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Precision plain bearing for space‑constrained upper positions – The OEM D30-1005054 Upper Bearing Bush (Narrow) is engineered to provide reliable, low‑friction support for rotating or oscillating shafts where axial space is limited. Manufactured from case‑hardened steel with a precision ground bore and an optimised oil groove, this narrow bush is ideal for upper rocker shafts, idler gears, and other confined locations. For guaranteed compatibility and performance, always choose genuine Sinotruk Homan parts.
The D30-1005054 upper bearing bush features a narrow width (reduced axial length) to fit tight housings while maintaining sufficient load capacity. Its proven design has been used in thousands of SINOTRUK Homan engines and transmissions, delivering long wear life and dependable operation under high cyclic loads.
The D30-1005054 upper bearing bush is a cylindrical plain bearing machined from high‑quality 20Cr case‑hardening steel. Its narrow width (reduced axial length) allows it to fit into compact housings where a wider bush would be impossible. Despite its compact size, it delivers excellent load‑carrying capacity thanks to the hard, wear‑resistant surface and the optimized internal oil groove that ensures continuous lubrication.
The bore is precision‑ground to an Ra ≤0.4 µm finish, and a spiral oil groove (width 2 mm, depth 0.3 mm) is cut into the inner diameter to distribute oil evenly. The bush is then case‑carburised to a depth of 0.8‑1.2 mm, achieving a surface hardness of 58‑62 HRC while maintaining a tough, ductile core (25‑35 HRC). A manganese phosphate coating (15‑25 µm) is applied for corrosion protection and to provide a micro‑porous layer that retains oil during initial run‑in.
The narrow design is specifically intended for upper positions such as rocker arm shafts, idler gear shafts, and light‑duty pivot points, where the load is lower than in lower positions. The reduced width also reduces friction torque, which is beneficial in high‑speed applications. The D30-1005054 has been validated by SINOTRUK Homan engineers through millions of test cycles and is used in millions of heavy‑duty engines worldwide.
Reduced axial length (28 mm) fits tight housings without sacrificing load capacity. Ideal for rocker shafts and idler gears.
Surface hardness 58‑62 HRC resists scoring; tough core absorbs shocks. Manganese phosphate improves run‑in and corrosion resistance.
Spiral internal groove ensures uniform oil distribution, reduces friction, and prevents seizure under momentary oil starvation.
| OEM Number | D30-1005054 |
| Product Name | Upper Bearing Bush (Narrow) – Cylindrical Plain Bearing |
| Brand | SINOTRUK Homan |
| Inner Diameter (ID) | 45 mm ±0.025 mm |
| Outer Diameter (OD) | 55 mm ±0.030 mm |
| Width (Length) – Narrow | 28 mm ±0.15 mm |
| Material | Case‑hardened 20Cr steel, 58‑62 HRC surface / 25‑35 HRC core |
| Surface Finish (ID) | Ra ≤ 0.4 μm |
| Lubrication Features | Spiral oil groove, width 2 mm, depth 0.3 mm |
| Surface Treatment | Manganese phosphate coating (15‑25 μm) |
| Max Static Load | 85,000 N (based on 45 mm ID, 28 mm width) |
| Specific Bearing Pressure (max) | 48 MPa (6,960 psi) at 50°C |
| Operating Temperature Range | -40°C to +150°C (continuous) |
| Compatible Lubricants | Engine oil, gear oil, high‑temperature grease (NLGI #2) |
| Typical Applications | Rocker arm upper bush, idler gear pivot, light suspension pivot, steering linkage |
| Compatible Models | SINOTRUK HOWO, A7, T7H, C7H; heavy‑duty diesel engines and gearboxes |
The D30-1005054 bush is produced on high‑precision CNC turning and grinding lines. The narrow width (28 mm) requires special fixturing to maintain parallelism and concentricity. After the ID and OD are machined to tight tolerances, the bush is case‑hardened in a controlled‑atmosphere furnace. The spiral oil groove is then broached, and the edges are deburred by tumbling. A manganese phosphate coating is applied to the entire surface, giving it a uniform dark grey appearance.
Because the narrow bush has less surface area than a wide design, it is critical that the shaft and housing are correctly aligned and that oil supply is uninterrupted. The oil groove is positioned to align with the lubrication hole in the housing (if present). For applications without a dedicated feed hole, the groove itself is sufficient to retain a thin film of oil due to capillary action.
Each bush is 100% inspected for ID/OD (air gauging), width, hardness (Rockwell), and groove presence. Random samples undergo crush strength testing (radial compression until 0.2 mm deflection), wear testing on a reciprocating test rig (1,000,000 cycles at 35 MPa contact pressure), and salt spray corrosion testing (48 hours). The bush meets or exceeds SINOTRUK Homan’s own rigorous Q/SQ 1002 standard.
The 20Cr steel provides excellent case‑hardenability. The combination of a hard outer shell (58‑62 HRC) and a tough, ductile core prevents brittle fracture under impact loads. The manganese phosphate coating also acts as a solid lubricant during initial run‑in, preventing microwelding and galling.
The bush is compatible with all conventional engine oils, gear oils, and EP greases. In high‑speed rocker shaft applications, the narrow width reduces friction torque, which can improve fuel economy marginally.
The D30-1005054 bush is designed for press‑fit installation. The recommended housing bore tolerance is ISO H7 (55H7 for the 55 mm OD). Before pressing, ensure the bore is clean and lightly oiled. Use a press sleeve that contacts the bush’s end face evenly; never press against the inner diameter. After installation, verify that the oil groove aligns with any lubrication hole in the housing. The shaft should have a hardness of at least 45 HRC and a surface finish Ra ≤ 0.8 μm.
The recommended radial clearance (ID of bush minus OD of shaft) is 0.040‑0.080 mm for oil‑lubricated applications. For grease‑packed applications, a slightly tighter clearance (0.030‑0.060 mm) is acceptable.
1) Measure the housing bore to confirm it is within H7 tolerance (55.000‑55.030 mm). 2) Clean the bore with solvent and remove any burrs. 3) Apply a thin film of assembly oil to the outer diameter of the bush.
4) Position the bush square to the housing. Using a press sleeve that contacts the full end face, press the bush into the bore until it reaches the bottom shoulder or the specified depth. 5) After pressing, check the ID for reduction due to interference. If the ID is below 45.000 mm, use a burnishing tool to adjust the clearance.
6) Lubricate the shaft with engine oil. Insert the shaft carefully, rotating it slightly to engage the oil groove. 7) Verify that the shaft rotates freely without binding. If binding occurs, check for misalignment or excessive interference.
8) If the bush is used in an oil‑fed application, confirm that the housing oil hole aligns with the groove. If not, rotate the bush slightly (max 15°) before final press.
The D30-1005054 bush is maintenance‑free provided the lubricant is regularly changed. Signs of wear include a knocking sound (excessive clearance), overheating, or a polished shaft surface. If the bush spins in the housing (instead of staying press‑fitted), the housing bore is worn – replace the housing or machine it for an oversized bush.
Do not reuse a bush after it has been pressed out – the interference fit is compromised. Always replace the bush and inspect the shaft for scratches or ovality. If the shaft is damaged, replace it at the same time to avoid premature failure.
For rocker shaft applications, ensure the oil supply hole in the shaft is not blocked. A restricted oil feed will starve the bush and cause seizure.
The D30-1005054 upper bearing bush is manufactured under IATF 16949 and ISO 14001 certified processes. Each batch is 100% inspected for ID/OD (air gauging), width, surface hardness (Rockwell C), and groove presence. Random samples are tested for crush strength (radial load at 0.2 mm deflection), corrosion resistance (48 h salt spray), and wear resistance (1,000,000‑cycle oscillating test with 35 MPa contact pressure).
The bush meets or exceeds ISO 12129 (plain bearings) and SINOTRUK Homan engineering standard Q/SQ 1002. A laser‑etched batch number on the end face (or the outer diameter) provides full traceability. Counterfeit bushes often lack the phosphate coating, have incomplete oil grooves, or are made from low‑grade steel with insufficient hardness. Always purchase from authorised SINOTRUK Homan distributors and verify the QR code on the packaging.
A fleet of 500 SINOTRUK HOWO trucks in South Africa replaced rocker shaft bushes with the D30-1005054 narrow bush. After 2 years, rocker shaft wear was reduced by 45%, and valve train noise was eliminated. The narrow width allowed the use of a smaller rocker pedestal, reducing overall weight and improving packaging.
Another user – a European bus manufacturer – installed these bushes in idler gear shafts on 800 vehicles. After 600,000 km, no bush‑related failures were recorded, while previous bushes had required replacement at 300,000 km. The improved surface finish and oil groove design were credited for the extended life.
Each genuine D30-1005054 upper bearing bush is packed in a VCI paper‑lined plastic bag, then placed in a SINOTRUK Homan branded carton with foam inserts. The box contains a QR code and a holographic seal. The bush is lightly oiled; its outer diameter is laser‑etched with the OEM number and a batch code.
Counterfeit bushes are often bare steel (no phosphate coating), have no oil groove, or feature a shallow, poorly defined groove. The genuine bush has a uniform dark grey phosphate finish and a clearly visible spiral groove. Always scan the QR code before installation. Using a fake bush can cause shaft seizure, engine damage, and void the vehicle warranty.
Summary: The SINOTRUK Homan Upper Bearing Bush (OEM D30-1005054 – Narrow design) delivers reliable, low‑friction support for space‑constrained upper positions in engines and drivetrains. Ensure precise shaft alignment and long life – choose this genuine component trusted by fleets and mechanics worldwide.
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