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TIO PROMKompozit
Specifications

Hydraulic cylinder specifications and dimensions

Choosing a cylinder by outside size alone is not enough: bore, rod diameter, stroke, working pressure and mounting geometry are calculated together.

Main dimensions

Main hydraulic cylinder dimensionsDimension lines: D — barrel bore, OD — barrel outer diameter, d — rod diameter, S — stroke, L₀ — retracted length, L₁ — extended length.L₁— extended lengthL₀— retracted lengthS— strokeDØ120–350 mmODØ150–440 mmdØ80–270 mm
  1. 1D — Barrel bore — Ø120–350 mm
  2. 2OD — Barrel outer diameter — Ø150–440 mm
  3. 3d — Rod diameter — Ø80–270 mm
  4. 4S — Stroke — Full extension travel of the rod
  5. 5L₀ — Retracted length — Pin-to-pin length with the rod fully in
  6. 6L₁ — Extended length — Pin-to-pin length with the rod fully out, L₁ = L₀ + S
DimensionSymbolMeaning
Barrel boreDInside diameter the piston runs in
Barrel outer diameterODOutside diameter of the cylinder tube
Rod diameterdOutside diameter of the rod
StrokeSFull extension travel of the rod
Retracted lengthL₀Pin-to-pin length with the rod fully in
Extended lengthL₁Pin-to-pin length with the rod fully out, L₁ = L₀ + S
Working pressurePWorking pressure of the hydraulic system
Mounting dimensions—Sizes of eyes, flanges, clevises and pins

Manufacturing and repair ranges

Rod diameter
Ø80–270 mmChosen for force, buckling risk, stroke length and mounting conditions.
Barrel bore
Ø120–350 mmBore accuracy and finish are critical for seal performance.
Barrel outer diameter
Ø150–440 mmChosen to match the bore, wall thickness and strength calculations.

Wall thickness

The difference between the outer and inner diameter gives the nominal wall thickness:

t=OD−D2t = \frac{OD - D}{2}

For example, a barrel with a 440 mm outer diameter and a 350 mm bore has a nominal wall thickness of:

t=440−3502=45 mmt = \frac{440 - 350}{2} = 45\ \text{mm}

This is a geometric calculation: the actual minimum wall, machining allowance and strength are checked separately.

Stroke

Stroke is the distance the rod travels from fully retracted to fully extended. It follows from the mechanism geometry and is specified in the order. For long strokes, buckling risk, side loads and mounting conditions are calculated separately.

Working pressure

Working pressure depends on the cylinder design, dimensions, materials, seals and test results. For example, the ISO 6020 family provides 16 MPa (160 bar) series and ISO 6022 provides 25 MPa (250 bar) series. This does not mean all cylinders share the same pressure.

How much force does a cylinder produce?

Theoretical force depends on pressure and the effective piston area:

F=P⋅AF = P \cdot A

Where F is force (N), P is pressure (Pa) and A is the effective piston area (m²).

Theoretical extension force — pressure acts on the full piston area:

Fext=P πD24F_{\text{ext}} = P\,\frac{\pi D^2}{4}

Theoretical retraction force — pressure acts on the annular area:

Fret=P π(D2−d2)4F_{\text{ret}} = P\,\frac{\pi \left(D^2 - d^2\right)}{4}

D is the piston (bore) diameter and d is the rod diameter. Real force is lower because of friction, back pressure and system losses.

On extension pressure acts on the full piston area (πD²/4); on retraction it acts on the annular area (π(D² − d²)/4).
Extension: A = πD² / 4On extension pressure acts on the full piston area (πD²/4); on retraction it acts on the annular area (π(D² − d²)/4).ExtensionA = πD² / 4DPFFull areaForce F
Retraction: A = π(D² − d²) / 4On extension pressure acts on the full piston area (πD²/4); on retraction it acts on the annular area (π(D² − d²)/4).RetractionA = π(D² − d²) / 4DdPFAnnular areaForce F

Worked example

Piston diameter 200 mm, rod 120 mm, working pressure 250 bar. Theoretical extension force ≈ 78.5 tonne-force, retraction ≈ 50.3 tonne-force (taking 1 tf ≈ 10 kN). This is a mathematical example, not a certified load rating.

Enlarging the rod alone does not raise force: the main factors are piston diameter and working pressure. The rod is sized for pulling force, buckling and structural loads.

Force calculator

Extension force
≈ 78.5 tonne-force785 kN
Retraction force
≈ 50.3 tonne-force503 kN

Theoretical value: friction and losses not included; 1 tf ≈ 10 kN.

Materials

Material choice directly affects a cylinder’s service life, strength, wear resistance and safety.

  • Rod steel

    Steels with the required mechanical properties, good machinability and, where needed, heat treatment and hard chrome. Examples: C45/1045, 42CrMo4/1.7225.

  • Barrel steel

    Material suited to pressure, tube deformation and bore accuracy requirements. Example: 17G1S or similar steels, depending on the order.

  • Seal materials

    NBR, FKM, polyurethane (PU) and PTFE are chosen by pressure, temperature, fluid and duty. No single material suits every condition.

For BelAZ mining trucks and cranes, material selection takes into account load cycles, impact, rod buckling, pressure, ambient temperature, corrosion and existing drawings. A steel grade alone does not guarantee a reliable part.

Frequently asked questions

What does cylinder force depend on?

Mainly on oil pressure and the effective piston area. Extension and retraction forces differ because the rod area is subtracted on retraction.

Which steel is best for the rod?

It depends on load, diameter, stroke and heat-treatment requirements. Steels such as C45 or 42CrMo4 are considered against the technical requirements.

Why does the bore diameter matter?

It sets the piston area, and therefore the force and oil volume. Bore finish also affects seal life.

Do all cylinders use the same oil?

No. Oil type is chosen for the system requirements, temperature, materials and seal compatibility.

Does your hydraulic cylinder need repair, or do you need a new one?

Send the machine model, main dimensions and a description of the fault — our specialist will contact you to agree on the scope of work and next steps.

+998 88 644 74 74+998 99 331 00 74