HH-YG45-220 Combine Cylinder | 55mm Bore, 45mm Heavy-Duty Rod, 220mm

Model: HH-YG45-220

HH-YG45-220 Combine Cylinder

The HH-YG45-220 is a core-platform combine cylinder in the HH-YG45 series, delivering controlled hydraulic actuation across header positioning and frame adjustment functions on mid-range combine harvesters. With a 55 mm bore, 45 mm rod, and 220 mm stroke, this variant carries a heavier rod specification than its sibling the V90, making it the preferred choice for applications where the cylinder operates under sustained compressive load or where lateral forces are a design concern.

Key Specifications

Bore Diameter55 mm
Rod Diameter45 mm
Stroke220 mm
Mounting Length380 mm

HH-YG45 220 Combine Cylinder: Platform Role and Structural Design Philosophy

The HH-YG45 series represents one of the most widely deployed cylinder families across Chinese-manufactured combine harvesters and their export derivatives. The YG45 designation identifies the mounting and port interface standard; the 220 refers to the 220 mm stroke; and the absence of the V90 suffix (as found on the companion model HH-YG45_220-V90) indicates a different end-cap geometry and pin bore configuration suited to a distinct bracket arrangement.

The most significant engineering distinction between the HH-YG45_220 and the V90 variant is the rod diameter: 45 mm versus 40 mm on the same 55 mm bore. This 5 mm increase may appear minor, but its mechanical consequences are substantial. The cross-sectional area of the 45 mm rod is 15.9 cm² — 26% larger than the 40 mm rod’s 12.6 cm². This additional material provides meaningfully greater Euler buckling resistance across the 220 mm stroke, which is the governing failure mode for piston rods in compressive applications. It also increases the rod’s stiffness against lateral bending, reducing seal wear in installations where the cylinder does not operate in perfect axial alignment with its load path.

In practical combine operation, the mounting geometry of some header bracket designs imposes a small angular misalignment between the cylinder axis and the load vector, particularly when the header pivots relative to the machine frame on uneven ground. The thicker 45 mm rod on the HH-YG45_220 tolerates this misalignment with lower rod seal side-load stress than a thinner rod would experience under the same operating conditions.

The closed length of 380 mm — 5 mm shorter than the V90 at 385 mm — reflects the different bracket geometry this cylinder mounts into. Both cylinders share the same 55/220 bore-stroke combination, but the different closed lengths and end-cap configurations mean they serve distinct machine positions and cannot be substituted for one another without bracket modification.

The HH-YG45_220 is engineered for bracket geometries where sustained compressive load and lateral force tolerance are priority requirements.

Combine Harvester Hydraulic Cylinder OEM Replacement: Choosing Between the YG45-220 and YG45-220-V90

A question that frequently arises when sourcing HH-YG45 series parts is whether the two variants — the standard HH-YG45_220 and the V90 — can be interchanged. The answer is no, for three reasons:

• Closed Length Difference (380 vs 385 mm): A 5 mm difference in pin-centre closed length alters the geometric relationship between the cylinder and its bracket mounting points. In a header lift application, this translates to a changed starting angle for the lift linkage, which affects both the mechanical advantage at the beginning of the stroke and the position of the header at full cylinder retract. Using the wrong closed length results in either incomplete header lowering or mechanical interference at the end of stroke.
• End-Cap Geometry (V90 vs Standard): The V90 suffix designates a specific port location and end-cap profile. Port location governs hose routing — an incorrect port location forces hose rerouting that may not be feasible within the available space on the machine frame, and forced hose bends at the cylinder end create high-pressure fatigue points.
• Rod Diameter (45 vs 40 mm): Although both rods are dimensionally close, they are not pin-compatible with the same gland and bearing bushing. A service technician cannot install a V90 (40 mm rod) replacement into a mounting that expects the standard (45 mm rod) — the rod diameter difference is immediately apparent during installation.

When ordering a replacement, confirm the model number from the cylinder barrel stamp or the machine’s hydraulic parts diagram before purchasing. If the original number is worn or absent, dimensional measurement of the existing cylinder — bore, rod, stroke, closed length — plus a photograph of the end-cap port location allows accurate cross-referencing to the correct variant.

Technical Build Quality: Barrel, Rod, and Seal Specifications for Field-Grade Durability

The HH-YG45_220 barrel is produced from CFS seamless steel tube, drawn to dimensional tolerances of h9 on outer diameter and honed to an internal bore tolerance of H8 with surface roughness Ra ≤ 0.4 µm. This tolerancing ensures that the piston assembly — comprising piston body, wear rings, and PU seal — achieves the designed running clearance without machining adjustment during assembly.

The 45 mm piston rod is cold-drawn steel, centreless ground to h6 tolerance before chrome plating. After chrome deposition (minimum 25 µm thickness, 900–1050 HV hardness), the rod is polished to a final surface finish of Ra ≤ 0.2 µm at the seal contact zone. This finish level is critical: a rougher rod surface micro-abrades the primary seal lip at each extension-retraction cycle, generating seal debris that contaminates the hydraulic fluid and accelerates further seal wear in a self-reinforcing degradation cycle.

The gland assembly uses a triple-element rod seal arrangement: a primary PU lip seal, a secondary back-up seal, and an external dust wiper. The three-element arrangement provides defence-in-depth: if the primary seal develops a minor extrusion flaw from a debris ingestion event, the secondary seal maintains system pressure while the dust wiper prevents further contamination ingress. This redundancy is particularly relevant for combines operating in dusty harvest conditions where a single-seal gland would require more frequent maintenance intervention.

All assembled cylinders undergo hydrostatic pressure testing at 1.5× rated working pressure before shipment, with a hold-and-check procedure that identifies both gross seal failures and slow internal leakage across the piston assembly. Test records are available on request for quality management system compliance.

Supply Terms: HH-YG45 Series Cylinder Procurement for Export Distributors

The HH-YG45 series — including both the standard HH-YG45_220 and the V90 variant — is a high-turnover part number in agricultural aftermarket supply chains serving Southeast Asian, South Asian, Eastern European, and South American combine operators. Distributors stocking this line typically maintain 20–50 pcs per variant as baseline harvest-season inventory, with replenishment triggered at 30% stock level to account for 4–6 week sea freight transit times.

• MOQ for sample qualification: 1 pc per variant, with dimensional certificate and material report supplied.
• Stock order quantities: 10–200 pcs, priced on volume tiers. Mixed-variant orders count toward total volume pricing.
• Export packaging: Individual foam-lined carton with model, bore, stroke, and mounting length marked on exterior for warehouse pick-and-check efficiency.
• Documentation: Commercial invoice, packing list, certificate of origin, and material/test certificate available for all export shipments.

We can work with distributors to build annual supply agreements that lock pricing against raw material fluctuations for the duration of the harvest season planning cycle — typically a 6–12 month forward commitment.

Complete Technical Specifications