What is the recommended installation procedure for a 40mm ID cylinder bushing?

Clean the housing bore to remove burrs and contaminants. Chill the bushing to -20°C for 2 hours to contract the OD by approximately 0.02mm, then press it into the 50mm H7 housing using an arbor press with a flat-faced driver. Apply a light coat of ISO VG 46 hydraulic oil to the bore. After installation, verify that the bushing is flush with the housing face and that the ID remains within 40.000–40.025mm. Do not heat the housing above 80°C, as this may reduce interference. For blind holes, provide a vent hole to avoid hydraulic lock during pressing.

How do I determine if this 40mm bushing is suitable for my cylinder load?

Calculate the maximum radial load on the rod end, then divide by the projected bearing area (40mm × 40mm = 1600mm²). The resulting contact pressure must not exceed 25 MPa static or 15 MPa dynamic. For example, a 30 kN load gives 18.75 MPa, which is acceptable for static but marginal for continuous dynamic use. Also check the PV factor: pressure (MPa) × sliding velocity (m/s) must stay below 2.8. If your application exceeds these limits, consider a wider bushing or a different material such as SAE 64 bronze.

What maintenance intervals are recommended for this bronze bushing?

Under normal hydraulic cylinder operation with clean oil and operating temperatures below 80°C, inspect the bushing every 2000 operating hours or annually. Check for radial clearance increase: replace if the ID exceeds 40.15mm (0.15mm wear). Lubricate with lithium complex grease NLGI 2 every 500 hours if the pivot is not continuously oil-lubricated. In dusty environments, reduce inspection intervals to 1000 hours. The SAE 660 bronze is not self-lubricating under high load; adequate lubrication is required to achieve the rated PV limit.

Cylinder Bushing

40mm ID × 50mm OD × 40mm L SAE 660 Bronze Cylinder Bushing for 25 MPa Hydraulic Systems

This cylinder bushing is a precision-machined sleeve bearing with a 40mm inner diameter, 50mm outer diameter, and 40mm length, manufactured from SAE 660 continuous-cast bronze. It is designed to support radial loads up to 25 MPa static in hydraulic cylinder rod-end and pivot applications.

Length

40mm

Material

SAE 660 Bronze

Static Load Capacity

25 MPa

Surface Roughness

0.08μm Ra

Request A Quote Send E-mail

How to Select the Right Cylinder Bushing for 40mm Shaft Applications

The 40mm ID cylinder bushing is a plain bearing sleeve designed for hydraulic cylinder rod eyes and pivot joints. Its dimensions—40mm bore, 50mm outer diameter, and 40mm length—follow ISO 3547-1 tolerance class F7 for the ID and h6 for the OD, allowing press-fit installation into a 50mm H7 housing. The SAE 660 bronze (UNS C93200) contains 6.5–7.5% tin and 6.5–7.5% lead, which provides conformability and embeddability under shock loads. With a static load capacity of 25 MPa, this bushing suits cylinders operating at pressures up to 25 MPa (3625 psi) with a safety factor of 2. The 0.08μm Ra bore finish reduces wear on chrome-plated piston rods, extending seal life in reciprocating motion.

Typical applications include the rod-end pivot of double-acting hydraulic cylinders in excavators, loaders, and agricultural implements. In these scenarios, the bushing must absorb radial forces from side loading and misalignment. The 40mm bore matches common 40mm piston rod diameters, while the 40mm length provides a bearing area of 1600mm², distributing contact stress to below 15.6 MPa at rated load. This prevents brinelling and fretting corrosion on the rod surface. Unlike thinner bushings, the 1:1 length-to-diameter ratio improves resistance to edge loading when the cylinder is subjected to bending moments, a frequent failure mode in mobile hydraulic systems.

Compared to 30mm or 50mm bore bushings in the same series, this 40mm variant offers a balanced compromise between load capacity and space envelope. The 50mm OD fits standard cylinder eye bores without requiring a larger housing, while the 40mm length is 33% longer than a 30mm bushing, increasing load area by 33% without changing the outer diameter. This makes it suitable for retrofit applications where existing housings are 50mm but higher loads demand more bearing surface. The SAE 660 material also outperforms lead-free alternatives in boundary lubrication conditions, with a maximum PV limit of 2.8 MPa·m/s.

ISO 3547-1 dimensional compliance ensures interchangeability with European and North American cylinder designs.
SAE 660 bronze with 7% tin content provides a hardness of 70 HB, balancing wear resistance and conformability.
Chamfered ends (0.5mm × 45°) and a 0.08μm Ra bore reduce installation damage and shaft wear.

Core Technical Characteristics and Quantified Advantages

STEP 1

SAE 660 Bronze with 7% Tin for Load Capacity

The bushing is cast from SAE 660 bronze (UNS C93200), containing 6.5–7.5% tin and 6.5–7.5% lead. This composition yields a Brinell hardness of 70 HB and a compressive yield strength of 110 MPa. Under a static load of 25 MPa, the safety factor is 4.4 against yield, ensuring no permanent deformation in hydraulic cylinder pivot applications. The lead content provides solid lubrication in case of oil starvation, with a maximum operating temperature of 150°C.

STEP 2

40mm Bore × 50mm OD × 40mm Length per ISO 3547

The dimensions conform to ISO 3547-1: bore 40mm F7, outer diameter 50mm h6, length 40mm ±0.1mm. This allows press-fit into a 50mm H7 housing with an interference of 0.025–0.050mm. The 40mm length gives a bearing area of 1600mm², which at 25 MPa static load results in a contact pressure of 15.6 MPa, well below the material's compressive strength. The 1:1 length-to-diameter ratio improves tolerance to edge loading by 30% compared to shorter bushings.

STEP 3

0.08μm Ra Bore Finish for Reduced Shaft Wear

The inner bore is machined to a surface roughness of 0.08μm Ra (maximum 0.12μm Ra), reducing the friction coefficient against hardened chrome-plated steel to 0.08–0.12. This finish minimizes abrasive wear on the piston rod and extends seal life by up to 40% in reciprocating applications. The outer diameter is ground to 0.4μm Ra for consistent press-fit. Both ends have a 0.5mm × 45° chamfer to prevent O-ring damage during installation.

STEP 4

25 MPa Static Load Rating with 2.8 MPa·m/s PV Limit

The bushing is rated for a static radial load of 25 MPa (3625 psi) and a maximum PV (pressure × velocity) factor of 2.8 MPa·m/s for continuous operation. This allows use in hydraulic cylinders with rod speeds up to 0.5 m/s at 5.6 MPa contact pressure. The rating is based on a 2:1 safety factor against seizure, verified through 500-hour bench tests under 20 MPa load and 0.3 m/s sliding speed at 80°C oil temperature.