Procedures for Assembly and Disassembly of Operation Remote Control Valve

1.Maintenance Procedures (1) Required tools and tightening torque

Tool Dimensions (mm) Part number Part name Screw size Tightening torque (N•m)

Wrench 22 312 Adjusting nut M14 68.6 ± 4.9 32 302 Disk M14

Special jig (diagram in Attached diagram 2. Joint disassembly jig page278) 24 301 Joint M14 47.1 ± 2.9

Other

(2)Maintenance standards

Note: It is desirable for seal materials such as O-rings to be replaced with each disassembly, but it is acceptable to reuse these after it is confirmed that they are not damaged.

・ Vapor corrosion inhibitor ・Sandpaper (#1000, #2000) ・White kerosene ・Whetstone

・Heat-resistant grease ・Vice

Maintenance inspection item Standard

Leak amount When handle is in neutral 1000 cc/min or more During operation 2000 cc/min or more If either condition occurs, replace the remote control valve as one unit. Remarks

Conditions Primary pressure 2.94 MPa Oil viscosity 23 mm2/s

Spool When wear on the sliding sections exceeds wear on the non-sliding sections by 10 μm or more, replace the remote control valve as one unit. The same approximate conditions as those listed above for leak amount are expected when the condition on the left occurs.

If the end section is worn by 1 mm or more, perform replacement.

Push rod

Operation section backlash

Operation stability Replace the operation section disk (302) and joint section (301) if there is backlash of 2 mm or more due to wear.

If abnormal noise, hunting, or a drop in primary pressure occurs and the problem cannot be resolved with "4. Causes of Trouble and Countermeasures", replace the remote control valve as one unit. Make adjustments if the backlash is due to looseness in the tightening sections.

2.Disassembly Procedures [1] Preparations 1) Prepare a sufficiently spacious, solid and stable work platform so that parts will not fall or move during work. 2) Prepare the tools and materials indicated in "1. Maintenance Procedures (1) Required tools and tightening torque". 3) When disassembling the valve, read the disassembly procedures thoroughly before following the sequence below. The numbers in the parentheses after the part names indicate codes in "Attached diagram 1. Remote control valve assembly cross-section diagram Attached diagram 1. Remote control valve assembly cross-section diagram”.

[2] General work precautions 1) 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. 2) If parts are struck or pulled with excessive force during work because they are tight, this may cause burrs or damage which lead to faulty assembly causing reduction in performance or oil leaking. Perform work carefully and thoroughly. 3) Rust may form on parts due to moisture or debris if the valve is left disassembled or if work is abandoned in the middle of disassembly. If work must be halted, be careful about preventing rust from forming and dust settling on parts.

[3] Disassembly procedure 1) Clean the remote control valve with white kerosene. •Place plugs in each port. 2) Use copper plate (or lead plate) to secure the remote control valve in a vise. 3) Remove the bellows (501). •Be careful not to tear the bellows.

4) Use a wrench on the bolt width of the adjusting nut (312) and disk (302) to loosen them, and remove the adjusting nut and disk.

5) Use a jig to rotate the joint (301) to the left and loosen it. •The diagram shows the valve with the jig installed. •If the return springs (221) are strong, the plate (151), plugs (211), and push rods (212) will rise at the same time the joint is loosened, so be careful of parts flying off when removing the joint.

6) Remove the plate (151).

7) If the return springs (221) are weak, the plugs (211) will remain in the casing (101) due to the sliding resistance of the O-rings (214), so use a flathead screwdriver to remove them. •Use the groove in the outer circumference of the plugs and remove them while making sure they are not damaged by an unbalanced load. •Use caution as plugs may fly off when they are being removed due to the return springs.

8) Remove the push rods (212), plugs (211), pressure reducing valve assemblies and the return springs (221) from the casing (101). •Record the relation of parts to the casing hole positions through marking, etc.

9) For disassembly of pressure reducing valves, press in the spring seatings, move the spring seatings (216) to the side while bending the secondary pressure springs (241), and remove the springs from the spools (201) by passing the springs through the larger hole of the spring seatings.

Next, separate the spools, spring seatings, secondary pressure springs, and washers (217). •Be careful not to scratch the surface of the spools. •Do not lower the spring seatings by 6 mm or more. •Handle these parts as assemblies until assembly of the remote control valve.

10)Remove push rods (212) from the plugs (211).

11)Remove O-rings (214) and seals (213) from the plugs (211). Use a small flathead screwdriver, etc. to remove seals. •O-rings and seals cannot be reused.

Replace them with new parts.

12)Cleaning parts 1.Clean all parts by placing them in a rough cleaning container filled with white kerosene. (rough cleaning) 2.Clean all parts by placing them in a finish cleaning container filled with white kerosene, and thoroughly clean them up to the interior while slowly rotating them. (finish cleaning) Use a rag to thoroughly remove white kerosene adhered to parts. •Scratching can easily occur if cleaning of parts is begun just after parts are immersed in white kerosene, so let parts sit in white kerosene until debris and grease sufficiently loosen off from the surface of parts and float to the surface. •If the white kerosene is dirty, this will encourage damage to parts and result in reduced performance after reassembly. Thoroughly manage the level of cleanliness of the white kerosene. •Do not dry parts with compressed air, as this will damage parts and cause rust to form due to debris and moisture being dispersed into the atmosphere. 13)Preventing rust on parts

Apply an anti-rust agent to each part. •Rust will form on parts if they are left as is after cleaning, and this will cause reduced performance of functions after reassemly.

3.Assembly Procedures [1] Preparations 1) As with disassembly, prepare a work platform, tools and materials.

[2] General work precautions 1) Observe the same general work precautions as with disassembly. 2) When performing assembly, remove metal fragments and foreign matter from all parts, and check that there are no burrs or nicks on parts. If there are burrs or nicks, use a whetstone to remove them. 3) As a rule, replace all O-rings and backup rings with new parts. 4) When installing O-rings and backup rings, be careful not to damage them. (Apply a thin layer of grease to ensure smooth installation.) 5) When installing parts, using grease is good for preventing parts from falling. 6) Tighten bolts, etc. to the torque values indicated in page277 "Attached diagram 1. Remote control valve assembly cross-section diagram". Use the torque wrench to measure the tightening torque. 7) After assembly is complete, place plugs in all of the ports to prevent entry of debris.

[3] Assembly procedures 1) Insert washers (217), secondary pressure springs (241) and spring seatings (216) onto each of the spools (201) in that order.

Additionally, press in the spring seatings and move them to the side while bending the secondary pressure springs to pass the seatings over the larger holes and install them on each of the spools. •Do not lower the spring seatings by 6 mm or more.

2) Install the return springs (221) in the casing (101).

Install the pressure reducing valve assemblies in the casing. •Install them in the positions they were in before disassembly.

3) Install O-rings (214) on the plugs (211).

4) Install seals (213) on the plugs (211). •Install so that the seal lips are as shown in the diagram below.

*1 Seal *2 Plug *3 Push rod *4 Hydraulic oil application

5) Install push rods (212) into the plugs (211). •Apply hydraulic oil to surface of the push rods.

6) Install the plug assemblies into the casing (101).

If the return springs (221) are weak, they will be stopped by the sliding resistance of the Orings (214). •Be careful not to scratch the casing holes by forcing in the spools (201).

If the return springs are strong, use the plate (151) to install all 4 plug assemblies at the same time and temporarily tighten them with the joint (301). •Be careful of the plug assemblies and plate flying off.

7) Install the plate (151). 8) Use a jig, and tighten the joint (301) to the casing (101) to the specified torque.

Tightening torque: 47.1 ± 2.9 N・m

9) Install the disk (302) onto the joint (301). •Screw the disk in until it is equally touching each of the 4 push rods (212).

Secondary pressure will cause faulty operation of the machine if the disk is screwed in too much, so pay attention to adjustment of the tightening position.

10)Install the adjusting nut (312), use a wrench on the bolt width of the disk (302) to secure it, and tighten the adjusting nut to the specified torque.

Tightening torque: 68.6 ± 4.9 N・m •During tightening, do not move the disk position.

11)Apply grease to the rotating section of the joint (301) and to the top of the push rods (212).

12)Install the bellows (501). •Be careful not to tear the bellows.

13)Inject vapor corrosion inhibitor into each port and then place plugs in the ports.

4.Causes of Trouble and Countermeasures

It is not always easy to find where the source of trouble is located. A few problems that may sometimes occur are listed in the table below. Repair of these problems can be difficult, so see the suggested causes and solutions in the table for assistance.

The table below shows general symptoms, suggested causes and also solutions. However, 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. Also keep in mind that solutions other than those listed in the table may sometimes be necessary.

The table below does not include all possible causes and countermeasures. Accordingly, further investigation of problems and causes should be done by an experienced and qualified repair person, as necessary. Symptom Cause Solution

Secondary pressure is not rising. 1. Insufficient primary pressure 2. Secondary pressure spring(s) (241) is (are) broken or worn. 3. The gap between spool(s) (201) and the casing (101) is abnormally large. 4. There is backlash in the handle section.

Secondary pressure is unstable. 1. Sliding parts are sticking. 2. Tank line pressure is variable. 3. Air is getting into lines. 1. Maintain primary pressure. 2. Replace it (them) with new part(s). 3. Replace the remote control valve as one unit. 4. Disassemble and assemble or replace the handle section. 1. Repair the sticking sections. 2. Return directly to the oil tank. 3. Perform operation several times and let out air.

Secondary pressure is high. 1. Tank line pressure is high. 2. Sliding parts are sticking. 1. Return directly to the oil tank. 2. Repair the sticking sections.

Attached diagram 1. Remote control valve assembly cross-section diagram

Code Part name

101 Casing 151 Plate 201 Spool 211 Plug 212-1 Push rod (port 1, 3) 212-2 Push rod (port 2, 4) 213 Seal 214 O-ring 216-1 Spring seating (port 1, 3) 216-2 Spring seating (port 2, 4) Q'ty Code 1 217 Washer Part name Q'ty 4

1 221-1 Return spring (port 1) 4 221-2 Return spring (port 3) 1 1

4 221-3 Return spring (port 2, 4)

2 2 241-1 Secondary pressure spring (port 1, 3) 2 2 241-2 Secondary pressure spring (port 2, 4) 2 4 301 Joint 1

4 302 Disk 2 312 Adjusting nut 2 501 Bellows 1 1 1

Attached diagram 2. Joint disassembly jig