V-10
qHigh efficiency, high pres-
sure operation
Th e uniqu e pr essure regu lator and
pressure balance mechanism, plus the
exclusive three-point ring support sys-
tem has improved performance during
high pressure operation. The pump
operates with high efficiency and sta-
ble performance up to a maximum of
140kgf/cm
2
(2000 psi).
wLow vibration and noise
levels
The new mechanisms reduces vibra-
tion a nd noise levels. Of pa rticular
note is the unique and exclusive three-
point support system which uses, a
regulating piston and a bias piston to
eliminate vibration. The mechanism,
tog ethe r w i th imp rove ment s t o t h e
shape of the inlet and outlet ports and
high performance journal bearings ,
ha s re duced t he nois e le ve l du ring
operation.
eFast response
The ring stopper mechanism serves to
allow swift response whether in start-
ing, stopping, or with load fluctuations,
for high precision operation.
r
Stable discharge with sharp
cut-off characteristics
A revolutionary pressure compen-
s ator t y p e p r e s s u r e r e g u l a tion
mechanism provides, stable sharp
cut-off characteristics. The com-
pensator serves to provide stable
and constant volume through our
the pressure ranges.
tHigh efficiency operation
with reduced power loss
Efficiency has been improved with
the new mechanisms and Nachi's
high precision machining technolo-
gy. Power loss has been reduced,
expecially during dead-heading.
yEasy adjusting in mainte-
nance and handling
Maintenance is easier due to the
positioning of the pressure adjust-
ing m ech anism and the vol ume
adjusting mechanism on the same
side of the pump.
Features
Overview
The VDC series high pressure vari-
able volume vane pumps are a new
series of pumps. In addition to Nachi's
three exclu sive mechani sms (pres-
sure control; pressure balance; ring
stopper mechani sm), a uniqu e and
exclusive three-point ring support sys-
tem which makes maximum utilization
of high pressure oil has been adopted
to provide stable high pressure and
quiet operation.
The new series of hydraulic pumps
are ideal for applica tions, such as:
machine tools, industrial machinery
and vehicles.
VDC SERIES HIGH PRESSURE TYPE
VARIABLE VOLUME VANE PUMP
VDC Series
High-Pressure Type Variable Volume Vane Pump
7.9 to 31.7gpm
2000psi
V-11
Specifications
Single Pump
Double Pump
V-12
¡Handling
zThe r o t ation i s c l o c k w ise a s
viewed from the shaft side.
xDrain Drain piping must be direct
piping up to a point that is below
the tank fluid level, and piping
should comply with the conditions
sho wn in the ta ble be low to
ensure that back pressure due to
pipe resistance does not exceed
0.1MPa. When using a pump that
has drain ports at two locations,
use the drain port that is higher
after the pump is installed.
In the case of a double pump,
ru n separ at e pipes from b ot h
the shaft side and the head side
drains dir ectly connect to the
tank, so the drain pipe is below
the surface of the oil.
cDischarge Volume Adjustment
T h e d i s c h a r g e f l o w r a t e i s
decreased by clockwise (right-
ward) rotation of the discharge
r a t e a d j u s t i n g s c r e w , a n d
increased by counterclockwise
(leftward) rotation.
Loosen the lock nut before making
adjustments. After adjustment is
complete, re-tighten the lock nut.
The graph below provides general
guidelines for the relationship
between the rotation angle of the
flow rate adjusting screw and the
no-load discharge rate.
However: Q=q
×
N
×
10
−3
Q :
No-load Discharge RateQr/min
q : Volume c m
3
/rev
N : Revolution Speed min
−1
vPressure Adjustment Pressure is
increased by clockwise (right-
ward) rotation of the discharge
rate adju stin g scr e w, an d
decreased by counterclockwise
(leftward) rotation.
Loosen the lock nut before making
adjustments. After adjustment is
complete, re-tighten the lock nut.
bP-Q adjustment at time of ship-
ment from plant
°
Flow adjustment: Has already
b e e n a d j u s t e d t o m a x i m u m
flow i ndica ted f or t he m odel
type in the catalog.
°
P r e s s u r e a d j u s t m e n t : H a s
already been adjusted to pre-
set pressures given in Table
below:
nThrust Screw and Stopper
The thrust sc rew and stopper
are pre cisio n a dju sted at the
factory during assembly. Never
touch them.
See callouts 15/43 and 15/38 in
the VDC-1A and 2A/3A cross-
section diagrams on pages V-19
and V-20.
mAn unlo a d c i rcuit i s r e q uired
when the motor is started under
conditi on λ
−
∆ . Contact your
agent about the unload circuit.
,Initial Operation Before operating
the pump for the first time, put
the pump discharge side into the
no-load state and then repeatedly
start and stop the motor to bleed
all air from inside the pump and
the suction piping. After confirm-
ing that the pump is discharging
oil, continue the no-load opera-
tion for at least 10 minutes to dis-
charge all the air from the circuit.
Provide an air bleed valve in cir-
cuits where it is difficult to bleed
air before startup.
.Sub Plate
Use the table below for to speci-
fy a sub plate type when one is
required.
(Continued on following page)
0
0.7
1.2
0.5
0.4
0.6
2.4
1.8
3.0
4.2
3.6
90 180 270 360 450
VDC-3
3
Pump capacity q in /rev
Note)
The values indicated above are at
maximum pump discharge volume
with the flow volume adjusting screw
at the 0°position.
The broken line shows the flow volume
adjustment range lower limit value.
Model No.
Item
VDC-1 VDC-2 VDC-3
Pipe Joint
Size
At least
1/4"
At least
1/4"
At least
3/8"
Pipe I.D.
At least
φ
7.6
At least
φ
7.6
At least
φ
9.6
Pipe
Length
1m or
le s s
1m or
le s s
1m or less
CW: Pressure increases
CCW: Pressure decreases
CCW: Flow increases
CW: Flow decreases
Pump pressure
adjusting range
Preset pressure
when shipped
from plant
2: 15
~
35 kgf/cm
2
(214
~
500 psi)
3: 20
~
70 kgf/cm
2
(286
~
1000 psi)
4: 50
~
105 kgf/cm
2
(714
~
1500 psi)
5: 70
~
140 kgf/cm
2
(1000
~
2000 psi)
35 kgf/cm
2
(500 psi)
35 kgf/cm
2
(500 psi)
50 kgf/cm
2
(714 psi)
70 kgf/cm
2
(1000 psi)
V-13
⁄0Foot Mounting
For a double pump with VDC-3 foot
mounting, the foot mounting kit
and pump are sold as a set. When
only t he mounting feet are
required, pump mounting bolts,
washers and other parts are sold
together as the Foot Mounting Kit.
⁄1Hydraulic oil: When the pump is
to be used at pressures of less
than 70kgf/cm
2
(1000 psi), use
good q u a l i t y p e troleum b a se
hydrau l i c o i l w i th a r a ting o f
30
~
50cSt (141
~
232 SUS) (equiv-
alent to I S O VG32 ) at 4 0 ˚C
(104˚F). Operation at pressure
exceeding 70kgf/cm2 (1000 psi),
use oil with a rating of 50
~
70cSt
(232
~
324 SUS) (equivalent to
ISO VG68) at 40˚C (104˚F).
⁄2The operating temperature range
is 15 to 60°C. When the oil temper-
ature at startup is 15°C or less,
perform a warm-up operation at
low pressure until the oil tempera-
ture reaches 15°C. Use the pump
in an area where the temperature
is within the range of 0 to 60°C.
⁄3Suc tio n pr ess ure is -0.0 3 t o
+0.03MPa (-4.3 to +4.3psi), and the
suction port flow rate should be no
greater than 2m/sec.
⁄4Avoid p ulley, gear, and o ther
drive systems that impart a radi-
al or thrust load on the end of
the pump shaft.
Moun t the pump s o its p u mp
shaft is oriented horizontally.
⁄5Provide a suction strainer with a
filtering grade of about 100
µ
m
(150 mesh). For the return line to
the tank, use a 25
µ
m line filter.
⁄6Manage hydraulic operating fluid
so contamination is maintained at
class NAS10 or lower. Take care
to avoid contamination with water
and oth er foreign matter, and
wat c h o ut for dis c olo r ati o n.
Whitish fluid indicates that air has
contaminated the fluid, and brown-
ish fluid indicates the fluid is dirty.
⁄7Contact your agent about using
water- and glycol-based hydraulic
operating fluids.
⁄8At startup, repeat the inching
operation (start-stop) to bleed air
from the pump and pipes.
⁄9Equip an air bleed valve in cir-
cuits where it is difficult to bleed
air before startup.
¤0To ensure proper lubrication of the
pump's rubbing surfaces, supply
oil to the i nterior of the pump
before starting operation.
¤1Alignment: Alignment between
the pump shaft and the motor
shaft should be parallel within
0.05mm (0.002 inch), and within
1˚ for the angle between the two
s h a f t s. Use a pump mounting
base of sufficient rigidity.
Pump Model No. Sub Plate Number Motor (kW)
VDC-1A-1A*-20
MVD-1-115-10 0.75 to 1.5
MVD-1-135-10 2.2 to 3.7
VDC-1A-2A*-20
MVD-1-115Y-10 0.75 to 1.5
MVD-1-135Y-10 2.2 to 3.7
VDC-2A-*A*-20
MVD-2-135-10 2.2 to 3.7
MVD-2-160-10 5.5
VDC-2A-2A*-20 MVD-2-160Z-10 5.5
Sub Plate Number
Understanding Model Numbers
Single Pump
– – ––
Design code
E20 = VDC-1A, VDC-2A, VDC-3A/B
E35 = VDC-1B, VDC-2B
20 = All metric version
Pressure adjusting range
2: 15
~
35 kgf/cm
2
214
~
500 psi
3: 20
~
70 kgf/cm
2
286
~
1000 psi
4: 50
~
105 kgf/cm
2
714
~
1500 psi
5: 70
~
140 kgf/cm
2
1000
~
2000 psi
VDC series variable volume vane pump
Pump size: 1, 2, 3
Mounting
A: Foot mounting
B: Flange mounting
Pressure volume characteristics
A: Constant volume type
Ring size: 1, 2
VDC 2 A 1 A 4 20/35
Note: Remote control pressure compensating type is available. Please check with factory.
V-14
Double Pump
Installation Dimension Drawings
VDC-1A-*A*-*20 mm(inch)
V-15
VDC-2A-*A*-*20 mm(inch)
VDC-1B-*A*-E35
(SAE-A MOUNT)
VDC-3A-1A*-*20 mm(inch)
V-16
VDC-2B-*A*-E35
(SAE-B MOUNT)
VDC-3B-A*-20 mm(inch)
(SAE-C MOUNT)
VDC-11B-*A*-*A*-E35 mm(inch)
V-17
VDC-12B-*A*-*A*-E35 mm(inch)
VDC-22B-*A*-*A*-E35 mm(inch)
VDC-13B-*A*-*A*-*20 mm(inch)
V-18
Performance Curves
Power loss
Typical characteristics at hydraulic operating fluid kinematic viscosity of 32 mm
2
/s
pressure
0 3.5 10.5 14.0
500 1500 2000
(mpa)
(psi)
7.0
1000
1800min
–1
1500min
–1
0
0.5
1.5
2.0
1.0
VDC-1
Power loss at full cutoff kW
(mpa)
(psi)
Pressure
0 3.5 10.5 14.0
500 1500 2000
7.0
1000
1800min
–1
1500min
–1
1
3
4
2
VDC-2
Power loss at full cutoff kW
(mpa)
(psi)
Pressure
0 3.5 10.5 14.0
500 1500 2000
7.0
1000
1800min
–1
1500min
–1
1
3
5
4
2
VDC-3
Power loss at full cutoff kW
VDC-1A(B)-1A3-20/35 VDC-2A(B)-1A3-20/35 VDC-3A(B)-1A3-20
VDC-1A(B)-1A5-20/35 VDC-2A(B)-1A5-20/35 VDC-3A(B)-1A5-20
VDC-1 VDC-2 VDC-3
Noise Characteristics
VDC-1*-1A*-20/35 VDC-2*-1A*-20/35 VDC-3*-1A*-20/35
V-19
VDC-1A-*A*-E20/35
VDC-2A-*A*-E20/35
Cross-sectional Drawing
Part No.
Part Name
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Ke y
Pin
Holder
Holder
Orifice
Oil seal
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
Backup ring
Part No.
Part Name
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
Backup ring
Cap
Snap ring
Screw
Screw
Screw
Screw (stopper)
Screw
Plug
Plug
Pole
Nameplate
Valve body
Spool
Holder
Plunger
Spring
Retainer
Screw
Nut
O-ring
O-ring
Plug
Plug
Screw
Note) Seal kit = VCBS-101A00 (VDC-1A)
Seal kit = VCBS-101B00 (VDC-1B)
Seal kit = VCBS-102A00 (VDC-2A)
Seal kit = VCBS-102B00 (VDC-2B)
Part
No.
Applicable Pump Model No.
VDC-1A-*-20 VDC-2A-*-20
Seal Kit Number
VCBS-101A00 VCBS-102A00
Part Name Part Number Q'ty Part Number Q'ty
24 Oil seal TCV-224211 1 TCN-325211 1
25 O-ring S85(NOK) 1 1A-G115 1
26 O-ring AS568-034 1 AS568-150 1
27 O-ring AS568-026 1 AS568-134 1
28 O-ring 1A-P14 1 1A-P18 1
29 O-ring 1A-P22 1 1A-G35 1
30 O-ring 1A-P20 1 1A-G35 1
31 O-ring 1A-P5 2 1A-P9 2
32 O-ring 1A-P6 4 1A-P7 4
33 O-ring 1A-P25 1 1A-G35 1
34 O-ring 1A-P22 1 1A-G35 1
35 O-ring 1A-P10A 1 1A-P15 1
36 Backup ring
VCB34-101000
1
VCB34-102000
1
37 Backup ring
VCB34-201000
1
VCB34-202000
1
57 O-ring 1A-P14 1 1A-P14 1
58 O-ring
1B-P6(Hs90)
3
1B-P6(Hs90)
3
Part No.
Part Name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Body (1)
Body (2)
Cover (1)
Cover (2)
Shaft
Ring
Vane
Plate (S)
Plate (H)
Piston (1)
Piston (2)
Bearing
Bearing
Spring
Thrust screw
Screw
Nut
Nut
Seal Component Table (VDC-1*, VDC-2*)
V-20
VDC-3A-1A*-E20
39
38
29
5
27
14
12
8
28
17
32 7
11
22
27
21
29
16
18
21
40
30
2
13
42
24
25
10
15
1
34
9
13
23
33
3
35
41
19
6
54
53
45
46
44
56
48 52
47
49
51
50
4
37
31
43
26
20
36
Part No.
Part Name
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Nut
Nut
Ke y
Pin
Holder
Orifice
Oil seal
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
O-ring
Cap
Part No.
Part Name
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Body (1)
Body (2)
Mounting
Cover (1)
Cover (2)
Shaft
Ring
Vane
Plate (S)
Plate (H)
Piston (1)
Piston (2)
Bearing
Spring
Thrust screw
Screw
Part No.
Part Name
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
Snap ring
Screw
Screw
Screw
Screw
Screw (stopper)
Screw
Plug
Washer
Nameplate
Pole
Valve body
Spool
Holder
Plunger
Spring
Retainer
Screw
Nut
O-ring
O-ring
Plug
Plug
Screw
Seal Component Table (VDC-3*)
Note) Seal kit = VCBS-103B00
Part
No.
Applicable Pump Model No.
VDC-3A(B)-*-20
Seal Kit Number
VCBS-103B00
Part Name Part Number Q'ty
23 Oil seal TCN-385811 1
24 O-ring 1A-G130 1
25 O-ring
AS568-154(Hs90)
1
26 O-ring
AS568-151(Hs90)
1
27 O-ring 1A-G40 2
28 O-ring 1A-P22 1
29 O-ring 1A-P9 2
30 O-ring 1A-P7 2
31 O-ring 1A-P7 2
52 O-ring 1A-P14 1
53 O-ring 1B-P6(Hs90) 3
V-21
Part
No.
Part Name
VDC-11A-*-*-20 VDC-12A-*-*-20 VDC-22A-*-*-20 VDC-13A-*-*-20
Part Number
Q'ty
Part Number
Q'ty
Part Number
Q'ty
Part Number
Q'ty
6 O-ring
1A-G60 1 1A-G60 1
7 O-ring 1A-G85 1 1A-G45 1 1A-G60 1 1A-G85 1
VDC Series
Double Pump
Note)
• See the description of the single pump for seal parts that are not included in the list.
List of Sealing Parts
4
7
9
10
2
5
6
8
1
3
Part No.
Part Name
1
2
3
4
5
6
7
8
9
10
Body (2)
Body (3)
Shaft (S)
Shaft (H)
Joint
O-ring
O-ring
Screw
Screw
Screw
Note: Other parts are same as single pump.