Product Video
Products Description
|
Brand |
Product Name |
Model |
Part Number |
|
Hitachi |
Sprocket | EX1800 | 4451622 |
Product Details
|
Product Name |
Sprocket |
|
Part Number |
4451622 |
|
Origin |
Japan |
|
Brand Name |
HItachi |
|
Model |
EX1800 |
|
Price |
Negotiable |
|
Packing Details |
Standard Export Packing |
|
Delivery Time |
0-30 Days |
|
Payment Term |
L/C, T/T |
|
Price Term |
FOB, CIF, CFR |
|
Supply Capacity |
50,000 PCS/Month |
|
Minimum Order Quantity |
1 PC |
|
Material |
High Quality Steel |
|
Technology |
Precision Machining |
|
Quality |
Original Factory Standard |
|
After-Sales Service |
Full Support, Online Service |
|
Color |
Customizable |
|
Application |
Excavator |
|
Customizable |
including customized materials, surface treatment and specifications |
Product Features
Technical Specifications
Height (mm): 390
Width (mm): 1470
Length (mm): 1470
Weight: 330–340 kg (727–750 lbs)
Material: Cast Steel
Chain Pitch Compatibility: 317 mm or 350 mm
Max Torque Transmission: Up to 1,500 kN·m
Color: Black
Segments that match the wear state of the chain
Each tooth segment is produced to the same profile specification as the original, so when a segment is replaced, the new tooth matches the remaining segments on the same hub and maintains consistent engagement with the existing chain pitch. This prevents a situation where one new segment runs at a different engagement depth than the others, which would cause uneven load distribution and accelerated wear on that segment.
Tooth profile that remains functional throughout the chain wear cycle
The Drive Sprocket's tooth profile maintains effective contact with the bushing over a wider range of pitch change as the chain pitch gradually elongates with use. This allows the sprocket to continue delivering traction force without the tooth tip digging into the bushing or losing contact prematurely. The engagement stays functional from the time the chain is new to when it reaches the recommended replacement point, rather than only during the first half of the chain's life.
Segments that do not require selective matching during installation
Each segment is manufactured within a consistent dimensional tolerance band, so any segment from the same production batch fits any mounting position on the hub without requiring selective sorting or trial fitting. Installation time is reduced because no time is spent matching segments to specific positions.
Segments that allow partial replacement of the sprocket
When only one or two segments are worn, they can be replaced individually. The remaining segments stay in place, and the new segments match the existing ones without requiring a full set change. This avoids the cost of discarding segments that still have service life remaining.
Application Value
Track hesitates when starting from a stop after prolonged idling
The machine has been idling for a while. The operator engages travel, and instead of responding immediately, the track seems to pause, then lurches forward. This is not a hydraulic issue-it is the chain bushing sitting in a worn spot on each tooth. After idling, the bushing settles into the deepest part of the worn tooth face. The first rotation has to climb the bushing out of that worn spot before normal engagement begins. That climb takes torque that does not result in movement.
Machine wanders during straight-line travel without steering input
On level ground, with the travel levers fully forward, the machine does not hold a straight line. It drifts gently to one side, requiring constant steering correction from the operator. The track alignment is correct. The undercarriage is symmetrical. The drift is caused by one side of the sprocket having more tooth wear than the other. The worn side has a smaller effective rolling radius, so it takes more revolutions to cover the same distance. The machine turns toward the slower side.
Sharp turns produce a metallic clicking sound not present in normal operation
During tight turns on hard ground, a metallic clicking sound comes from the track area. The sound is rhythmic and increases with track speed. Normal operation does not produce this sound. It is the Drive Sprocket teeth contacting the chain bushings at an angle different from what the tooth profile was designed for. The misalignment causes the tooth tip to strike the bushing edge instead of engaging through the intended contact face. The sound is a warning.
Maintenance Recommendations
Decide whether to replace a segment based on wear distribution
If all segments on the same hub show similar wear levels, replacing one segment early will cause load imbalance-the new segment carries more load because it has more tooth height, accelerates its own wear, and forces adjacent segments to run at different engagement depths. The correct approach is to assess the hub as a set. If one segment reaches the wear limit but the others still have at least two-thirds of their remaining life, replace all segments on that hub at the same time. The cost of replacing one slightly worn segment early is lower than the cost of replacing two segments later.
Check whether the remaining service life of the chain justifies replacing segments
Before ordering new segments, measure the chain pitch at three points along its length. If the average pitch elongation has already exceeded 1.5% of the original specification, replacing segments alone will not restore proper engagement. The chain bushing center distance has already changed, and the new tooth profile will not align with the worn bushing spacing. In that case, the chain should be replaced before the segments. Installing new segments on a stretched chain accelerates wear on both components.
Record Drive Sprocket Segment Installation Date And Hour Meter Reading
After fitting new segments, note the installation date and machine hour meter value. Log this information in the maintenance record. When wear is later measured, the hours accumulated will show the actual service life achieved under that specific site condition. Without this record, replacement decisions are based only on visual appearance, and wear progression cannot be tracked. Over time, this log becomes the basis for adjusting replacement intervals based on actual site data rather than generic manufacturer recommendations.
Inspect the condition of the hub face after removing worn segments
After the old segment is removed, the hub face often shows compacted debris, light corrosion, or minor surface damage from previous segment movement. Before fitting a new segment, clean the hub face with a scraper or wire brush, then wipe it with a clean cloth. This allows the new segment to sit fully flush against the hub face. A segment that sits on debris will eventually shift under load, creating the same pattern of movement that caused the original damage. The cleaning step takes less than a minute per segment and prevents the cycle from repeating.
STONE
Stone is a leading supplier of engineering machinery parts, focusing on providing high-quality parts for mining companies. Since its establishment in 2004, we have been based in Shanghai, China, and have built our own brand STONE, becoming a trusted choice in the industry. We are committed to providing a variety of parts including bulldozers, excavators and wheel loaders for well-known brands such as Caterpillar and Komatsu. Our product line covers a full range of OEM parts, such as Track Chain, Track Rollers, Sprocket, Excavator Buckets, Blades, Excavator Cylinders, Swing Circles, and various electrical and hydraulic components to ensure that our customers' stringent requirements for quality and performance are met.
quality
years experience
service
hours warrant
Q＆A
Do I have to replace the mounting bolts every time I change sprocket segments?
Yes. The mounting bolts on the EX1800 sprocket are torque-to-yield bolts. Each time they are tightened to specification, they stretch slightly and do not return to their original length. Reusing them means they cannot achieve the correct clamp force, and the segment will shift under load, leading to bolt fatigue and eventual shearing. Always use new bolts with each segment replacement. The cost of new bolts is minimal compared to the labor cost of extracting a snapped bolt from the hub.
At what point should sprocket teeth be considered beyond serviceable condition in the field?
If the tooth face shows a visible hook on the Drive Sprocket side and the tooth tip has formed a sharp peak on the trailing side, the segment has reached its wear limit. As a simpler field rule: if the tooth tip width is less than half the original width, replacement is due. If the tooth surface still shows a flat contact area with no hooking, the segment can continue running. The key distinction is whether the tooth profile still maintains a flat contact area where the bushing engages, or if it has worn into a hook shape and peak shape.
Can sprocket segments from the EX1200 be installed on the EX1800 undercarriage?
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