The K3V Axial Piston Pumps is developed by Kawasaki Heavy Industries Seiki Division. It has a swash plate design as well as an axial piston design and can be categorized in series pumps. They are connected in a way that one is regulated by the other and can achieve all types of variable control methods. This style, also used for pilot control, has high power density, it is self-priming and has significant advantages such as low noise and durable. These wonderful features are what draw manufacturers to this series of hydraulic pump.
kawasaki k3v pump structure and function
I am going to give you a description of the KAWASAKI K3V pump structure and function.
kawasaki k3v pump Construction
Swash Plate Group
This is composed of the swash plate (212), shoe plate (211), swash plate support(251), tilting bush (214), tilting pin (531) and the servo piston (532). The swash plate on the reverse side to the shoe location is of a cylindrical form which is “pillow” supported by the hydrostatic bearingprovided by the swash plate support.
The tilting bush is inserted into the swash plate and into this is installed the spherical portion of the tilting pin which in turn is coupled to the servo piston itself.
Any linear movement of the servo piston produced by regulator pressure applied to either of its ends is thereby translated through the tilting pin into an angular movement of the swash plate which thereby varies the tilting or swash angle of the pump. Screw adjusters and lock nuts are available to adjust the factory set maximum (954) and minimum (953) tilting angle conditions.
Valve Cover Group
This is composed of the valve cover (312), valve plate (313) and valve plate pin (885). The valve plate with its two “melon” shaped ports is installed onto the valve plate being located by the valve plate pin. These two ports serve to supply and exhaust oil to and from the cylinder block. The oil passage switched by the valve plate is connected to the externally piped suction and outlet pressure ports through the valve cover.
When the pump’s drive shaft is driven by a prime mover, the cylinder block being spline coupled to the shaft will also rotate. If the swash plate has been tilted, the pistons arranged in the cylinder block due to the shoe being retained on the swash plate surface will both rotate with the cylinder block and reciprocate once per revolution. Paying attention to one such piston then it will move away from the valve plate for half a rotation (suction stroke) and move towards the valve plate for the second half of rotation (oil delivery stroke). The larger the tilt angle is the longer the piston stroke and thereby the higher is the pump’s displacement. If the swash plate tilting angle however is zero then the piston makes no stroke and thereby delivers no oil.
In the case of the K3V63DT tandem pump this has the construction whereby two pumps complete with their individual regulators are connected together by a coupling (114) within the central valve block (312) and that the drive shaft on the front pump (111) is connected to the prime mover. The oil suction port is common to both the rear and front pumps. The two pumps however are each provided with independent delivery ports.
kawasaki k3v pump function
General Description
The KR3 series regulators have been designed to give varied controlled options for the K3V series of axial piston pumps ideally suited to their application to excavator type systems.
The control options covered are:
a) Total Power Control (Torque Summation)
b) Power Shift
c) Negative Displacement Control
d) Two Stage Maximum Flow Control
The operation of the regulator utilises a follower-type lever linkage system (611) connected between the pump’s servo piston (532), the main control spool (652) and the regulator body (613) itself. This lever arrangement is activated by a series of pilot pistons (621 & 643) together with their associated control springs (625, 626 & 646) from which the relevant regulator control characteristic is obtained. The use of such a feed back lever arrangement from the servo piston ensures a highly responsive and accurate control system.
The servo piston (532) is connected through the pivot point (531) to the swash plate of the pump. Movement of the servo piston (532) to the left increases pump displacement and to the right reduces it.
The servo piston (532) itself has an area ratio of 4:1 whereby the smaller piston area to the right is continuously connected to the pump’s outlet pressure. The larger diameter area of the servo piston to the left is fed from the main regulator spool (652), which as it pressurises this servo piston area progressively reduces the pump displacement.
The various lever and linkage arrangements within the regulator assembly are illustrated above. The main feedback lever is shown in the centre where the servo pivot (531) couples it to the servo piston. The spool pivot (874) couples the lever directly to the main control spool. Additionally the feedback pivot (897) couples this feedback lever to both the displacement lever (to the right) and to the power lever (to the left). The displacement lever is anchored to the regulator body by the fixed pivot pin (875) whereas the power lever is anchored in a similar manner by the fixed pivot (875A).
In order, to better understand the functioning of this assembly, the regulator itself will now be split into two separate halves. Firstly viewing the Power or Torque Summation Control (to the left) and then later that of the Negative Displacement control (to the right)
Torque Summation Control
The above sections specifically show the Torque Summation Control with their necessary feedback mechanisms. These figures should be studied such that a general familiarisation of the mechanism is built up. The following description will help in this understanding.
Pump outlet pressure is fed into the larger stepped diameter area of the Power control piston (621). Pressure feedback from the second pump unit is in addition fed into the smaller stepped diameter area. These two stepped areas are equal.
The consequence of which is that both pumps destroke together to the same displacement condition. The force so produced is balanced by the spring preload created by the inner (626) and outer (625) power springs. At low pump feedback pressures only the outer spring (625) is active and as combined pumps pressure force on the piston (621) increases then the inner spring (624) also becomes active. Consequently a change in spring rate changes at some point which provides the characteristic curve.
Movement of the piston (621) under the action of these pump(s) pressure forces is transmitted by the power push rod (623) against the springs (624 & 625). This movement shifts the power control lever (612) on its fixed pivot (875A) towards the right of the diagram. This movement is transmitted from the power control lever (612) via the feed back pivot (897) to the feedback lever (611), which rotates “clockwise” slightly around the servo pivot (531).
As the feed back lever (611) is also connected to the main spool (652) via (874) this causes the main spool to port pressurised oil to the larger diameter area of the pump’s servo piston, which in turn begins to destroke the pump. This action results in the main feedback lever (611) to shift in an anti-clockwise direction. A state of equilibrium will eventually exist whereby the servo piston position and thereby pump displacement is so maintained that the main control spool is back in a central metering condition. In this condition the pressure fed to the servo pistons larger diameter will maintain equilibrium.
This figure details a fall in delivery pressure, this time the Power Spring Pack releases and moves the Power Push Rod to the left of its previous position as the Power Piston force has now reduced due to the reduction in delivery pressure.
Again the movement of the Power Lever is transmitted via the Feed Back Pivot and the Main spool’s compression spring, eliminates backlash by pulling the Main Spool to the left which thereby meters the Large Servo Piston pressure to tank pressure. As the small side of the Servo Piston is connected to the pump delivery pressure the Servo Piston moves to the left such that the displacement of the pump increases towards maximum.
When the Servo Piston has reached its position the Feed Back Lever causes the Main Spool to control once more at the null position and steady state control is once again achieved.
Negative Displacement Control
The above sections specifically show the Negative Displacement Control with its necessary feedback mechanisms. These figures should be studied such that a general familiarisation of the mechanism is built up. The following description will help in this understanding.
The Negative control pressure signal acts onto the left end of the displacement piston and push rod (643). The force so produced is balanced by the spring preload created by the displacement pilot spring (646).
Any imbalance in this force creates a movement of the displacement control lever (613) on its fixed pivot (875). A movement of the piston to the right is transmitted from the displacement control lever (613) via the feed back pivot (897) to the feedback lever (611),
which rotates “clockwise” slightly around the servo pivot (531). As the feed back lever (611) is also connected to the main spool (652) via (874) this causes the main spool to meter pressurised fluid to the larger diameter area of the pump’s servo piston, which in turn begins to destroke the pump.
This action results in the main feedback lever (611) to shift in an anti-clockwise direction. A state of equilibrium will eventually exist whereby the servo piston position and thereby pump displacement is so maintained that the main control spool is back in a central metering condition. In this condition the pressure fed to the servo pistons larger diameter will maintain equilibrium.
This develops on the previous figure whereby this time the Servo Piston has now moved further to the right and closer towards minimum displacement. As can be seen the various lever angles have changed from the previous figure. As the Servo Piston has moved to the right the Feed Back Lever has now rotated about the Feed Back Pivot, causing the Main Spool to move back to the null position to the left of its previous position.Once again the Main Spool is porting enough fluid to maintain the pressure balance across the Servo Piston and hence the new Swash Plate position.
This develops on the previous figure whereby this time the Servo Piston has now moved further to the right and closer towards minimum displacement. As can be seen the various lever angles have changed from the previous figure.
As the Servo Piston has moved to the right the Feed Back Lever has now rotated about the Feed Back Pivot, causing the Main Spool to move back to the null position to the left of its previous position.Once again the Main Spool is porting enough fluid to maintain the pressure balance across the Servo Piston and hence the new Swash Plate position.
Kawasaki k3v pump disassembly and assembly
Kawasaki k3v pump disassembly – the first thing that you need to do is to remove the cover of the pump. If you follow the step-by-step instructions, you won’t have a problem doing that.
General Precautions
1. All hydraulic components are manufactured to a high precision. Consequently, before disassembling and assembling them, it is essential to select an especially clean place.
2. In handling a main pump, pay full attention to prevent dust, sand, etc. from entering into it.
3. When a pump is to be removed from the machine, apply caps and masking seals to all ports. Before disassembling the pump, re-check that these caps and masking seals are fitted completely, and then clean the outside of the assembly. Use a proper bench for working. Spread paper or a rubber mat on the bench, and disassemble the pump on it.
4. Support the body section of the casing carefully when carrying or transferring the pump. Do not lift by the exposed regulator, third pump etc.
5. This manual does not refer to the disassembly and reassembly of a regulator, a gear pump or any other accessory valving attached to the pump. These items being considered disposable items in their own right. Please therefore do not disassemble or reassemble them unless absolutely essential.
Tools
Before disassembling the pump, prepare the following tools beforehand.
| Name of tool | Quantity | Size (mm) |
| Vice mounted on bench(soft jaws) | 1 unit | |
| Hexagon wrench | Each 1 piece | 4, 5, 6, 8 and 14 |
| Socket wrench | Each 1 piece | 19 and 27 |
| Spanner | Each 1 piece | 19 and 27 |
| Screwdriver | 2 pieces | Medium Size |
| Plastic Headed Hammer | 1 piece | |
| Adjustable Angle Wrench | 1 piece | Medium Size |
| Pliers | 1 piece | Type TSR-160 |
| Steel Bar | 1 piece | Approx, size 10 x 8 x 200 |
| Torque Wrench | 1 piece | Capable of tightening |
| Loctite #262 | 1 piece | specified torques |
Kawasaki k3v pump disassembly
step1
Before disassembling, spread rubber sheet, cloth or similar material over the overhaul workbench top so as to prevent parts from being damaged.Remove dust, rust and other contaminants from surfaces of the pump with cleaning oil.
step2
Remove the drain port plug (468) and drain off the hydraulic oil from the pump casing.a. Remove all plugs from both the front and rear pumps.
step3
Remove the hexagon socket headed bolts and remove regulator from front pump.
a. Similarly, remove the regulator from rear pump.
step4
Loosen hexagon socket head bolts(401) which tighten the swash plate support (251), pump casing (271)
and valve block (312).
a. If a gear pump or is fitted to the rear surface of the pump, then remove it before working on the pump unit.
b. Repeat this sequence for both the front and rear pumps.
step5
Place pump horizontally on the workbench with its regulator mounting surface face down. Remove the hexagon socket head bolts (401) and separate the pump casing (271) from it’s valve block (312).
a Before lowering this surface onto the bench, spread the rubber sheet on to the work bench so as to prevent this surface from being damaged.
b. Repeat this sequence for both the rear and front pumps.
step6
Lift the cylinder (141) out of the pump casing (271) straight over the drive shaft (111). Additionally extract the pistons (151), set plate (153), spherical bush (156) and cylinder springs (157) simultaneously.
a. Take care not to damage any of the sliding surfaces of the cylinder spherical bush, shoes, swash plate, etc.
b. Repeat this sequence for both the rear and front pumps.
step7
Remove the hexagon socket head bolts (406) and remove the seal cover (Front) (261).
a. By fitting a bolt into the “pulling-out” tapped hole of the seal cover, will easily remove it.
b. Take care not to damage the oil shaft seal installed in the cover.
Similarly for the rear pump, remove the hexagon socket headed bolts on rear pump, and remove it’s seal cover (Rear) (261) and rear cover (262).
IF a gear pump is fitted, remove this first.
step8
By tapping lightly on the flange section of the swash plate support (251) where it interfaces with the
pump casing side, separate the swash plate support from it’s pump casing.
a. Remove the drive shaft simultaneously with it’s swash plate support.
b. Repeat this sequence for both the rear and front pumps.
step9
Tapping lightly on the external shaft end of drive shafts (111, 113) with plastic hammer, extract each drive
shaft from it’s swash plate support. If required, extract the rolling bearing (123), bearing spacer (127), and snap ring (824) from the drive shaft (111,113).
a. Repeat this sequence for both the rear and front pumps.
b. Don’t reuse the bearings that you have extracted.
step10
Remove the valve plates (313, 314) from the valve block (312). These may be removed during sequence 5.
If required, execute sequence 12 and 13.
step11
Remove the stopper (L)(534), stopper (S)(535), servo piston (532) and tilting pin (531) from pump casing (271).
a.In removing the tilting pin, use a protection shield to prevent the pin head from being damaged. 25 OF 39
b. Loctite has been applied in production to the fitting areas of the tilting pin and servo piston, so care must be taken to prevent servo piston damage.
step12
Remove the needle bearing (124) and spline coupling (114) from the valve block (312).
a. Don’t remove the needle bearing unless it definitely requires replacement.
b. Don’t loosen the hexagon stroke adjustment nuts of valve block or swash plate support. If loosened,
the flow setting will be changed. June 2004
This completes the disassembly procedure.
Kawasaki k3v pump assembly
1.Fit the servo piston (532), tilting pin (531), stopper (L)(534) and stopper (S)(535) to the pump casing (271).
a.In tightening the servo piston and tilting pin to the pump casing, use a protector to prevent the tilting pin head and feedback pin from being damaged.
b.Apply loctite (medium) to the threaded section of tilting pin and servo piston and allow to set.
2.Fit the swash plate support (251) to it’s pump casing (271), by tapping the former lightly with a hammer.
a.Repeat this sequence for both the rear and front pumps.
3.Place pump casing with its regulator-fitting surface down on the bench. Fit the tilting bush of the swash plate to it’s tilting pin (531) and then fit the swash plate (212) to it’s swash plate support (251) correctly. Simultaneously fit the O-ring.
a.Confirm with ones fingers that the swash plate is bedded down correctly by ensuring that it could be removed
smoothly.
b. Apply grease to the sliding sections of the swash plate and swash plate support, and then smoothly fit the
drive shaft through it.
c. Repeat this sequence for both the rear and front pumps. In the case that one has disassembled the roller bearings then sequence 4 and 5 should be followed.
4.Install the bearing spacer (127) on to the drive shaft (111,113), and then next install the roller bearing (123) to this drive shaft.
5.Install the snap ring (824) onto the drive shaft (111,113).
6.Fit the drive shaft assembly (complete with bearing (123), bearing spacer (127) and snap ring (824)) to it’s swash plate support (251).
a. Do not tap the drive shaft with a hammer as damage may occur.
b. Assemble the shaft assembly into
it’s support by tapping the outer
race of bearing lightly with plastic
hammer. Fit them fully, using steel bar or so on.
c. Repeat this sequence for both the rear and front pumps.
7.Install the new oil seal (774) into the seal cover (F)(261) and seal cover (R()(263).
8.Assemble the front seal cover(F)(261) into the pump casing (271) and fix it with the hexagon socket head bolts (406). Similarly, assemble the rear seal cover (R)(261) or rear cover (263) into pump casing (271) and fix it with
hexagon socket head bolts.
a. Apply grease lightly to the oil seal within the seal cover.
b. Assemble them carefully, taking full care not to damage the oil seal.
9. Install the cylinder springs (157), spacer (158) and spherical bush (156) onto the cylinder (141). Fit the pistons (151) and shoe (152) through the set plate (153).
a. Repeat this sequence for both the rear and front pumps.
10. Assemble the piston shoe (151,152) and set plate (153) group onto and into the cylinder bores of the cylinder (141), springs (157), spherical bush (156) and spacer (158) group.
a. Repeat this sequence for both the rear and front pumps.
11.Fit the splined phases of the retainer and cylinder sub-assembly into the pump casing.
a. Repeat this sequence for both the Rear and front pumps.
b. If the needle bearing has been replaced then follow sequence 12.
12.Install the needle bearing (124) and splined coupling (114) into the valve block (312).
13.Fit the valve plate (313) on to the valve block (312), utilising the location pin.
a.Take care not to the mistake thesuction and delivery directions ofthe valve plate.
14.Fit the valve block (312) to it’s p casing (271), and tighten the hexagon socket headed bolts (401). Simultaneously install the O-Ring.
a. Repeat this sequence for both the rear and front pumps.
b. It is easiest to assemble the rear pump first.
c. Take care not to mistake the Valve plate / Valve Block direction of rotation.
15.Fit the drain port plug (468).
a. Repeat this sequence for both the rear and front pumps. This concludes the reassembly procedure.
Kawasaki k3v Pump Parts List
| No. | Part Name | Part Number | Q’ty | Class |
| Ill | Shaft(F) | P- 2933800982 | 1 | C |
| 113 | Shaft(R) | P- 2933800884 | 1 | C |
| 114 | Coupling | P- 2953801763 | 1 | C |
| 123 | Bearing; roller | P- PNUP308R1CS50 | 2 | C |
| 124 | Bearing; needle | P- PAJ 503518 | 2 | C |
| 127 | Spacer; bearing | P- 38800127 | 4 | C |
| 141 | Cylinder | P- 2933800787 | 2 | / |
| 151 | Piston | P- 38901151 | 18 | / |
| 152 | Shoe | P- 38900152 | 18 | / |
| 153 | Set plate | P- 2943800463 | 2 | C |
| 156 | Spherical bush | P- 29246100030 | 2 | C |
| 157 | Spring; cylinder | P- 2953801769 | 18 | C |
| 211 | Shoe plate | P- 6871000211 | 2 | |
| 212 | Swash plate | P- 2933800813 | 2 | / |
| 214 | Tilting bush | P- P1R2025125 | 2 | / |
| 251 | S.P. support | P- 2923800809 | 2 | c |
| 261 | Seal cover(F) | P- 2943800572 | 1 | c |
| 263 | Seal cover(R) | P- 2943800465 | 1 | c |
| 271 | Casing | P- 2923800807 | 2 | c |
| 312 | Valve block | P- 2923801021 | 1 | |
| 313 | Valve plate(R) | P- 3890R313N | 1 | / |
| 314 | Valve plate(L) | P- 3890L314N | 1 | / |
| 325 | Assist casing | P- 2933800944 | 1 | c |
| 401 | Screw | P- 2953801767 | 8 | |
| 406 | Socket screw | P- 0SBM820 | 8 | D |
| 407 | Socket screw | P- 0SBM655 | 3 | D |
| 466 | Plug | P- 0VP14 | 3 | D |
| 468 | Plug | P- 0VP34 | 4 | C |
| 490 | Plug | P- PBP1162403 | 21 | C |
| 531 | Pin; tilting | P- 2943800517 | 2 | / |
| 532 | Servo piston | P- 2943800462 | 2 | C |
| 534 | Stopper(L) | P- 2953801761 | 2 | C |
| 535 | Stopper(S) | P- 2953801762 | 2 | C |
| 541 | Seat | P- 29331800414 | 4 | / |
| 543 | Stopper 1 | P- 29332600311 | 2 | / |
| 544 | Stopper 2 | P- 29332600312 | 2 | / |
| 545 | Ball; steel | P- 0DW732 | 4 | / |
| 548 | Pin; feed back | P- 2953802202 | 2 | / |
| 702 | O-ring | P- 00RBG35W | 2 | D |
| 710 | O-ring | P- 00RBG95 | 2 | D |
| 717 | O-ring | P- 00RBG145 | 4 | D |
| 724 | O-ring | P- 00RBP8 | 16 | D |
| 725 | O-ring | P- 00RBP11 | 8 | D |
| 727 | O-ring | P- 00RBP14 | 1 | D |
| 728 | O-ring | P- 00RBP24 | 4 | D |
| 732 | O-ring | P- 00RBP18W | 2 | D |
| 774 | Oil seal | P- P15Z456812F | 1 | C |
| 789 | Back up ring | P- 0T2BP18 | 2 | D |
| 792 | Back up ring | P- 0T2BG35 | 2 | D |
| 806 | Nut | P- 0RNM16 | 2 | D |
| 808 | Nut | P- 0RNM20 | 2 | D |
| 824 | Snap ring | P- 0SR40 | 2 | D |
| 885 | Pin | P- PJR812 | 2 | C |
| 886 | Pin; spring | P- 0SPV614 | 4 | D |
| 901 | Bolt; eye | P- 0EBM10 | 2 | C |
| 953 | Set screw | P- PSSSM1630 | 2 | C |
| 954 | Screw | P- 2953801768 | 1 | C |
| 955 | Screw | P- 2953801866 | 1 | C |
| 981 | Name plate | P- PNPA2550B | 1 | / |
| 983 | Pin | P- 0SK2548 | 1 | / |
kawasaki k3v pump repair videos
kawasaki k3v pump repair PDF
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With our repair manual you save on expensive workshop labour costs. You will also learn how to operate safely, extend the life of your kawasaki k3v pump, and save money in maintenance and repair costs.
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