaft E 207000 nu 0.29 Sy 400

  Quantity	Reference value	Tolerance
  interface pressure	35.948 MPa	0.01 % relative
  hub burst safety factor	2.9805	0.01 % relative
  hollow shaft crush safety factor	4.1727	0.01 % relative
  torque capacity / safety factor	542.08 N·m / 2.7104	0.01 % relative

  tests/golden/REF-pressfit-lame-two-materials.golden.test.ts

Limitations

Not checked by this tool

• Centrifugal loss of interference at speed — There is no speed input; check high-speed hubs per DIN 7190-1
• Edge pressure and stress concentration at the hub ends — Uniform contact pressure is assumed; for short or stepped hubs use FEA
• Conical (tapered) press fits — Cylindrical joints only; use DIN 7190-2 for conical fits
• Elastic-plastic joints (partial yield of the hub) — Linear-elastic only; a joint designed to yield needs the DIN 7190-1 elastic-plastic method
• Long-term relaxation of the interference (creep, non-ferrous hubs, hot service) — Not modelled; use material creep data
• Room-temperature Sy/E used at operating temperature — The operating-temperature check changes the interference only (α); the yield strength and modulus stay at their room-temperature values — derate Sy and E for hot service from the material data