4722648 Original Excavator Needle Brg for ZX130-7

Part number 4722648 is the original needle roller bearing provided by Hitachi for the ZX130-7 series hydraulic excavator (with a total working weight of approximately 13 tons). This component is mainly used for key parts such as rotating mechanisms, walking reducers, or hinge points of working devices that bear high radial loads and have limited installation space. Its universal models usually cover 12-14 ton same platform models such as ZX120-7, ZX135-7, ZX140-7, etc. The image you uploaded shows a needle roller bearing of NTN brand, model HL-4A-8E-NK, with dimensions of 30 × 42 × 20, which is likely to be consistent with the physical dimensions of Hitachi original part 4722648. However, please note that although the dimensions may be interchangeable, genuine original parts have been specially optimized for Hitachi equipment in terms of material, heat treatment, tolerance fit, and grease. To ensure optimal performance and lifespan, it is strongly recommended to use original parts.

This product is a needle roller bearing without an inner ring and with a cage, and its structure is exactly the same as the picture you provided. Its inner diameter is 30mm, outer diameter is 42mm, width is 20mm, and the needle roller diameter is about 3mm. The outer ring material is high carbon chromium bearing steel, and the needle roller and holder are precision machined and heat-treated to ensure high load-bearing capacity and rotational accuracy. The maximum speed is high and can withstand significant radial impact loads. It saves space by directly using hardened and ground shaft necks as raceways. The bearing in the picture is open type, and the original parts may be equipped with rubber sealing rings for dust and water resistance depending on the installation position. The working temperature range is generally from -30 ℃ to+120 ℃.

Installation points: 1 Check the dimensions and tolerances of the shaft and bearing seat holes. The shaft diameter tolerance is usually H5, the seat hole tolerance is H6, and the surface roughness Ra is ≤ 0.8 μ m; Before installation, all mating surfaces must be cleaned and an appropriate amount of lubricating grease must be applied to the shaft neck; 3. Use a dedicated installation sleeve or core shaft to smoothly and vertically press the bearing into the seat hole. It is strictly prohibited to directly strike the bearing end face or needle roller. Lubrication management: Sufficient high-quality extreme pressure lithium based grease should be filled during installation. Add lubricating grease through the oil nozzle every 250 working hours until the old grease is squeezed out from the sealing edge.