{"id":2434,"date":"2026-06-30T08:59:20","date_gmt":"2026-06-30T08:59:20","guid":{"rendered":"https:\/\/hydrauliccylindersprice.com\/product\/excavator-oil-cylinder\/"},"modified":"2026-06-30T08:59:30","modified_gmt":"2026-06-30T08:59:30","slug":"excavator-oil-cylinder","status":"publish","type":"product","link":"https:\/\/hydrauliccylindersprice.com\/ja\/product\/excavator-oil-cylinder\/","title":{"rendered":"Excavator Oil Cylinder"},"content":{"rendered":"

<\/p>\n

<\/p>\n

\n
\n
\n Construction Equipment<\/span>
\n Excavator \u00b7 Boom \u00b7 Arm \u00b7 Bucket<\/span>\n <\/div>\n

Break Rock at 35 MPa.
Grade a Slope to \u00b110 mm.
Same Three Cylinders.<\/h2>\n

The tractor cylinder (#35) lifts implements. The turnover plow cylinder (#36) flips a plough. The excavator cylinder does everything \u2014 digging trenches, loading trucks, demolishing buildings, grading roads, laying pipes, and lifting steel. Three cylinders (boom, arm, bucket) form a kinematic chain that gives the operator millimetre-level control over a bucket that can rip through frozen ground. The highest working pressure in the outdoor equipment family.<\/p>\n

\n
\n
25\u201335MPa<\/span><\/div>\n
Working Pressure<\/div>\n<\/div>\n
\n
3 Types<\/div>\n
Boom \u00b7 Arm \u00b7 Bucket<\/div>\n<\/div>\n
\n
4\u20136<\/div>\n
Cylinders per Machine<\/div>\n<\/div>\n
\n
3\u20135\u00d7<\/div>\n
Shock Load Factor<\/div>\n<\/div><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Three Cylinders, One Kinematic Chain \u2014 Boom, Arm, Bucket<\/h2>\n

The excavator’s front-end is a three-link kinematic chain: the boom pivots at the machine body, the arm pivots at the boom tip, and the bucket pivots at the arm tip. Each joint is powered by its own cylinder \u2014 and every motion of one cylinder changes the geometry of the other two. The operator moves all three simultaneously to trace the bucket along a precise path through the soil.<\/p>\n

\n
\n
Boom Cylinder (\u00d72)<\/strong><\/div>\n
\n

Raises and lowers the entire front-end. The largest cylinder on the excavator \u2014 highest bore diameter, longest stroke. Carries the combined weight of the boom, arm, bucket, and payload. Operates in pairs (one on each side of the boom) to provide balanced lifting force without twisting the boom structure.<\/p>\n<\/div><\/div>\n

\n
Arm (Stick) Cylinder (\u00d71)<\/strong><\/div>\n
\n

Extends and retracts the arm \u2014 controlling the reach distance and the digging depth. The arm cylinder determines how far from the machine the bucket can reach (up to 10 metres on large excavators) and how deep it can dig (up to 7 metres). Single cylinder, centred on the boom.<\/p>\n<\/div><\/div>\n

\n
Bucket Cylinder (\u00d71)<\/strong><\/div>\n
\n

Curls and opens the bucket \u2014 the digging tool. The bucket cylinder produces the “breakout force” that tears soil and rock from the ground. The highest pressure cylinder in the chain \u2014 operating at full system pressure (25\u201335 MPa) during hard digging. Single cylinder with a link mechanism that amplifies the curl force.<\/p>\n<\/div><\/div>\n<\/p><\/div>\n

Korea Ever-Power manufactures all three excavator cylinder types as part of the construction and industrial cylinder range<\/a>.<\/p>\n<\/section>\n

<\/p>\n

\n \"Excavator
\n<\/section>\n

<\/p>\n

\n
\n

Shock Loading \u2014 The Excavator Hits Things It Cannot See<\/h2>\n

Every other cylinder in this catalogue works on known loads \u2014 a mold of known weight, a platen of known dimension, a tire of known mass. The excavator bucket digs into ground where the operator cannot see what lies below the surface. Buried boulders, concrete foundations, steel pipes, tree roots, and frozen soil all produce sudden, massive force spikes when the bucket hits them.<\/p>\n

\n
\n Impact magnitude: 3\u20135\u00d7 working load<\/strong><\/p>\n

When the bucket strikes a buried boulder, the kinetic energy of the moving arm and bucket is absorbed in milliseconds \u2014 creating a pressure spike in the bucket and arm cylinders that can reach 3\u20135\u00d7 the normal working pressure. The cylinders, their seals, the barrel welds, and the pin joints must all survive these spikes without failure. Korea Ever-Power designs excavator cylinders with pressure safety margins above the relief-valve setting.<\/p>\n<\/p><\/div>\n

\n Unpredictable frequency<\/strong><\/p>\n

A tractor cylinder sees predictable loads \u2014 the plough weight is constant. An excavator cylinder sees random shock loading that varies with every bucket-load. Digging in sandy soil: minimal shocks. Digging in rocky ground: shocks on every third or fourth bucket curl. Demolition: continuous shock from breaking concrete. The cylinder must handle all these patterns without cumulative fatigue failure.<\/p>\n<\/p><\/div>\n

\n Rod side-loading during offset digging<\/strong><\/p>\n

When the excavator digs at an angle (not straight-on to the target), the bucket reaction force has a lateral component that pushes the cylinder rod sideways \u2014 creating a bending moment on the rod and uneven seal loading. Excavator cylinders use oversized rod bearings and reinforced barrel bottoms to handle this chronic side-loading without premature seal wear. Contact the hydraulic cylinder engineering team<\/a> for excavator cylinder specifications.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Power and Precision \u2014 The Excavator’s Impossible Duality<\/h2>\n
\n \"Excavator<\/p>\n

At 10 am, the excavator rips through frozen clay at full system pressure \u2014 the bucket cylinder producing 150+ KN of breakout force. At 2 pm, the same machine grades a drainage slope to \u00b110 mm over a 20-metre run \u2014 the boom cylinder making incremental adjustments measured in fractions of a millimetre.<\/p>\n

This duality \u2014 maximum force and fine precision from the same cylinder \u2014 demands two things that are normally contradictory: high stiffness (for force) and low friction (for precision). High stiffness means tight tolerances and rigid mounting; low friction means smooth seals that respond proportionally to small valve inputs without stiction (stick-slip).<\/p>\n

Korea Ever-Power achieves both: the bore is honed to Ra 0.2 \u00b5m (the fine end of the range) for low seal friction; the rod bearing is oversized for stiffness under side loading; and the seal compound is selected for low breakaway force \u2014 the force needed to start the cylinder moving from a standstill. Low breakaway force means the operator can make the small, controlled movements that precision grading demands.<\/p>\n<\/p><\/div>\n

<\/div>\n<\/section>\n

<\/p>\n

\n

Construction Site Survival \u2014 Harder Than the Farm<\/h2>\n
\n \"Excavator<\/p>\n

The tractor cylinder (#35) faces soil and weather. The excavator cylinder faces everything the tractor does, plus concrete dust, welding spatter, demolition debris, and salt water (marine construction). The rod is continuously coated with a film of abrasive mud that the wiper seal must scrape clean before the rod retracts into the bore.<\/p>\n

Chrome plating is 50\u201380 \u00b5m minimum. Rod wipers are triple-lip with a hardened steel scraper ring \u2014 heavier than tractor specification. External hose ports use O-ring face seal (ORFS) fittings rather than tapered threads \u2014 providing leak-free connections that survive the constant vibration of excavator operation. The barrel is painted with a two-part epoxy that resists stone chips and chemical splash.<\/p>\n

Operating hours are extreme: a construction excavator runs 2,000\u20135,000 hours per year. At 6\u201310 full boom cycles per minute during active digging, the boom cylinders alone complete 1\u20133 million pressure cycles per year \u2014 approaching the fatigue duty of indoor industrial cylinders but in a far harsher environment.<\/p>\n<\/p><\/div>\n

<\/div>\n<\/section>\n

<\/p>\n

\n

Manufacturing \u2014 High Pressure, High Shock, High Volume<\/h2>\n

\"Korea<\/p>\n

The excavator cylinder barrel is thicker-walled than a tractor cylinder at the same bore \u2014 designed for 25\u201335 MPa continuous duty with shock spikes to 50+ MPa. Barrel welds are full-penetration and ultrasonically inspected \u2014 weld fatigue under shock loading is the primary structural failure mode for excavator cylinders. The rod is induction-hardened at the piston-end thread zone (where shock bending loads concentrate). FKM seals are optional for tropical and high-temperature applications; NBR is standard for temperate climates. Every excavator cylinder is hydrostatic tested at 1.5\u00d7 rated pressure and random-sample shock-tested \u2014 applying repeated pressure spikes at the relief-valve setting to verify barrel, weld, and seal integrity under the excavator’s actual operating conditions.<\/p>\n<\/section>\n

<\/p>\n

\n

OEM & ODM<\/h2>\n
\n
\n
\n

What You Provide<\/h3>\n<\/div>\n
\n

Excavator model and operating weight class (mini, midi, standard, large), cylinder function (boom\/arm\/bucket), bore, rod, stroke, system pressure, pin-to-pin dimension, pin diameters, port size and thread standard (ORFS\/BSP\/SAE), and the front-end assembly drawing showing cylinder mounting positions and the linkage geometry.<\/p>\n<\/div><\/div>\n

\n
\n

What the Factory Delivers<\/h3>\n<\/div>\n
\n

Engineering drawing with bore, rod (shock-rated, induction-hardened thread zone), stroke, barrel wall thickness (calculated for shock duty at 1.5\u00d7 relief setting), triple-lip wiper + scraper, chrome plating \u226550 \u00b5m, ORFS ports, and pin dimensions. Hydrostatic test + shock-cycle test (random sample). Seal kits. Browse the complete construction and industrial cylinder range<\/a> and the full hydraulic cylinder product catalogue<\/a>.<\/p>\n<\/div><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

FAQ<\/h2>\n
\n
\n

Why does the excavator operate at higher pressure than the tractor?<\/h3>\n

Because the excavator must produce higher force density \u2014 more force from a given cylinder size. The excavator’s boom, arm, and bucket must fit within the machine’s front-end envelope (limited by stability and visibility), but must produce enough force to dig through hard soil and rock. Higher system pressure (25\u201335 MPa vs the tractor’s 16\u201321 MPa) allows smaller-bore cylinders to produce the required forces \u2014 keeping the front-end compact enough for the operator to see around it.<\/p>\n<\/p><\/div>\n

\n

Can Korea Ever-Power supply a matched set (boom + arm + bucket) for a specific excavator model?<\/h3>\n

Yes \u2014 provide the excavator model and the existing cylinder dimensions (or the original part numbers). Korea Ever-Power manufactures the complete front-end cylinder set as a coordinated order, ensuring all cylinders are built to the same pressure rating, seal specification, and chrome plating standard. Matched-set orders also simplify spare parts management and seal kit inventory on the job site.<\/p>\n<\/p><\/div>\n

\n

How does the excavator cylinder compare to the forklift cylinder?<\/h3>\n

Both are mobile equipment cylinders, but the excavator operates at much higher pressure (25\u201335 MPa vs 16\u201321 MPa), faces random shock loading (the forklift loads are predictable), and has heavier environmental protection (triple-lip wipers vs double-lip). The forklift cylinder range<\/a> is designed for the cleaner, lighter-duty material handling environment. Browse telescopic cylinders<\/a> for dump truck and trailer applications.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Related Categories<\/h2>\n
\n <\/p>\n
\n
\"Telescopic\"<\/div>\n
\n
Telescopic Hydraulic Cylinders \u2192<\/div>\n
Dump truck, trailer, hoist.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"Forklift\"<\/div>\n
\n
Forklift Hydraulic Cylinders \u2192<\/div>\n
Lift, tilt, steer \u2014 OEM.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"AWV\"<\/div>\n
\n
Aerial Work Vehicle Cylinders \u2192<\/div>\n
Scissor, boom, platforms.<\/div>\n<\/div>\n<\/div>\n

<\/a>\n <\/div>\n<\/section>\n

<\/main><\/p>","protected":false},"excerpt":{"rendered":"

Excavator oil cylinder \u2014 the hydraulic cylinders that power the excavator’s front-end kinematic chain: boom, arm (stick), and bucket. Three cylinder types, linked in series, produce the digging, lifting, grading, and demolition motions that make the excavator the most versatile machine on any construction site. Working pressure 25\u201335 MPa \u2014 the highest in the outdoor equipment family. The bucket cylinder curls through rock; the arm cylinder reaches 10 metres; the boom cylinder lifts 5 tonnes. And the same three cylinders that break concrete must also grade a slope to \u00b110 mm. Korea Ever-Power. ISO 9001. OEM & ODM.<\/div>","protected":false},"featured_media":2435,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[852],"product_tag":[],"class_list":["post-2434","product","type-product","status-publish","has-post-thumbnail","product_cat-industrial-engineering-hydraulic-cylinders","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product\/2434","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/comments?post=2434"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media\/2435"}],"wp:attachment":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media?parent=2434"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_brand?post=2434"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_cat?post=2434"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_tag?post=2434"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}