2-47
1. STRUCTURE1. STRUCTURE
Swing device consists swing motor, swing reduction gear.
Swing motor include mechanical parking valve, relief valve, make up valve and time delay valve.
Reduction gear
Relief valve
Time delay valve
Au
GB
SH
PG
Dr
GA
B(cw)
Mu
A(ccw)
PG
SH
B
A
GA
Oil level gauge
& oil supply port
Au
GB
SH
PG
Dr
Swing motor
Reduction gear oil
drain port
(PT 1/2)
Reduction gear grease
supply port
(PT 1/4)
Reduction gear
air bleed port
(PT 1/4)
Hydraulic circuit
Mu
16092SM01
GROUP 3 SWING DEVICEGROUP 3 SWING DEVICE
Port Port name Port size
A Main port
Ø
20
B Main port
Ø
20
Dr Drain port PF 1/2
Mu Make up port PF 1
PG
Brake release port PF 1/4
SH
Stand by port PF 1/4
GA, GB
Gauge port PF 1/4
Au
Air vent port PF 1/4
2-48
SWING MOTORSWING MOTOR
1 Body
2 Oil seal
3 Roller bearing
4 Snap ring
5 Shaft
6 Bushing
7 Stop ring
8 Pin
9 Shoe plate
10 Cylinder block
11 Spring
12 Ball guide
13 Set plate
14 Piston assy
15 Friction plate
16 Separate plate
17 Brake piston
18 O-ring
19 O-ring
20 Brake spring
21 Rear cover
22 Needle bearing
23 Pin
24 Valve plate
25 Wrench bolt
26 Plug
27 Back up ring
28 O-ring
29 Spring
30 Check
31 Relief valve
32 Anti-inversion valve
33 Time delay valve
34 Wrench bolt
35 Plug
36 O-ring
37 Plug
38 Plug
39 Plug
40 Name plate
41 Rivet
42 Level gauge
43 Plug
44 O-ring
45 O-ring
46 Back up ring
37
31
39
33,34 38
2532
35,36
45
44
46
43
26
30
29
28
27
2 3 4
765
1
9
16
14
13
15 18
19
24
21 22 40,41
11
12
10
17 20
DETAIL K
823
K
42
1)1)
16092SM02
2-49
REDUCTION GEARREDUCTION GEAR
1 Casing
2 Drive shaft
3 Spacer
4 Roller bearing
5 Oil seal
6 Roller bearing
7 Thrust plate
8 Carrier 2
9 Stop ring
10 Ring gear
11 Knock pin
12 Pinion gear
13 Thrust washer
14 Planet gear 2
15 Pin & bushing
16 Spring pin
17 Sun gear 2
18 Carrier 1
19 Side plate 1
20 Pin 1
21 Needle cage
22 Bushing 2
23 Planet gear 1
24 Lock washer
25 Side plate 3
26 Sun gear 1
28 Plug
29 Plug
30 Socket bolt
33 Cover plate
34 Hexagon bolt
35 Lock plate
36 Hexagon bolt
37 Stop ring
38 Side plate 2
24
36
35
12
3
34
33
4
2
29
28
5
9
8
10
17
18
25
30
6
1
38
21
23
19
16
20
15
14
22
11
13
7
37
26
2)2)
16092SM03
2-50
2. PRINCIPLE OF DRIVING2. PRINCIPLE OF DRIVING
2.1 Generating the turning force
The high hydraulic supplied from a hydraulic pump flows into a cylinder (10) through valve casing of
motor (21), and valve plate (24).
The high hydraulic is built as flowing on one side of Y-Y line connected by the upper and lower sides of
piston (14).
The high hydraulic can generate the force, F1=P
×
A (P : supplied pressure, A : water pressure area),
like following pictures, working on a piston.
This force, F1, is divided as N1 thrust partial pressure and W1 radial partial pressure, in case of the
plate of a tilt angle,
α
.
W1 generates torque, T=W1+R1, for Y-Y line connected by the upper and lower sides of the piston as
following pictures.
The sum of torque (
Σ
W1
×
R1), generated from each piston (4~5 pieces) on the side of a high
hydraulic, generates the turning force.
This torque transfers the turning force to a cylinder (10) through a piston; because a cylinder is
combined with a turning axis and spline, a turning axis rotates and a turning force is sent.
F1
f1
N1
W1
Y
Y
R1
P
A
O
W1
Cylinder
Low
pressure
High
pressure
Pistion
21078TM05
2-51
MAKE UP VALVEMAKE UP VALVE
In the system using this type of motor, there is no counter balance functioning valve and there
happens the case of revolution exceeding hydraulic supply of motor. To prevent the cavitation
caused by insufficient oil flow there is a make up valve to fill up the oil insufficiency.
A make up valve is provided immediately before the port leading to the hydraulic oil tank to secure
feed pressure required when the hydraulic motor makes a pumping action. The boost pressure
acts on the hydraulic motor's feed port via the make up valve.
Pressurized oil into the port B, the motor rotate counterclockwise.
If the plunger of MCV moves neutral position, the oil in the motor is drain via left relief valve, the
drain oil run into motor via right make up valve, which prevent the cavitation of motor.
Make up check valveMake up check valve
Relief valve
A B
2)2)
21092SM04
2-52
1 Body
2 Seat
3 Plunger
4 Spring
5 Adjusting screw
6 Piston
7 Bushing
8 Spring seat
9 Shim
10 O-ring
11 Back up ring
12 O-ring
Construction of relief valveConstruction of relief valve
The valve casing contains two cartridge type relief valves that stop the regular and reverse
rotations of the hydraulic motor. The relief valves relieve high pressure at start or at stop of swing
motion and can control the relief pressure in two steps, high and low, in order to insure smooth
operation.
Function of relief valve Function of relief valve
Figure illustrates how the pressure acting
on the relief valve is related to its rising
process. Here is given the function,
referring to the figure following page.
11
10
7
8
12
1
4
2
5
6
9
3
P=pressure, T=time
P
Ps
P
2
P
1
1
2
3
4
T
RELIEF VALVERELIEF VALVE3)3)
(1)(1)
(2)(2)
14007A2SM05
2-48(2)
2-53
Ports (P,R) at tank pressure.
When hydraulic oil pressure (P×A
1
) reaches the preset force (F
SP
) of spring (4), the plunger (3)
moves to the right as shown.
P
1
×A
1=
Fsp+Pg×A
2
A2 m h n
g
A1
P
R
P=P
1
g
4
3
P
1
=
Fsp+Pg×A
2
A
1
①
②
14007A2SM06
14007A2SM07
2-54
The oil flow chamber g via orifice m and n. When the pressure of chamber g reaches the preset
force (F
SP
) of spring (4), the piston (6) moves left and stop the piston (6) hits the bottom of bushing
(7).
When piston (6) hits the bottom of bushing (7), it stops moving to the left any further. As the
result, the pressure in chamber (g) equals (Ps).
Ps×A
1
=Fsp+Ps×A
2
Ps=
Fsp
A
1
-
A
2
P=P
2
4 m n
g
67
P=Ps
67
g
③
④
14007A2SM08
14007A2SM09
2-55
BRAKE SYSTEMBRAKE SYSTEM
Control valve swing brake system Control valve swing brake system
This is the brake system to stop the swing motion of the excavator during operation.
In this system, the hydraulic circuit is throttled by the swing control valve, and the resistance
created by this throttling works as a brake force to slow down the swing motion.
Mechanical swing parking brake systemMechanical swing parking brake system
This is function as a parking brake only when all of the RCV lever (except travel pedal) are not
operated.
Brake assemblyBrake assembly
Circumferential rotation of separate plate
(16) is constrained by the groove located
at housing (1). When housing is
pressed down by brake spring (20)
through friction plate (15), separate plate
(16) and brake piston (17), friction force
occurs there.
Cylinder block (10) is constrained by this
friction force and brake acts, while brake
releases when hydraulic force exceeds
spring force.
Work
Deceleration Stop
MCV A, B opened MCV A, B throttled MCV A, B closed
MCV
MCV
MCV
AB
AB
AB
10
15
1
16
17
20
Groove
1 Housing
10 Cylinder block
15 Friction plate
16 Separate plate
17 Brake piston
20 Spring
4)4)
(1)(1)
(2)(2)
①
2-48(1)
21092SM15
2-56
Operating principleOperating principle
When one of the RCV lever (1) is set to the operation position, the each spool is shifted to left
or right and the pilot oil flow is blocked. Then the pilot oil go to SH of the time delay valve (33).
This pressure moves spool (5) to the leftward against the force of the spring(8), so pilot pump
charged oil (P3) goes to the chamber G through port PG.
This pressure is applied to move the piston (17) to the upward against the force of the spring
(20). Thus, it releases the brake force.
20
17
G
1
2
P3
5
8
SH
PG
33
1 RCV lever
2 Main control valve
5 Spool
8 Spring
17 Brake piston
20 Brake spring
33 Time delay valve
②
a.
16092SM16
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