Procedures for Operation / Assembly and Disassembly of Hydraulic Cylinder

1.Specifications and Structure Diagram (including the assembly diagram and parts table)

This manual explains the KCH-6 model construction machine hydraulic cylinder, which has a structure typical of such cylinders.

For details on the specifications and structure of the product being used, see the delivery diagram (including the assembly diagram and parts table) given separately. 2.Operation Explanation (1) Basic functions Hydraulic cylinders are a type of hydraulic actuator. A hydraulic cylinder converts the energy of pressure supplied from the hydraulic pump into a large force of linear motion. By operating the hydraulic pressure direction switchover valve, one can switch the direction of operation between extension and retraction. This linear motion with large force and the switchover of the operation direction are the basic functions. (2) Function of each location This manual explains the functions of each section of the cylinder using one of our products with a typical structure. There may be some slight differences with the product being used, but the functions are the same. 1)Cylinder head assembly The cylinder head assembly has the function of bearing the piston rod (2) by the bushing (4) press fit into the interior diameter of the cylinder head (3). The seal system of the interior diameter of the cylinder head prevents oil from leaking to the outside and prevents foreign matter from getting into the cylinder. The cylinder head assembly also has the function of supplying and discharging high-pressure oil from inside the cylinder tube to the retraction side port.

•Bushing

Press fit to the inside surface of the cylinder head (3) and contacts the piston rod (2). Together with the slide rings (18) and (19) on the outer circumference of the piston, the bushing divides the lateral load applied to the cylinder and moves linearly relative to the piston rod. Furthermore, it supports one end of the piston rod and has the function of minimizing eccentricity which has a negative impact on the sealing. •Buffer ring

The buffer ring (6) has the function of buffering the pressure and heat applied on the U-ring (7) by the hydraulic oil to improve durability.

1 Cylinder tube 2 Piston rod 3 Cylinder head 4 Bushing 5 O-ring 6 Buffer ring 7 U-ring 8 Backup ring 9 Wiper ring 10 O-ring 11 Backup ring 12 Installation bolt

•U-ring and backup ring

The U-ring (7) seals the pressurized oil within the cylinder. The U-ring also has the function of forming an appropriate oil film on the surface of the piston rod in order to prevent rust of the piston rod (2). The backup ring (8) has the function of suppressing extrusion of the U-ring into the gap between the piston rod and the cylinder head (3) when the pressure operates and of improving durability. •Wiper ring

The wiper ring (9) is positioned in the opening where the piston rod (2) comes out from and goes into the cylinder and prevents dust and water from getting into the cylinder from the outside. It also has the function of wiping off any mud sticking to the surface of the piston rod as the piston rod moves. 2)Piston assembly

The piston assembly has the function of transmitting the propulsion of the cylinder. A seal ring (16) is mounted on the center of the piston (15) to prevent the flow of pressurized oil from either the left or right chamber to the other chamber. There are slide rings (18) and (19) mounted at each end of the seal ring. They have the function of a bearing to receive the cylinder lateral load.

1 Cylinder tube 2 Piston rod 13 Cushion ring 14 Cushion seal 15 Piston 16 Seal ring 17 Backup ring 18 Slide ring 19 Slide ring 20 Locking screw 21 Steel ball 22 Cushion ring 23 Cushion seal 24 Stopper 25 Snap ring

For some cylinder sizes, the piston (15) and nut (21) are separate.

Example of parts numbers for separated piston and nut •Seal ring and backup ring

The seal ring (16) is positioned at the center of the piston (15) and uses the tension force of the O-ring to seal the ring-shaped gap between the piston and the cylinder tube (1) and form chambers with a high-pressure side and a low-pressure side with the piston as the boundary.

The backup ring (17) has the function of suppressing extrusion of the seal ring into the gap between the piston and the cylinder tube when the pressure operates and of improving durability. •Slide ring

Slide rings are positioned at both ends of the seal ring (16) and contact the inside surface of the cylinder tube (1). Together with the bushing (4) positioned on the inside surface of the cylinder head (3), the slide ring divides the lateral load applied to the cylinder and moves linearly relative to the inside surface of the cylinder tube.

Furthermore, it supports one end of the piston rod (2) and has the functions of minimizing eccentricity, which has a negative impact on the sealing, and buries and captures any impurities trapped between the cylinder tube and the slide rings (18) and (19). •Cushion ring

When the cylinder is fully extended, the cylinder head (3) and the cushion ring (13) fit together.

When it is fully retracted, the cylinder bottom and the cushion ring fit together. In both cases, this forms a ring-shaped gap and squeezes the oil to reduce the cylinder collision speed at full extension or full retraction and thus soften the impact.

1 Cylinder tube 2 Piston rod 13 Cushion ring 14 Cushion seal 15 Piston 16 Seal ring 17 Backup ring 18 Slide ring 19 Slide ring 20 Shim 21 Nut 22 Locking screw 23 Steel ball 24 Cushion ring 25 Cushion seal 26 Stopper 27 Snap ring

3)Pipe assembly

The pipe assembly is mounted on the extension side and retraction side ports of the cylinder tube assembly. It has the function of supplying and discharging high-pressure oil by connecting with the hydraulic circuits of the machine body.

28Pipe assembly 29Pipe assembly

3.Handling Precautions (1) Precautions for installing the cylinder on the machine body •When installing the cylinder on the machine body or removing it from the machine body, secure the piston rod at the fully retracted position, check safety, and suspend.

•Do not weld after the cylinder has been mounted on the machine body.

•When painting the machine body, mask the piston rod and wiper ring.

•Clean the cylinder before installing it.

(2)Usage cautions •Use under the determined conditions.

•Warm up the equipment adequately before work.

Caution Never suspend the cylinder from the line section. This would not only pose the danger of falling but could also damage the cylinder. Use a band to secure the piston rod in the fully retracted state. If the piston rod is not in the fully retracted state, it could be easily damaged. This could create the need for repair or make the piston rod unusable. Also, not securing the piston rod is dangerous because the piston rod might fly out unexpectedly.

Caution Electric welding on the cylinder or even at a position separated from the cylinder can generate a spark within the cylinder and damage parts. This could cause extensive damage, making it necessary to replace parts or replace the cylinder.

Caution If the cylinder is operated with paint sticking to the piston rod surface and the wiper ring, the wiper ring does not function adequately, greatly interfering with cylinder functions. For example, dirt and paint from the outside may get into the cylinder easily and damage seal parts and cause an oil leak.

Caution Use of hydraulic oil other than that specified can cause rapid deterioration of and damage to seal parts. If the relief valve is set to a value higher than that on the assembly diagram, there is a danger of this leading to cylinder damage. General sealing materials cannot handle high ambient temperature (about 100 ℃ or higher) or low ambient temperature (-20 ℃ or lower), so the cylinder would be damaged if used at such temperatures. Such temperatures require special seal materials, so check if the cylinder being used complies with this requirement. The number one cause of cylinder trouble is oil leaks due to piston rod scratches. Operate very carefully to avoid scratching the piston rod. If the piston rod is scratched, handle this according to "5. Trouble Diagnostics".

Caution After the cylinder has been stopped for a long time, the seal parts inside the cylinder are stuck to the metal of sliding surfaces, so do not suddenly pressurize or operate such a cylinder. A new cylinder or one that has been left unused for a long time has much air built up inside, so it does not operate smoothly. Also, if one suddenly operates or pressurizes the cylinder without bleeding out the air, the adiabatic compression of the air generates high temperatures, which may burn and carbonize seal parts, leading to a drastic drop in functioning. Before starting work, always warm up the cylinder by moving slowly through a few full strokes under no load to bleed off any air in the cylinder.

•Always put the machine in a safely secured posture when stopping it temporarily or storing it.

(3)Maintenance and inspection cautions •Always carry out daily maintenance inspections.

•Use genuine KYB parts for replacement parts.

•Be careful about assembly and disassembly too.

•Strictly observe the cylinder storage standards.

Caution When extended, the cylinder cannot hold a load for a long time in a fixed position. This is because the cylinder is extended and retracted by very minor oil leaks from hydraulic circuits and from inside the cylinder and changes in the volume of the hydraulic oil due to oil temperature variation. This results in the danger of machine moving unexpectedly, which can lead to serious accidents. Always put the machine in a safely secured position before stopping it temporarily or storing it.

Caution The most important point for realizing the cylinder functions for a longer time is "daily maintenance inspections". In order to ensure adequate cylinder functioning, execute "4. Maintenance Inspection and Service". Constantly clean off any mud, water, dust, oil or grease stuck to the piston rod and keep the piston rod in a clean state. However, do not use water or the like to clean the wiper ring section and seal section. Wipe with a rag. When leaving the machine unused for a week or longer, apply anti-rust oil to the surface of the piston rod in order to prevent rusting.

Caution If replacement parts are used that are not genuine KYB parts, adequate functioning cannot be attained. Always use genuine KYB parts. Specialty jigs have been produced so that assembly work and disassembly work can be done safely and quickly, so order them.

Caution Disassembling a cylinder still installed on the machine body is extremely dangerous because it can cause unexpected movement of the machine body. Always remove the cylinder from the machine body before disassembling it. Assembling with dirty hands can get dirt inside the cylinder and not only reduce the cylinder service life but also damage other hydraulic equipment. Assemble under clean conditions. Use the thread part tightening torque indicated in the diagram. If the torque is either too low or too high, this can cause thread damage.

Caution Execute according to "7. Assembly and Disassembly Procedures".

4.Maintenance Inspection and Service

In order to ensure a hydraulic cylinder functions properly for a long time, periodically carry out maintenance inspection and service based on the "Autonomous inspection table". Repair any trouble locations quickly based on the trouble diagnostics.

Caution For periodic inspection and service, first work to prevent any hazard to operators. Strive to prevent hazards by working with an attitude based on good sense.

Inspection and service location Inspection and service detail Daily Monthly Yearly Remarks

Appearance Is the cylinder clean (especially rod sliding sections)? Is any oil leaking from line installation sections or other fixed sections?

Operation Is there missing or peeling paint, or rust? ○ Is operation smooth and free of abnormal noise and any other abnormality? ○

Is the responsiveness good?

○ Is any oil leaking from sliding sections? ○ Are there internal leaks?

Is the pressure used normal? Is the overload relief valve set pressure normal?

Hydraulic oil

Main unit installation section

Piston rod section

Cylinder tube section (including line sections) Are there any loose bolts or nuts (threaded parts)?

Is hydraulic oil dirty or deteriorated? Is hydraulic oil replaced periodically? Are filters inspected periodically? Is the supply of grease to pins adequate? Do pin sections have any abnormal noises or seizing? ○

Do pin sections have any backlash or wear? ○ Are pin seals normal? Are any installation screws loose or fallen out? ○ Retighten installation screws. Are sliding sections worn? Are sliding sections scratched or dented? ○ Is sliding section plating peeling off? ○ Are sliding sections bent? Are there any welding section cracks or damage?

Retighten threaded installation parts (bolts and nuts (threaded parts)). Are there any welding section cracks or damage? Are there large dents on the tube? When leaving piston rod sliding sections exposed for long periods, apply antirust oil to the piston rod.

5.Trouble Diagnostics

Hydraulic cylinder trouble, countermeasure and solution

It is not easy to discover trouble locations. The table below shows general symptoms, suggested causes and also solutions.

For repairs, see the possible causes and solutions in the table.

The cause of machine problems are often not rooted in just a single part. Problems are often due to the relationship of one part with another. In some cases, solutions are required other than those given in the table. In such a case, contact with our company to investigate the problem and its cause further and take appropriate measures. Item Symptom 1 Piston rod sliding section oil leak (For the judgment values, see "7. (4) Inspection after assembly".) 2 Cylinder head matching section oil leak 3 Pipe and cylinder tube welding section oil leak 4 Operation defect

Item Symptom Related part Symptom

Piston rod A sliding surface has rust and scratches that catch on a fingernail.

1 Piston rod sliding section oil leak Plating is peeling off.

There is foreign matter caught in the interior or exterior diameter section.

There are scratches on the interior or exterior diameter section.

Rod packing (Buffer ring and U-ring) The lips and groove section are locally carbonized (scorched).

The packing has lost its rubber elasticity and is in tatters.

The lip section is defective all the way around.

There is major extrusion of the packing heel section.

Backup ring The part is greatly deformed. Countermeasure and solution ① Remove the scratches with a whetstone to make the sliding surface smooth (1.5 s max.). If the oil leak continues, the rod scratches may have damaged the U-ring or other seal, so disassemble and inspect. ② If the scratches or rust cover too large an area to be repaired with a whetstone, replace the piston rod and the U-ring, wiper ring, or other seal and the piston rod bearing part. ① Replate or replace the piston rod. ② At this time, inspect the seals and piston rod bearing part as well and replace any that are damaged. ① Remove the foreign matter. ② If the packing is damaged, replace it.

Replace the part.

① This may be scorching due to adiabatic compression of air remaining in the cylinder. ② When operating the cylinder for the first time after replacing a packing, run at low pressure and low speed to adequately bleed off the air. ① Replace the part. ② This may be the end of the packing service life, deterioration of the hydraulic oil, or high temperature of the hydraulic oil. a. Replace the hydraulic oil. b. Check the temperature of the hydraulic oil. (The oil temperature should be no higher than 80 ℃ .) c. Check for local high temperature. ① Replace the part. ② Abnormally high pressure may be operating on the packing. a. Check the pressure during operation. b. There may be trouble with the buffer ring section. Inspect the buffer ring section. ① As a rule, replace the rod packing too at the same time. ② Abnormally high pressure is often the cause. The check items for this are the same as those given above for packing heel section extrusion.

Item Symptom Related part Symptom Countermeasure and solution

1 Piston rod sliding section oil leak Wiper ring

Bearing part (bushing) There is foreign matter caught in the lip. Remove the foreign matter. The lip is damaged. There is other abnormal damage. Replace the part.

There is major wear of the bushing and the gap with the piston rod exceeds the limit on interior diameter wear in "8.-(9) Usage limits". Replace the part.

There are large scratches on a sliding surface. ① Replace the part. ② Inspect the piston rod sliding surfaces for scratches and rust.

2

3 Cylinder head matching section oil leak

Pipe and cylinder tube welding section oil leak

Oil leak from cylinder line connection section Cylinder head A seal mounting section has scratches and rust.

O-ring There is foreign matter caught in the interior or exterior diameter. There is damage to the O-ring.

Backup ring The part is deformed or extruded. ① Remove the scratches or rust with a whetstone. ② If the repair does not solve the problem, replace the cylinder head. ① Remove the foreign matter. ② If the O-ring is damaged, replace it. ③ Tube interior surface inspection: If there are any scratches or rust, use a whetstone to make the surface smooth. ④ Cylinder head O-ring groove inspection: Same as above ⑤ Backup ring inspection: If the backup ring is deformed or extruded, replace it. Check the above and replace the O-ring.

Replace the backup ring together with the O-ring.

Cylinder head A part is loose.

① Disassemble the cylinder head and inspect the O-ring and backup ring. If there is damage, replace. ② Check the tube and cylinder head threads for damage and if there is any damage, replace. ③ When the inspection is complete, tighten to the specified torque. See "7. (7) Assembly procedure". ④ Stop rotation. Bolt There is looseness, stretching or breakage. Replace all the bolts and tighten to the specified torque.

Cylinder tube There is abnormal swelling. ① Replace with a new one. ② Oil leaks at matching sections may be caused by abnormally high pressure (including cushion pressure), so if the tube is swollen or deformed, replace it with a new one. Also inspect the circuit pressure.

Pipe and cylinder tube

Pipe assembly There are cracks on the welding section.

Line fastening bolt is loose. Replace with a new one.

Caution (See page421.)

The crack progresses and ultimately the part fractures. A fracture is extremely dangerous, so if a crack is seen, quickly stop work and replace that part. Welding over a crack is ineffective.

Tighten to the specified torque according to the work procedure.

The line is bent. Replace with a new one. There are scratches on a contact surface. ① Use a whetstone to make the surface smooth. ② If the oil leak does not stop, replace.

Item Symptom Related part Symptom Countermeasure and solution

Operation defect Movement is not smooth. Piston rod Cylinder tube The bending is large and exceeds the stipulated bend warp. (Bend warp: See "7. (3) Maintenance standards".) ① Replace with a new one. ② There may also be damage to seals and sliding parts, so inspect them. If there is any abnormality, replace.

Cylinder tube There are dents. Replace with a new one. Inspect the seal and sliding parts the same as above.

Piston rod Cylinder tube Sliding parts Abnormal wear of sliding parts and damaged piston section or foreign matter caught at the cylinder head sliding section ① Replace with a new one.

Inspect the seal and sliding parts the same as above. ② Remove the foreign matter.

Inspect the seal and sliding parts the same as above.

4 Internal oil leak The piston rod extends and retracts on its own and drops abnormally during operation. Also, the stipulated speed is not output. Piston seal There are scratches, wear, or other damage.

Cylinder tube There are scratches and rust on interior surface. Replace with a new one. Also inspect the cylinder tube interior surfaces. ① Use honing or a whetstone to eliminate the scratches and rust and make the surface smooth. If the scratches cover too large an area to be repaired, replace the cylinder tube with a new one. ② Replace with a new piston seal.

Piston nut Tightening is insufficient.

① Tighten to the specified torque.¢7.-See "7. - (7) Assembly procedure". ② The piston rod thread section could be stretched. Measure the diameter where the rod and piston fit together and if this area is tapered, replace the piston rod assembly. Valves Leak from valve. Inspect the amount of valve leakage and service.

Operation is unsteady. Air There is air remaining in the cylinder. Bleed out the air. a. Cylinder with no air bleeding

Bleed out the air by moving the cylinder back and forth at few times at low pressure and low speed. b. Cylinder with air bleeding (air breather)

After securing the machine so that the cylinder does not move, bleed the air from the air breather. [Tip]

The cylinder extends or retracts somewhat when the cylinder stops suddenly. This phenomenon occurs due to the compressibility of the hydraulic oil. This occurs particularly easily for cylinders with long strokes.

The impact is high when switching over between extension and retraction. Pin bushing Pin The gap between the installation section and the pin bushing is enlarged. Measure the pin and pin bushing dimensions and replace any part that exceeds its stipulated dimension.

Cylinder sliding operations make sounds. Pin bushing Pin The oil or grease feed is inadequate. Apply oil or grease. There is galling at matching section. Replace with a new part and apply oil or grease.

Caution

The hydraulic oil expands and contracts with changes in temperature and pressure. This causes the cylinder to extend and retract too, so it can be mistaken for an internal oil leak. For internal oil leaks, always check the temperature and pressure under the same conditions.

6.Storage Standards

When a hydraulic cylinder is shipped from the plant, every measure is taken, but in order to prevent trouble during storage and to extend the product service life, pay attention to the following items. 1)Storing the cylinder alone (In principle, store indoors.) •Store the cylinder off the floor and do not store in any location with high temperature and humidity, corrosive gas or liquids. •Before shipment, we operates the cylinder with hydraulic oil to which a fixed quantity of vaporizing anti-rust agent has been added (in order to prevent rust within the cylinder), carries out the pre-shipping inspection, then retracts the piston rod with ultra-dry air (condensation point -35 ℃ or lower) (in order to prevent condensation due to temperature difference), and then puts caps on the ports and line joints before shipping the cylinder. •Any product that has been storage in our product warehouse longer than the standard storage period is disassembled and inspected before being shipped. Therefore, do not store or leave a cylinder unused with a cap removed or with the remaining oil in the cylinder drained.

2)Mounted on vehicle body

3)Recommended anti-rust oil

① Storage for one month or longer Storage for six months or longer (3 months for cylinder alone) Storage for one year or longer

Clean any dust from the cylinder, and then apply anti-rust oil to the pin bushings, flange sections, piston rod, and other sections that rust easily. Operate the cylinder back and forth with clear hydraulic oil, and then pour anti-rust oil into the cylinder and store in compliance with the items on the left for storage of one month. Since there is a danger of packing deterioration, disassemble, inspect, and replace packings. Also, check for rust inside the cylinder.

② If the cylinder cannot be operated, seal in anti-rust oil.

If a cylinder that has been stored for a long time is used as is, oil may leak due to temporary running-in defects of seals. ③ When storing a cylinder, be extremely careful not to drop it, let it collide with anything, strike it.

① Operate the cylinder at least once per month ② Retract the cylinder so that as much as possible outside air does not touch the piston rod and apply anti-rust oil at least once per month to the exposed part of the piston rod. ③ Handle carefully to absolutely avoid scratching the piston rod. ④ When putting the cylinder into an environment where rust occurs particularly easily, for example due to exposure to sea breezes during export, always apply anti-rust oil to the piston rod and as much as possible protect with polyethylene sheets or VCI paper (vaporizing anti-rust paper). ⑤ Anti-rust oil and other solvents can have negative impacts on seals, so select anti-rust oil carefully and as much as possible keep it off dust seals etc. (For details on anti-rust oil to select, see "6.3) Recommended anti-rust oil".)

For inside cylinder

Vaporizing anti-rust oil a. Ferro Gard #1009 (from USC Limited) a. Knuckle Oil #105S (from Parker Industries, Inc.) For both a. and b., add 3 % - 5 % of the hydraulic oil. By volume, Ferro Gard: 5/100 Knuckle Oil: 3/100 For piston rod Anti-rust P-1300 (from the Nippon Oil Corporation) For machine worked surfaces other than parts with oil sealed in Select from JIS K 2246 (anti-rust oil) NP-1 through NP-6.

7.Assembly and Disassembly Procedures (1) Preparations ・・・・・ Prepare the following before starting disassembly. [1] Work platform preparation Prepare a sufficiently spacious, solid and stable work surface so that parts will not fall or move during work. [2] Tool and materials preparation Prepare the tools and materials shown on the following pages. (2) General work precautions [1] Clean any dirt or mud from the outside walls of the cylinder before starting disassembly. [2] Each part has been manufactured with a high degree of precision, so be careful not to let parts bump each other or fall when handling them. [3] If parts are struck or pulled with excessive force during work because they are tight, this may cause burrs or damage which causing reduction in performance or oil leaking. Perform work carefully and thoroughly. [4] If a cylinder is left disassembled, humidity and dirt can cause rust on parts. If a pause in the work is unavoidable, be careful to prevent rust and keep off dust. (3) Maintenance standards Replace sliding parts and seal parts as follows. [1] BushingWhen 1/4 of the circumference is worn brown over the entire length [2] Seals and slide ringsReplace with new parts when the cylinder is disassembled. [3] Pin bushingWhen there is drastic galling [4] Piston rodWhen the piston rod is bent more than 0.5 mm/1 m

(4)Inspection after assembly Dimension inspection Check the fully retracted length and stroke as instructed on the diagram. Pressure withstand inspection Check for looseness, permanent deformation, and external leaks when the test pressure instructed on the diagram is applied to each stroke end for at least 3 min. Check the amount of oil leak at the rod section. ・ Judgment value for rod section oil leak Move the piston rod back and forth 20 times with the oil at a temperature from 20 ℃ to 40 ℃ , and then judge by the state of the oil ring formed on the rod surface. If the oil ring is in a broken down A state, this is judged to be trouble. See "5. Trouble Diagnostics" for information on how to solve this.

External leak inspection

Internal leak inspection Oil leak unit: ml/10 min.

Interior diameter mm Oil leak amount Interior diameter mm Oil leak amount Interior diameter mm Oil leak amount

32 0.4 160 10.0

40 0.6 100 4.0 180 12.6

50 1.0 125 5.6 200 15.6

63 1.6 140 6.0 220 20.0

80 2.3 250 22.0

(5)Required tools 1)General tools

No. Tool name

1 Screwdriver (flathead screwdriver)

2 Hexagon wrench

3 Vise

4 Wrench (for piston nuts)

5 Punch

6 Torque wrench

7 Hammer (plastic hammer)

8 Monkey wrench

9 scoop Q'ty

1

1 set

1

1 set

1

1 set

1

1

1 set

2)Special jig

Cylinder assembly requires the following special jigs.

Consult with our company about jigs. (The following page has a list of jig part numbers.)

Jig name

For bushing removal and press fitting Sketch

For wiper ring press fitting

Seal ring insertion jig

Seal ring calibration jig

For cylinder head insertion

For piston insertion

3)Special jigs part number list [1] Select jigs for the cylinder head according to the rod diameter. [2] Select jigs for the piston according to the cylinder bore.

Cylinder head assembly and disassembly jig Applicable rod diameter Set part number 65 3006J-56001 70 3007J-06001 75 3007J-56001 80 3008J-06001 85 3008J-56001 90 3009J-06001 95 3009J-56001 100 3010J-06001 105 3010J-56001 110 3011J-06001 115 3011J-56001 120 3012J-06001

Seal ring insertion and calibration jig Applicable cylinder bore Set part number 95 3009J-51001 100 3010J-01001 105 3010J-51001 110 3011J-01001 115 3011J-51001 120 3012J-01001 125 3012J-51001 130 3013J-01001 135 3013J-51001 140 3014J-01001 145 3014J-51001 150 3015J-01001 160 3016J-01001 170 3017J-01001

(6)Disassembly procedure 1)Drain the oil. 2)Secure the cylinder.

Secure the cylinder in a vertical or horizontal position. A vertical position makes assembly and disassembly easier. Secure the cylinder using the bottom pin hole and stop rotation and secure the axis position. (When securing the cylinder, if a line or the like interferes, remove it.)

3)Removal of cylinder head

Use a hexagon wrench to loosen the cylinder head tightening bolts and remove them.

Passing a pipe through the hexagon wrench as in the diagram below makes the work easier.

4)Pull out the piston rod. [1] Check that the line caps are removed. [2] Put the oil pan at the retraction side (cylinder head side) port. [3] With the piston rod pulled out all the way, slowly pull out the cylinder head and remove it. [4] Pull out the piston rod together with the cylinder head and place them on crossties.

5)Secure the piston rod.

Use the rod head bolt width or pin hole to set up a rotation stopper.

Caution ・ When assembling and disassembling with the cylinder secured vertically, work paying particular attention to the following points.

In the work of removing the piston rod, the cylinder head may come out of the cylinder tube ahead of the piston due to friction with the packing, creating a condition in which there is space between the cylinder head and the piston.

If the work is done in that state, the cylinder head may suddenly slip out and injure the operator. Always work with the cylinder head touching the piston.

Working in the vertical state

Caution ・ When assembling and disassembling with the cylinder secured horizontally, work paying particular attention to the following points.

In the work of removing the piston rod, there is a danger of the piston rod falling and damaging parts right after it is removed.

Work carefully while holding the rod horizontal and in contact with the crossties.

6)Remove the piston nut. [1] Remove the locking screw (3). Locking screw is caulked in with a punch at 2 locations on the outer circumference. Cut away the caulked sections with a hand drill, and then loosen the locking screw.

[2] Remove the steel ball (2) at the bottom of the locking screw (3).

[3] Remove the piston nut. •The piston nut is tightened with the torque specified in the assembly diagram. •Loosening a piston nut requires about 1.5 times that torque. Prepare the power wrench (6) that uses the hydraulic jack (4) and hydraulic cylinder (5). * For a one piece piston and nut, apply the wrench to the hexagonal section of the piston and loosen the piston directly.

7)Removal of piston etc.

Remove the piston (9), cushion ring (8), and cylinder head (7) in that order.

1 Drill 2 Steel ball 3 Locking screw 4 Hydraulic jack 5 Hydraulic cylinder 6 Wrench 7 Cylinder head 8 Cushion ring 9 Piston

8)Retraction side cushion ring disassembly

[1] Remove the piston nut. The cushion ring cannot be disassembled with the piston nut attached. [2] Remove the snap ring (12). Remove by gently tapping with a plastic hammer in such a way as to not scratch the piston rod (11) or cushion ring (14). [3] When the cushion ring (14) is slid to the piston rod thread (11) side, the stopper (split in two) (15) can be removed. [4] Remove the cushion ring (14). [5] The cushion seal (13) has a split opening, so spread the opening wide and remove the cushion seal.

9)Remove the piston seal. [1] The slide rings (22) and backup ring (20) can be removed easily by hand. [2] Stand up a flathead screwdriver (23) as in the diagram on the right and tap with a hammer to cut through the seal ring (16), and then remove the seal ring. [3] Pull out the O-ring (19) with a scoop. * The removed seal parts cannot be reused.

10 Screw 11 Piston rod 12 Snap ring 13 One cushion seal split opening 14 Cushion ring 15 Stopper (split in two) 16 Seal ring 17 Piston 18 Vise 19 O-ring 20 Backup ring 21 Hardwood 22 Slide ring 23 Screwdriver

10)Disassembly of buffer ring [1] The buffer ring (27) is mounted in the groove on the interior diameter of the cylinder head. When removing this seal, stick in a sharp tool and lift it up, and then insert a scoop and take it out. * The removed seal parts cannot be reused.

11)Disassembly of U-ring and wiper ring [1] Use a screwdriver to remove the U-ring (26) and backup ring (25). [2] The wiper ring (24) is press fit. Stick a screwdriver straight down into the rubber and tap it to remove the wiper ring. * The removed seal parts cannot be reused.

12)Removal of O-ring and backup ring [1] Pull out the O-ring (29) and backup ring (30) with a scoop.

13)Disassembly of bushing [1] Raise the snap ring (28) with a screwdriver, and then remove it from the cylinder head. [2] For the bushing (33), use the bushing removal jig (32) as in the diagram on the right and press out the bushing with a press.

24 Wiper ring 25 Backup ring 26 U-ring 27 Buffer ring 28 Snap ring 29 O-ring 30 Backup ring 31 Bushing 32 Bushing removal jig 33 Bushing

14)Removal of pin bushing [1] Remove the wiper ring (24) from the tube and piston rod. Remove it by using a screwdriver in the same manner as for the cylinder head. [2] Use the metal block (35) to remove the pin bushing (37).

15)Cleaning and storage

Clean the removed parts with white kerosene, and then apply hydraulic oil, cover the parts, and store them.

If they are left disassembled, there is a danger of their collecting rust and dust and not being able to function adequately after they are assembled again.

34 Press 35 Metal block 36 Jig 37 Pin bushing

(7)Assembly procedure

1)Installation of pin bushing [1] Use the installation jig to press fit onto the piston rod (4) and into the tube. (Apply hydraulic oil in advance.) [2] Use the metal block (5) to install the wiper ring (6).

2)Replacement of seal [1] When reassembling the cylinder, replace all the seals. [2] O-rings •Clean the mounting groove well, and then mount the backup ring (7) and O-ring (8). Foreign matter in the grove section would cause an oil leak. •Be careful about the location of the backup ring. •Apply grease or hydraulic oil to the backup ring and O-ring so that they slide easily, and then assemble them. If they are sliding poorly, O-ring may become twisted during assembly, which causes oil leaks.

Caution If a part with peeling paint is assembled, the peeled off paint can get inside the cylinder. This causes oil leaks, so work being very careful to prevent this.

1 Press 2 Installation jig 3 Pin bushing 4 Piston rod 5 Metal block 6 Wiper ring 7 Backup ring 8 O-ring 9 Cylinder head

3)Assembly of cylinder head assembly [1] Use the bushing press fit jig (10) to press fit the bushing (11). Apply hydraulic oil to the inside surface of the cylinder head in advance and after press fitting, check that there is no level difference at the bushing. [2] Use the wiper ring press fit jig (15) to press fit the wiper ring (16). [3] Mount the backup ring (18) and U-ring (19) in the U-ring groove (17) in that order. •Check the assembly direction of the U-ring and mount it carefully so as not to scratch it. Installing the U-ring backwards would cause an oil leak. •After mounting, check that there are no wrinkles or other permanent deformation remaining in the U-ring.

[4] Mount the buffer ring (20).

Be careful with the attachment directions of the seals.

If the seal is installed backwards, extraordinarily high pressure will be generated between the seal and the U-ring (19), causing deformation and breakage of the cylinder. [5] Assemble the bushing retainer snap ring (21).

10 Jig 11 Bushing 12 Cylinder head 13 Pressing base 14 Press 15 Wiper ring press-fit jig 16 Wiper ring 17 U-ring groove 18 Backup ring 19 U-ring 20 Buffer ring 21 Snap ring

4)Assembly of piston assembly [1] Assemble the seal ring (24). •Assemble the back-up ring (23) for one side and the O-ring (25) on the piston (26) in advance, place on the press platform, and use the seal ring insertion jig (22) as in the diagram to assemble the seal ring. [2] Correct the seal ring. •Mount the seal ring (24) and the other backup ring (23), and then immediately correct with the seal ring calibration jig (27) so that the seal ring does not remain expanded. (Strictly observe this instruction.) Since the seal ring is stretched when it is mounted, if it is not calibrated, "6) Insertion of piston rod into the tube" is not possible. [3] Assemble the slide ring. •Spread the cut section of the slide ring the minimum with both hands and install from the axial direction. If it is spread too wide, it cannot be mounted. * Consult with our company about jigs.

5)Assembly of piston rod assembly [1] Secure the piston rod (31). [2] Assemble the cylinder head (32) on the piston rod (31). Be careful that the wiper ring and U-ring lips do not catch on the stepped section. Use the cylinder head insertion jig (30) as in the diagram on the right to assemble the cylinder head on the piston rod. •Apply grease or oil and assemble being careful not to scratch the packing.

22 Seal ring insertion jig 23 Backup ring 24 Seal ring 25 O-ring 26 Piston 27 Seal ring calibration jig 28 Metal block 29 Press 30 Cylinder head insertion jig 31 Piston rod 32 Cylinder head

[3] If there is a cushion on the extension side, assemble the cushion ring (33) and cushion seal (34) with the following procedure. 1) Insert into the groove with the side of the cushion seal with the slit (*2) facing the piston side. 2) Assemble with the part of the cushion ring processed to be flat facing as in the diagram.

[4] When there is a cushion on the retraction side

Assemble the cushion ring (39) and cushion seal (38) with the following procedure. 1) Assemble the cushion ring before assembling the piston nut. The cushion ring cannot be assembled with the piston nut attached. 2) Mount in the groove with the side of the cushion seal with the slit (*4) facing the thread side. 3) Assemble with the part of the cushion ring processed to be flat facing as in the diagram below. 4) Insert the stopper (40) into the groove. Press the cushion ring (39) all the way to the stopper and strike in the snap ring (37). Strike gently with a plastic hammer in such a way as to not scratch the piston rod (4) or cushion ring.

*1 Flat surface processing *2 Face the slit to the flat side. *3 Face the slit to the thread side. *4 Slit side 4 Piston rod 33 Cushion ring 34 Cushion seal 35 Piston 36 Thread 37 Snap ring 38 Cushion seal 39 Cushion ring 40 Stopper (split in two)

Caution Make sure that the cushion seal and cushion ring face the correct direction. If they are installed backwards, the cushion will not be effective. After installing the cushions, check that the extension and retraction cushion rings move up and down and left and right.

[5] Tighten the piston nut. •Always tighten the piston nut to the specified torque given on the assembly diagram. •If the tightening torque is insufficient, this causes internal leaks, nut looseness, and thread cutting •Also, if the tightening torque is excessive, extension side cushion ring swelling and piston contact surface deformation occur. •In order to tighten correctly, clean and degrease the piston and nut and piston rod thread section adequately (with paint thinner) before tightening the nut. [6] Stop the piston from turning. •After tightening the piston nut, put in the steel ball (43), tighten the locking screw (42) to the specified torque given on the assembly diagram, and then caulk (41) with the punch (44) at 2 locations on the outer circumference.

6)Insertion of piston rod into the tube [1] Secure the tube (47) vertically or horizontally. [2] Insert the piston rod (4) into the tube (47). •If the tube is secured vertically, the piston rod enters the tube due to its own weight. •When the piston section is entering the tube, be careful that the slide rings (46) do not fall out.

4 Piston rod 41 Caulking 42 Locking screw 43 Steel ball 44 Punch 45 Jig (nylon pipe (split in two)) 46 Slide ring (Shift the abutment phase 180 珵 rom one ring to the next.) 47 Tube

7)Cylinder head tightening

Align the cylinder head with the position on the assembly diagram, and then tighten the bolts to the specified torque given on the assembly diagram in the order shown in the diagram below.

8)Installation of line [1] Check that the O-ring is in the groove correctly. [2] Tighten the port section bolts to the specified torque given on the assembly diagram. [3] Tighten the bands for securing the line to the torque on the assembly diagram, the same on both sides, so that no abutment gap occurs.

(8) Test operation [1] In order to fill the inside of the cylinder with oil, after it is installed on the machine body, move the cylinder through its full stroke slowly 8 times or more. If the cylinder is suddenly moved from the start, the hydraulic oil may be aerated. [2] If the cylinder has air bleeding, pressurize so that the air bleed side is the pressure side (return oil side) and bleed off the air. [3] Apply oil and grease to the pins at both ends.

Bolt tightening order

*5 Tighten the bolts. *8 Normal: OK *6 Be careful about the O-rings. *9 There is a gap: Not OK *7 No abutment opening gap *10 Band for securing the line

Caution When installing the cylinder lines and the machine body rubber hoses, nipples, etc., assemble securing the cylinder line port section with a wrench. If one tightens without securing the port section, the line may bend, oil may leak, and the machine body may get in the way.

(9)Usage limits

Below are the usage limits for sliding sections. Use them for reference for maintenance. •Piston rod exterior diameter wear limit

•Rod bushing interior diameter wear limit

•Piston slide ring thickness wear limit

Nominal diameter (mm) 65 ～ 80

85 ～ 120 Minimum outer diameter (mm) Solution

-0.023 Replace or replate. -0.027 Replace or replate.

Nominal diameter (mm) Standard interior diameter (mm) Maximum inner diameter (mm) Solution

55 ～ 75 +0.060 ～ +0.190 +0.30 Replace the bushing. 80 ～ 120 +0.060 ～ +0.195 +0.30 Replace the bushing.

Nominal diameter (mm)

Standard thickness (mm) 95 ～ 160 t2.42 - 2.48

165 ～ 250 t2.92 - 2.98 Minimum thickness (mm) Solution

t2.37 Replace the slide ring. t2.87 Replace the slide ring.